BACKGROUND

We have previously shown promising activity of hepatic arterial infusion (HAI) oxaliplatin combined with intravenous (IV) 5-fluorouracil (5-FU) and leucovorin (LV) as first-line chemotherapy in patients with colorectal liver metastases (CRLM) (intent-to-treat [ITT] objective response rate [ORR], 64%; secondary resection rate, 18%; overall survival [OS], 27 months). Whether this regimen could be beneficial after systemic chemotherapy failure is unknown.

METHODS

Patients with unresectable CRLM and history of systemic chemotherapy failure were treated bimonthly with HAI oxaliplatin (100 mg/m(2) 2 hours) combined with IV LV and IV bolus and infusional 5FU (modified LV5FU2 regimen).

RESULTS

Forty-four consecutive patients (median age 56 years; median number of prior systemic chemotherapy regimens, 2 range 1-5) were included, of whom 43 (98%) had previously received oxaliplatin (n = 34), irinotecan (n = 37), or both (n = 28). Patients received a median of nine cycles of HAI oxaliplatin and IV modified LV5FU2 (range 0-25). Toxicity included grade 3-4 neutropenia (43%), grade 2-3 neuropathy (43%), and grade 3-4 abdominal pain (14%). We observed 24 partial ORs (62%) among the 39 assessable patients (ITT ORR, 55%; 95% CI, 40-69%), including 17, 12, and 12 patients who had failed to respond to prior systemic chemotherapy with FOLFIRI, FOLFOX, or both, respectively. Tumor response allowed further R0 surgical resection (n = 7) or radiofrequency ablation (n = 1) of initially unresectable CRLM in eight patients (18%). Median progression-free survival and OS were 7 and 16 months, respectively.

CONCLUSIONS

HAI oxaliplatin and IV LV5FU2 is feasible, safe, and shows promising activity after systemic chemotherapy failure, allowing surgical resection of initially unresectable CRLM in 18% of patients.

OBJECTIVE

Mutations in the DNA mismatch repair (MMR) gene MSH2 cause Lynch syndromes I and II and sporadic colorectal cancers. Msh2(null) mice predominantly develop lymphoma and do not accurately recapitulate the colorectal cancer phenotype.

METHODS

We generated and examined mice with a conditional Msh2 disruption (Msh2(LoxP)), permitting tissue-specific gene inactivation. ECMsh2(LoxP/LoxP) mice carried an EIIa-Cre transgene, and VCMsh2(LoxP/LoxP) mice carried a Villin-Cre transgene. We combined the VCMsh2(LoxP) allele with either Msh2(Delta7null) (VCMsh2(LoxP/null)) or Msh2(G674D) mutations (VCMsh2(LoxP/G674D)) to create allelic phase mutants. These mice were given cisplatin or 5-fluorouracil/leucovorin and oxaliplatin (FOLFOX), and their tumors were measured by magnetic resonance imaging.

RESULTS

Embryonic fibroblasts from ECMsh2(LoxP/LoxP) mice do not express MSH2 and are MMR deficient. Reverse transcription, polymerase chain reaction, and immunohistochemistry from VCMsh2(LoxP/LoxP) mice demonstrated specific loss of Msh2 messenger RNA and protein from epithelial cells of the intestinal tract. Microsatellite instability was observed in all VCMsh2 strains and limited to the intestinal mucosa. Resulting adenomas and adenocarcinomas had somatic truncation mutations to the adenomatous polyposis coli (Apc) gene. VCMsh2(LoxP/LoxP) mice did not develop lymphoma. Comparison of allelic phase tumors revealed significant differences in multiplicity and size. When treated with cisplatin or FOLFOX, tumor size was reduced in VCMsh2(LoxP/G674D) but not VCMsh2(LoxP/null) tumors. The apoptotic response to FOLFOX was partially sustained in the intestinal mucosa of VCMsh2(LoxP/G674D) animals.

CONCLUSIONS

Msh2(LoxP/LoxP) mice in combination with appropriate Cre recombinase transgenes have excellent potential for preclinical modeling of Lynch syndrome, MMR-deficient tumors of other tissue types, and use in drug development.

OBJECTIVE

Owing to the risks of serious and sustained toxicity, anticancer drugs such as cisplatin and irinotecan cannot be readily administered to patients with gastric cancer and severe peritoneal metastasis. Therefore, a standard chemotherapy regimen has yet to be established for these types of patients. This randomized study investigated the utility of sequential methotrexate and 5-fluorouracil therapy vs. 5-fluorouracil continuous infusion for gastric cancer with peritoneal metastasis.

METHODS

Eligible patients had radiologically confirmed peritoneal metastasis with intestinal stenosis, peritoneal tumor or ascites. Treatment with 5-fluorouracil continuous infusion (800 mg/m(2)/day, ci, d1-5, q4w) or methotrexate and 5-fluorouracil therapy (methotrexate, 100 mg/m(2), bolus infusion, followed 3 h later by 5-fluorouracil, 600 mg/m(2), bolus infusion, with leucovorin rescue, q1w) was continued until disease progression or unacceptable toxicity. The projected sample size was 236, providing 80% power to detect a 40% increase in median overall survival in methotrexate and 5-fluorouracil therapy with a one-sided α of 0.05.

RESULTS

All 237 randomized patients were included in the primary analysis. The methotrexate and 5-fluorouracil therapy arm was not superior to the 5-fluorouracil continuous infusion arm (median survival time, 9.4 months in the 5-fluorouracil continuous infusion arm, 10.6 months in the methotrexate and 5-fluorouracil therapy arm; hazard ratio, 0.94; 95% confidence interval, 0.72-1.22; one-sided P = 0.31). Frequencies of Grade 3 or higher neutropenia, Grade 3 or higher anorexia and treatment-related deaths were 0.9, 27.4 and 1.7%, respectively, in the 5-fluorouracil continuous infusion arm, and 31.9, 33.6 and 0.9%, respectively, in the methotrexate and 5-fluorouracil therapy arm.

CONCLUSIONS

Methotrexate and 5-fluorouracil therapy is not suitable for use as standard therapy for advanced gastric cancer with peritoneal metastasis.

BACKGROUND

The purpose of this study was to assess the efficacy and toxicity of irinotecan and 5-fluorouracil (5-FU) in primary refractory or relapsed locally advanced or metastatic oesophagogastric (O-G) carcinoma.

METHODS

Patients with documented progression on or within 3 months of chemotherapy were recruited between July 2000 and May 2002. Irinotecan (180 mg/m(2)) was given with 5-FU (400 mg/m(2) bolus) and leucovorin (folinic acid) (125 mg/m(2)) followed by 5-FU (1200 mg/m(2) infusion over 48 h) every 2 weeks. Response confirmed by computed tomography was assessed at 12 and 24 weeks.

RESULTS

Thirty-eight of 40 registered patients (95%) were assessable. Median follow-up was 9.3 months and median age was 59.0 years. Thirty-three patients (86.8%) had metastatic disease and 37 patients (97.4%) had previously received platinum-based chemotherapy. Overall response rate was 29% (95% confidence interval 15.4% to 45.9%) while an additional 34% had stable disease. Improvement in tumour-related symptoms included dysphagia 78.6%, reflux 60.0%, pain 54.5%, anorexia 64.3% and weight loss 72.7%. Grade 3/4 toxicities were anaemia 13.2%, neutropenia 26.4%, febrile neutropenia 5.2%, stomatitis 2.6%, nausea and vomiting 13.2% and diarrhoea 7.9%. Median failure-free survival was 3.7 months and median overall survival was 6.4 months.

CONCLUSIONS

5-FU/irinotecan is a valuable regimen for second-line treatment in 5-FU/platinum-resistant O-G carcinoma.

The circadian timing system controls drug metabolism and cellular proliferation over the 24 h through molecular clocks in each cell, circadian physiology, and the suprachiasmatic nuclei--a hypothalamic pacemaker clock that coordinates circadian rhythms. As a result, both the toxicity and efficacy of over 30 anticancer agents vary by more than 50% as a function of dosing time in experimental models. The circadian timing system also down-regulates malignant growth in experimental models and possibly in cancer patients. Programmable-in-time infusion pumps and rhythmic physiology monitoring devices have made possible the application of chronotherapeutics to more than 2000 cancer patients without hospitalization. This strategy first revealed the antitumor efficacy of oxaliplatin against colorectal cancer. In this disease, international clinical trials have shown a five-fold improvement in patient tolerability and near doubling of antitumor activity through the chronomodulated, in comparison to constant-rate, delivery of oxaliplatin and 5-fluorouracil-leucovorin. Here, the relevance of the peak time, with reference to circadian rhythms, of the chemotherapeutic delivery of these cancer medications for achieving best tolerability was investigated in 114 patients with metastatic colorectal cancer and in 45 patients with non-small cell lung cancer. The incidence of severe adverse events varied up to five-fold as a function of the choice of when during the 24 h the peak dose of the medications was timed. The optimal chronomodulated schedules corresponded to peak delivery rates at 1 a.m. or 4 a.m. for 5-fluorouracil-leucovorin, at 1 p.m. or 4 p.m. for oxaliplatin, and at 4 p.m. for carboplatin. Sex of patient was an important determinant of drug schedule tolerability. This finding is consistent with recent results from a chronotherapy trial involving 554 patients with metastatic colorectal cancer, where sex also predicted survival outcome from chronotherapy, but not conventional drug delivery. Ongoing translational studies, mathematical modeling, and technology developments are further paving the way for tailoring cancer chronotherapeutics to the main rhythmic characteristics of the individual patient. Targeting therapeutic delivery to the dynamics of the cross-talk between the circadian clock, the cell division cycle, and pharmacology pathways represents a new challenge to concurrently improve the quality of life and survival of cancer patients through personalized cancer chronotherapeutics.

OBJECTIVE

In mouse models of pancreatic cancer, IPI-926, an oral Hedgehog inhibitor, increases chemotherapy delivery by depleting tumor-associated stroma. This multicenter phase Ib study evaluated IPI-926 in combination with FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan, oxaliplatin) in patients with advanced pancreatic cancer.

METHODS

Patients were treated with once-daily IPI-926 plus FOLFIRINOX. A 3 + 3 dose escalation design was used, with cohort expansion at the maximum tolerated dose. A subset of patients underwent perfusion computed tomography to assess changes in tumor perfusion.

RESULTS

The maximum tolerated dose was identified 1 dose level below standard FOLFIRINOX. Common treatment-related adverse events included liver function test abnormalities, neuropathy, nausea/vomiting, and diarrhea. Objective response rate was high (67%), and patients receiving IPI-926 maintenance showed further declines in CA19-9 levels even after FOLFIRINOX discontinuation. Treatment did not result in consistent increases in tumor perfusion. The study closed early when a separate phase II trial of IPI-926 plus gemcitabine indicated detrimental effects of this combination.

CONCLUSIONS

This is the first study to demonstrate the feasibility of using FOLFIRINOX as the chemotherapeutic backbone in a clinical trial design. Although robust antitumor activity and acceptable safety were observed with the addition of IPI-926 to this regimen, future development of Hedgehog inhibitors in pancreatic cancer seems unlikely.

OBJECTIVE

To compare chemotherapy alone with chemoradiation therapy in stage III-IV(M0) gastric cancer treated with R0 gastrectomy and D2 lymph node dissection.

METHODS

The chemotherapy arm received 5 cycles of fluorouracil and leucovorin (FL), and the chemoradiation therapy arm received 1 cycle of FL, then radiation therapy of 45 Gy concurrently with 2 cycles of FL, followed by 2 cycles of FL. Intent-to-treat analysis and per-protocol analyses were performed.

RESULTS

Between May 6, 2002 and June 29, 2006, a total of 90 patients were enrolled. Forty-four were randomly assigned to the chemotherapy arm and 46 to the chemoradiation therapy arm. Treatment was completed as planned by 93.2% of patients in the chemotherapy arm and 87.0% in the chemoradiation therapy arm. Overall intent-to-treat analysis showed that addition of radiation therapy to chemotherapy significantly improved locoregional recurrence-free survival (LRRFS) but not disease-free survival. In subgroup analysis for stage III, chemoradiation therapy significantly prolonged the 5-year LRRFS and disease-free survival rates compared with chemotherapy (93.2% vs 66.8%, P=.014; 73.5% vs 54.6%, P=.056, respectively).

CONCLUSIONS

Addition of radiation therapy to chemotherapy could improve the LRRFS in stage III gastric cancer treated with R0 gastrectomy and D2 lymph node dissection.

OBJECTIVE

Panitumumab is a fully human monoclonal antibody directed against the epidermal growth factor receptor and is indicated for patients with metastatic colorectal cancer (mCRC) who have experienced disease progression after standard chemotherapy. We conducted this phase II study to assess the ability of panitumumab to be administered with first-line irinotecan-containing regimens in patients with mCRC.

METHODS

This was a 2-part multicenter study of panitumumab 2.5 mg/kg weekly with irinotecan, 5-fluorouracil (5-FU), and leucovorin. Part 1 used bolus 5-FU (IFL), and part 2 used infusional 5-FU (FOLFIRI). Tolerability (measured by grade 3/4 diarrhea) was the primary endpoint. Objective response, progression-free survival, overall survival, and safety were also examined.

RESULTS

Nineteen patients in part 1 and 24 patients in part 2 received panitumumab plus chemotherapy. Grade 3/4 diarrhea occurred in 11 patients (58%) in part 1 and 6 patients (25%) in part 2. All patients had a skin-related toxicity (no grade 4 events). Objective response rates were 46% in part 1 and 42% in part 2. Disease control rates were 74% in part 1 and 79% in part 2. Median progression-free survival (95% confidence interval) was 5.6 months (4.4-8.3 months) for part 1 and 10.9 months (7.7-22.5 months) for part 2. Median overall survival (95% confidence interval) was 17 months (13.7 months to not estimable) for part 1 and 22.5 months (14.4 months to not estimable) for part 2.

CONCLUSIONS

In patients with mCRC, panitumumab/IFL was not well tolerated. Panitumumab/FOLFIRI was well tolerated, showed promising activity, and is undergoing further investigation.

Oral capecitabine (Xeloda) is an effective drug with favourable safety in adjuvant and metastatic colorectal cancer. Oxaliplatin-based therapy is becoming standard for Dukes' C colon cancer in patients suitable for combination therapy, but is not yet approved by the UK National Institute for Health and Clinical Excellence (NICE) in the adjuvant setting. Adjuvant capecitabine is at least as effective as 5-fluorouracil/leucovorin (5-FU/LV), with significant superiority in relapse-free survival and a trend towards improved disease-free and overall survival. We assessed the cost-effectiveness of adjuvant capecitabine from payer (UK National Health Service (NHS)) and societal perspectives. We used clinical trial data and published sources to estimate incremental direct and societal costs and gains in quality-adjusted life months (QALMs). Acquisition costs were higher for capecitabine than 5-FU/LV, but higher 5-FU/LV administration costs resulted in 57% lower chemotherapy costs for capecitabine. Capecitabine vs 5-FU/LV-associated adverse events required fewer medications and hospitalisations (cost savings pound3653). Societal costs, including patient travel/time costs, were reduced by >75% with capecitabine vs 5-FU/LV (cost savings pound1318), with lifetime gain in QALMs of 9 months. Medical resource utilisation is significantly decreased with capecitabine vs 5-FU/LV, with cost savings to the NHS and society. Capecitabine is also projected to increase life expectancy vs 5-FU/LV. Cost savings and better outcomes make capecitabine a preferred adjuvant therapy for Dukes' C colon cancer. This pharmacoeconomic analysis strongly supports replacing 5-FU/LV with capecitabine in the adjuvant treatment of colon cancer in the UK.

OBJECTIVE

Regulation of epidermal growth factor receptor (EGFR) signaling pathways may play a relevant role in determining the activity of cetuximab therapy in patients with metastatic colorectal cancer (MCRC). We investigated possible associations between genetic variants and clinical outcomes of MCRC patients treated with cetuximab-irinotecan salvage therapy.

METHODS

Patients who underwent cetuximab-irinotecan salvage therapy after disease progression during or after first-line bolus/infusional fluorouracil, leucovorin, and oxaliplatin chemotherapy and a second-line irinotecan-based regimen were considered eligible for analysis of polymorphisms with putative influence on cetuximab-related pathways. Epidermal growth factor (EGF) 61A>G, EGF receptor (EGFR) 216G>T, EGFR 497G>A, EGFR intron-1 (CA)(n) dinucleotide short (S)/long (L) variant, cyclin-D1 870A>G, immunoglobulin-G fragment-C receptors RIIIa 158G>T, and RIIa 131G>A were studied for a possible association with overall survival (OS) as the primary end point. Additional analyses were addressed at possible associations among polymorphisms and EGFR expression, toxicity, and response.

RESULTS

In 110 assessable patients, significant association with favorable OS was observed for EGFR intron-1 S/S and EGF 61 G/G genotypes. In the multivariate model, EGFR intron-1 S/S and EGF 61 G/G genotypes showed a hazard ratio of 0.41 (95% CI, 0.21 to 0.78; P = .006) and 0.44 (95% CI, 0.23 to 0.84; P = .01), respectively. EGFR intron-1 S/S carriers showed more frequent G2-G3 skin toxicity (chi(2) test = 12.7; P = .001) and treatment response (chi(2) test = 9.45; P = .008) than EGFR intron-1 L/L carriers.

CONCLUSIONS

Although additional studies are required for confirmation, our findings could optimize the use of cetuximab in MCRC patients.

BACKGROUND

Carcinoma of the biliary system is a rare tumor entity, and patients with advanced disease face a dismal prognosis. Because of the absence of standard chemotherapy for advanced biliary carcinoma, we have performed two consecutive studies to evaluate the clinical potential of 5-fluorouracil, leucovorin and mitomycin C as well as the novel antimetabolite gemcitabine in this disease.

METHODS

A total of 39 consecutive patients suffering from locally inoperable or metastatic biliary cancer were enrolled in the study between March 1994 and October 1997. Twenty patients were treated with leucovorin 200 mg/m2 and 5-FU 400 mg/m2, both given as intravenous bolus on days 1-4, and mitomycin C 8 mg/m2 on day 1 (group A). Treatment cycles were repeated every 28 days. The second cohort included 19 patients, who received gemcitabine 1200 mg/m2 on days 1, 8 and 15 with a 2-week interval before the next treatment cycle (group B). Treatment was continued for a maximum of 6 cycles in the absence of progressive disease in both groups, and endpoints of the study were responses rates, survival and toxicity.

RESULTS

In group A, 5 patients (25%) had a partial response (PR), 6 additional patients (30%) had stable disease (SD) and 9 patients (45%) progressed during treatment. The median survival was 9.5 months (range, 3-14.5) with the median time to progression being 4 months (range, 3-9). In group B, 3 patients achieved a PR (16%), 4 showed SD (21%), while the remaining 12 patients had progressive disease. A median survival of 6.5 months (range, 2-11.5) was obtained, and the median time to progression was 2.5 months (range, 1-6+). Toxicity was generally mild in both treatment arms, 6 patients in group A required dose reductions, while no dose adaptation had to be performed for gemcitabine.

CONCLUSIONS

Our data suggest that treatment of advanced biliary cancer is feasible and can be safely performed with both regimens applied in our study. While administration of gemcitabine has resulted in only mild toxicities, its exact impact on the management of advanced biliary cancer should be evaluated in a controlled trial.

The European Organisation for Research and Treatment of Cancer (EORTC) 22921 four-arm randomised trial questioned the value of preoperative chemoradiation (XRT-CT) versus preoperative radiation (XRT) and the value of additional postoperative chemotherapy (CT) versus none in T3-T4 M0 resectable rectal cancer patients. We report on the preoperative toxicity, treatment compliance and early deaths (all deaths up to 30 days after surgery) of the two treatment modalities in patients who were entered into trial before January 2001. In the XRT Group (group A), patients received 45 Gy, 25 fractions over 5 weeks. In the XRT-CT Group (group B), two 5-day courses of CT were added to the first and fifth weeks of XRT. For each CT course: 5-fluorouracil (5-FU) 350 mg/m2/day and Leucovorin (LV) 20 mg/m2/day were given. 398 and 400 patients started treatment in groups A and B, respectively. Grade 2+acute diarrhoea occurred in 17.3 and 34.3% of patients in groups A and B, respectively (P<0.005). The other side-effects remained unchanged or were only marginally increased. The compliance with RT was 98.5 and 95.5% in groups A and B, respectively. In group B, 78.7 and 71.1% of the patients received 95-105% of the planned CT doses at the first and second courses, respectively. 6 patients died preoperatively, 2 from toxicity in group B. 8 patients (1%) died within the 30 days after surgery in both groups. At the doses recommended in the protocol, the addition of 5-FU-LV to preoperative XRT slightly increased the amount of acute toxicity. However, the compliance with the radiation protocol or the feasibility of surgery did not decrease.

Fas is expressed constitutively in colonic epithelial cells and is also expressed in colon carcinomas and in cultured colon carcinoma cell lines. However, the potential role of Fas signaling in mediating apoptosis in cells of this type remains unknown. We have developed human colon carcinoma cell models deficient in thymidylate synthase that demonstrate acute (TS- cells) or delayed (Thy4 cells) apoptosis following DNA damage induced by thymineless stress. Complete protection of cells from acute apoptosis and prolongation of delayed apoptosis was obtained following exposure to the NOK-1 monoclonal antibody (inhibitory to Fas signaling) during the period of dThd deprivation. These results suggested that apoptosis induced by thymineless stress was regulated by autocrine signaling via Fas-FasL interactions. Fas expression was high in both TS- and Thy4 cells. However, FasL, undetectable in synchronous cultures, was up-regulated in TS- cells at 48 hr, when cells were undergoing acute apoptosis, and in Thy4 cells at 96 hr, correlating with the delayed onset of thymineless death. FasL expression also correlated with acute apoptosis induced in parental GC3/cl cells, commencing at 48 hr, following thymidylate synthase inhibition by 5-fluorouracil/leucovorin exposure. Fas-mediated apoptosis induced by the cytotoxic anti-Fas monoclonal antibody CH-11 was inhibited following adenoviral delivery of a Bcl-2 cDNA, and Bcl-2 also protected cells from acute apoptosis induced by dThd deprivation. Taken together, these data demonstrate a functional Fas system in these cultured colon carcinoma cell models, and they demonstrate that Fas-FasL interactions can link DNA damage induced by thymineless stress to the apoptotic machinery of colon carcinoma cells.

Recent advances in the treatment of colorectal cancer (CRC) include the incorporation of new drugs to treat a disease where only one drug was known to be active. Oxaliplatin and irinotecan have been incorporated into 5-fluorouracil (5-FU)-based regimens where they have increased response rates and survival. Targeted therapies against the epidermal growth factor pathway and the vascular endothelial growth factor (VEGF) pathway are also on the forefront of oncology research, and are beginning to play a role in the treatment of CRC. Current research efforts are trying to optimize the integration of targeted therapies into chemotherapy regimens such as IFL (irinotecan/bolus 5-FU/leucovorin [LV]), FOLFIRI (irinotecan/infusional 5-FU/LV), and FOLFOX (oxaliplatin/infusional 5-FU/LV). In this article, the incorporation of the monoclonal antibody bevacizumab into the IFL regimen will be reviewed in detail. Bevacizumab targets VEGF-A, an important angiogenesis signaling factor commonly expressed in metastatic CRC. The addition of bevacizumab to the IFL regimen significantly increased response rates, median time to progression, and overall survival in patients receiving first-line treatment for CRC, thus leading the Food and Drug Administration to approve bevacizumab for the treatment of CRC in combination with 5-FU-based regimens. Bevacizumab treatment is associated with an increased rate of hypertension. In addition, there may be slight (1%-2%) but relevant increased risks related to gastrointestinal perforations and cardiovascular events. A modest increased risk of wound healing complications was observed in patients who underwent surgery while still receiving, or shortly after receiving, bevacizumab. Bevacizumab plus 5-FU is also a highly active first-line regimen. The role of bevacizumab with other first-line combination regimens, as well as its activity in the second-line setting, is now being determined by ongoing clinical trials.

Purpose The standard of care for second-line therapy in patients with advanced pancreatic cancer after gemcitabine-based therapy is not clearly defined. The CONKO-003 phase III study reported a survival benefit with second-line fluorouracil (FU) and oxaliplatin using the oxaliplatin, folinic acid, and FU (OFF) regimen. 1 PANCREOX was a phase III multicenter trial to evaluate the benefit of FU and oxaliplatin administered as modified FOLFOX6 (mFOLFOX6; infusional fluorouracil, leucovorin, and oxaliplatin) versus infusional FU/leucovorin (LV) in this setting. Patients and Methods Patients with confirmed advanced pancreatic cancer who were previously treated with gemcitabine therapy and with an Eastern Cooperative Oncology Group performance status of 0-2 were eligible. A total of 108 patients were randomly assigned to receive biweekly mFOLFOX6 or infusional FU/LV until progression. Progression-free survival (PFS) was the primary end point. Results Baseline patient characteristics were similar in both arms. No difference was observed in PFS (median, 3.1 months v 2.9 months; P = .99). Overall survival (OS) was inferior in patients assigned to mFOLFOX6 (median, 6.1 months v 9.9 months; P = .02). Increased toxicity was observed with the addition of oxaliplatin, with grade 3/4 adverse events occurring in 63% of patients who received mFOLFOX6 and 11% of those who received FU/LV. More patients in the mFOLFOX6 arm withdrew from study due to adverse events than in the FU/LV arm (20% v 2%), whereas the use of postprogression therapy was significantly higher in the FU/LV arm (25% v 7%; P = .015). No significant differences were observed in time to deterioration on the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 global health scale. Conclusion No benefit was observed with the addition of oxaliplatin, administered as mFOLFOX6, versus infusional FU/LV in patients with advanced pancreatic cancer previously treated with first-line gemcitabine.

Thymidylate synthase is an important target for both fluorinated pyrimidines and for new folate analogues. Resistance to 5-fluorouracil (5FU) can be related to insufficient inhibition of thymidylate synthase. The 5FU-nucleotide FdUMP induces inhibition of thymidylate synthase which is enhanced and retained for longer in the presence of increased folate pools, for which leucovorin is a precursor. In a murine model system, 5FU treatment caused a 4-fold induction of thymidylate synthase levels which may have contributed to resistance. Addition of leucovorin to this treatment prevented this induction and increased the antitumour effect 2-3-fold. In the clinical setting, 5FU administration to patients resulted in approximately 50% inhibition of TS after 48 h. The combination with leucovorin resulted in a more pronounced inhibition after 48 h (approximately 70%). A significant relationship was observed with outcome of treatment; when thymidylate synthase levels were high and inhibition was low, no response was observed. A separate study showed that low thymidylate synthase levels appeared to be an independent prognostic factor for adjuvant therapy.

OBJECTIVE

To describe our experience with a bolus injection of 5-fluorouracil and leucovorin (FL) vs. capecitabine in terms of radiologic and pathologic findings in preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer.

METHODS

The study enrolled 278 patients scheduled for preoperative CRT using two protocols with different chemotherapeutic regimens. Pelvic radiotherapy (50.4 Gy) was delivered concurrently with FL (n = 145) or capecitabine (n = 133). Surgery was performed 6 weeks after CRT completion. Tumor responses to CRT were measured using both radiologic and pathologic examination. Magnetic resonance volumetry was performed at the initial workup and just before surgery after completion of preoperative CRT. Post-CRT pathology tests were used to determine tumor stage and regression.

RESULTS

Radiologic examination showed that tumor volume decreased by 68.2% +/- 20.5% in the FL group and 68.3% +/- 22.3% in the capecitabine group (p = 0.970). Postoperative pathologic T stage determination showed that downstaging occurred in 44.3% of FL and 49.9% of capecitabine patients (p = 0.571). The tumor regression grades after CRT were Grade 1 (minimal response) in 22.6% and 21.0%, Grade 2 (moderate response) in 53.2% and 50.0%, Grade 3 (near-complete response) in 12.9% and 12.9%, and Grade 4 (complete response) in 11.3% and 16.1% of the FL and capecitabine groups, respectively (p = 0.758).

CONCLUSIONS

In the present study, the radiologic and pathologic findings did not reveal significant differences in short-term tumor responses between preoperative FL and capecitabine CRT for locally advanced rectal cancer. Long-term results and a prospective randomized trial are needed.

The influence of MSI on treatment outcome of colorectal cancers remains unclear and deserves further investigation. We recruited 244 patients with stage IV sporadic colorectal cancers for our study, based on appropriate eligibility criteria. Patients were nonrandomly allocated to 2 treatment groups of either with or without high-dose 5-FU plus leucovorin chemotherapy (HDFL, 5-FU 2,600 mg/m(2) leucovorin 300 mg/m(2) maximum 500 mg). Each treatment group was further divided into 2 subgroups according to high-frequency MSI (MSI-H) status. MSI-H was defined as the appearance of MSI in at least 2 of the 5 examined chromosomal loci (BAT-25, BAT-26, D5S346, D2S123, D17S250). We compared clinicopathologic parameters, p53 overexpression and overall survival between the groups. In addition, 4 subgroups were identified as follows: MSI-H(+)HDFL(+), n = 35; MSI-H(-)HDFL(+), n = 134; MSI-H(+)HDFL(-), n = 17; MSI-H(-)HDFL(-), n = 58. There was no significant difference of background clinicopathologic data between the HDFL(+) and HDFL(-) treatment groups (p>> 0.05). Survival analyses indicated that the patients of subgroup MSI-H(+)HDFL(+) survived significantly longer than those of subgroup MSI-H(-)HDFL(+), with median survival times of 24 (95% CI 20.2-27.9) and 13 (95% CI 11.6-14.4) months, respectively (p = 0.0001, log-rank test). In contrast, in patients without chemotherapy, the prognosis was poor irrespective of MSI status, with median survival times of 7.0 (95% CI 4.6-9.4) and 7.0 (95% CI 6.1-7.9) months in the MSI-H(+)HDFL(-) and MSI-H(-)HDFL(-) subgroups, respectively (p = 0.8205, log-rank test). MSI-H cancers responded significantly better to HDFL (p = 0.001), with a mean response rate of 65.71% (95% CI 49.98-81.44%) in subgroup MSI-H(+)HDFL(+) compared to 35.07% (95% CI 26.99-43.15%) in subgroup MSI-H(-)HDFL(+). There appeared to be no preferential metastatic site where response to HDFL can be predicted based on the MSI status of the primary tumor. Toxicity to HDFL was similarly minimal between MSI-H(+) and MSI-H(-) patients (p>> 0.05). Multivariate analysis of all patients further indicated that MSI-H and chemotherapy were independent favorable prognostic parameters (p < 0.05). Thus, the better prognosis of stage IV sporadic colorectal cancers with MSI-H may be associated with better chemosensitivity, rather than lower aggressiveness in biologic behavior.

OBJECTIVE

The purpose of this prospective study was to determine the ability of fluorine-18 fluorodeoxyglucose positron emission tomography to assess extent of pathologically confirmed rectal cancer response to preoperative radiation and 5-fluorouracil-based chemotherapy.

METHODS

Patients with primary rectal cancer deemed eligible for preoperative radiation and 5-fluorouracil-based chemotherapy because of a clinically bulky or tethered tumor or endorectal ultrasound evidence of T3 and/or N1 were prospectively enrolled. Positron emission tomography and CT scans were obtained before preoperative radiation and 5-fluorouracil-based chemotherapy (5,040 cGy to the pelvis and 2 cycles of bolus 5-fluorouracil with leucovorin) and repeated four to five weeks after completion of radiation and 5-fluorouracil-based chemotherapy. In addition to routine pathologic staging, detailed assessment of rectal cancer response to preoperative radiation and 5-fluorouracil-based chemotherapy was performed independently by two pathologists. Positron emission tomography parameters studied included conventional measures such as standardized uptake value (average and maximum), positron emission tomography-derived tumor volume (size), and two novel parameters: visual response score and change in total lesion glycolysis.

RESULTS

Of 21 patients enrolled, prospective data (pretreatment and posttreatment positron emission tomography, and complete pathologic assessment) were available on 15 patients. All 15 demonstrated pathologic response to preoperative radiation and 5-fluorouracil-based chemotherapy. This was confirmed in 100 percent of the cases by positron emission tomography compared with 78 percent (7/9) by CT. In addition, one positron emission tomography parameter (visual response score) accurately estimated the extent of pathologic response in 60 percent (9/15) of cases compared with 22 percent (2/9) of cases with CT.

CONCLUSIONS

This pilot study demonstrates that fluorine-18 fluorodeoxyglucose positron emission tomography imaging adds incremental information to the preoperative assessment of patients with rectal cancer. However, further studies in a larger series of patients are needed to verify these findings and to determine the value of fluorine-18 fluorodeoxyglucose positron emission tomography in a preoperative strategy aimed at identifying patients suitable for sphincter-preserving rectal cancer surgery.

OBJECTIVE

Modest toxicity and possibly enhanced activity makes continuous-infusion fluorouracil (FU) an attractive alternative to FU plus leucovorin (FU/LV) for the adjuvant treatment of colorectal cancer. Intergroup trial 0153 (Southwest Oncology Group trial 9415) was developed to compare the efficacy of continuous-infusion FU (CIFU) plus levamisole to FU/LV plus levamisole in the adjuvant treatment of high-risk Dukes' B2 and C1 or C2 colon cancer.

METHODS

After surgery, patients were randomly assigned to CIFU 250 mg/m(2)/d for 56 days every 9 weeks for three cycles or FU 425 mg/m(2) and LV 20 mg/m(2) daily for 5 days every 28 to 35 days for six cycles. All patients received levamisole 50 mg tid for 3 days every other week. The primary end point was overall survival (OS).

RESULTS

The study closed in December 1999 after an interim analysis demonstrated little likelihood of CIFU showing superiority to FU/LV within the stipulated hazard ratio. A total of 1,135 patients were registered. At least one grade 4 toxicity occurred in 39% of patients receiving FU/LV and 5% of patients receiving CIFU. However, almost twice as many patients receiving CIFU discontinued therapy early compared with those receiving FU/LV. The 5-year OS is 70% (95% CI, 66% to 74%) for FU/LV and 69% (95% CI, 64% to 73%) for CIFU. The corresponding 5-year disease-free survival (DFS) is 61% (95% CI, 56% to 65%) and 63% (95% CI, 59% to 68%), respectively. For all patients, 5-year OS is 83%, 74%, and 55%; 5-year DFS is 78%, 67%, and 47% for N0, N1, and N2-3, respectively.

CONCLUSIONS

CIFU had less severe toxicity but did not improve DFS or OS in comparison with bolus FU/LV.

Neutral red assay, as an index of cytotoxicity, has been applied to predictive screening of chemotherapeutic agents. Human hepatoma and melanoma tumor cells and normal melanocytes, keratinocytes, and fibroblasts were incubated for 2, 24, and 48 h with graded concentrations of cis-platinum (0.1 to 80 microM), doxorubicin (0.01 to 100 microM), and 5-fluorouracil (1 to 1000 microM). Cells were most sensitive after 48 h. Tumor cells, based on 50% toxicity values, were 2-4 times more sensitive than the normal cells, except for cis-platinum, where only melanoma cells, as compared to normal melanocytes, showed a marked difference in cytotoxic response. Methotrexate (1 to 10 microM) toxicity could be reversed in the presence of 100 microM of leucovorin. This sensitive, rapid, and economical assay is suitable for preclinical screening and drug development.

Patients with peritoneal or local metastases from colorectal cancer have a poor prognosis. However, aggressive treatments by debulking surgery and infusional intraperitoneal (i.p.) chemotherapy have been tried and appear to benefit selected patients. We assayed the effects of debulking surgery and i.p. chemotherapy with respect to survival and compared the results with matched control patients treated by intravenous (i.v.) chemotherapy. In all, 18 patients with peritoneal and/or local metastases from colorectal adenocarcinoma underwent debulking surgery followed by 5-fluorouracil (5-FU) 550 mg m(-2) day(-1) i.p. and leucovorin (LV) 60 mg m(-2) day(-1) i.v. The chemotherapy was started the day after surgery and was given daily for 6 days and repeated monthly for totally eight courses. The control patients, matched for age, gender, performance status and metastatic site, were randomly selected from controlled clinical chemotherapy trials and treated with i.v. 5-FU+LV or i.v. methotrexate+5-FU+LV. There was no treatment-related mortality. The median survival among i.p. patients was 32 months compared to 14 months in the control group. In all, 11 patients who underwent macroscopically radical surgery had a longer survival than those who were not radically operated (P=0.02). These results indicate that patients with peritoneal metastases and/or locally advanced cancers but without distant metastases may benefit from cytoreductive surgery combined with i.p. chemotherapy.

Interest in determining if leucovorin, known chemically as 5-formyltetra-hydrofolate, plays a role in one-carbon metabolism is reemerging. While investigations in the 1940s suggested it was an important donor of one-carbon units in folate-mediated biosynthetic reactions, studies between the 1950s and 1980s disproved this hypothesis and dismissed its presence in biological systems as artifactual. Recently, new data has focused attention on the possible biological function of this compound that is widely used in cancer chemotherapy.

High-dose methotrexate (HDMTX) with leucovorin (LV) rescue has been used as a therapeutic strategy in oncology for more than a decade. Administration of HDMTX results in tumoricidal plasma concentrations of the drug without significant host toxicity, provided that plasma MTX levels are monitored and LV rescue is properly administered. The original premise of LV rescue was that the provision of reduced folate to normal cells would circumvent the metabolic block produced by MTX and allow resumption of DNA synthesis, although the presumed therapeutic selectivity of leucovorin has not yet been adequately explained. Despite a strong pharmacologic rationale and a vast clinical experience, HDMTX with leucovorin rescue has not been shown to be unequivocally superior to conventional doses of MTX in any clinical situation except, perhaps, for treatment of osteogenic sarcoma and childhood acute leukemia. While HDMTX is an important component of effective treatment regimens for these diseases, its precise contribution to the success of these regimens remains undefined. Although HDMTX can theoretically overcome all known mechanisms of MTX resistance, no data exist to suggest that this can be accomplished in the clinic. Thus, this well-known but poorly understood treatment regimen must remain a subject of clinical investigation rather than a part of routine clinical practice.