BACKGROUND

The optimal fractionation schedule for whole-breast irradiation after breast-conserving surgery is unknown.

METHODS

We conducted a study to determine whether a hypofractionated 3-week schedule of whole-breast irradiation is as effective as a 5-week schedule. Women with invasive breast cancer who had undergone breast-conserving surgery and in whom resection margins were clear and axillary lymph nodes were negative were randomly assigned to receive whole-breast irradiation either at a standard dose of 50.0 Gy in 25 fractions over a period of 35 days (the control group) or at a dose of 42.5 Gy in 16 fractions over a period of 22 days (the hypofractionated-radiation group).

RESULTS

The risk of local recurrence at 10 years was 6.7% among the 612 women assigned to standard irradiation as compared with 6.2% among the 622 women assigned to the hypofractionated regimen (absolute difference, 0.5 percentage points; 95% confidence interval [CI], -2.5 to 3.5). At 10 years, 71.3% of women in the control group as compared with 69.8% of the women in the hypofractionated-radiation group had a good or excellent cosmetic outcome (absolute difference, 1.5 percentage points; 95% CI, -6.9 to 9.8).

CONCLUSIONS

Ten years after treatment, accelerated, hypofractionated whole-breast irradiation was not inferior to standard radiation treatment in women who had undergone breast-conserving surgery for invasive breast cancer with clear surgical margins and negative axillary nodes. (ClinicalTrials.gov number, NCT00156052.)

BACKGROUND

The international standard radiotherapy schedule for early breast cancer delivers 50 Gy in 25 fractions of 2.0 Gy over 5 weeks, but there is a long history of non-standard regimens delivering a lower total dose using fewer, larger fractions (hypofractionation). We aimed to test the benefits of radiotherapy schedules using fraction sizes larger than 2.0 Gy in terms of local-regional tumour control, normal tissue responses, quality of life, and economic consequences in women prescribed post-operative radiotherapy.

METHODS

Between 1999 and 2001, 2215 women with early breast cancer (pT1-3a pN0-1 M0) at 23 centres in the UK were randomly assigned after primary surgery to receive 50 Gy in 25 fractions of 2.0 Gy over 5 weeks or 40 Gy in 15 fractions of 2.67 Gy over 3 weeks. Women were eligible for the trial if they were aged over 18 years, did not have an immediate reconstruction, and were available for follow-up. Randomisation method was computer generated and was not blinded. The protocol-specified principal endpoints were local-regional tumour relapse, defined as reappearance of cancer at irradiated sites, late normal tissue effects, and quality of life. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN59368779.

RESULTS

1105 women were assigned to the 50 Gy group and 1110 to the 40 Gy group. After a median follow up of 6.0 years (IQR 5.0-6.2) the rate of local-regional tumour relapse at 5 years was 2.2% (95% CI 1.3-3.1) in the 40 Gy group and 3.3% (95% CI 2.2 to 4.5) in the 50 Gy group, representing an absolute difference of -0.7% (95% CI -1.7% to 0.9%)--ie, the absolute difference in local-regional relapse could be up to 1.7% better and at most 1% worse after 40 Gy than after 50 Gy. Photographic and patient self-assessments indicated lower rates of late adverse effects after 40 Gy than after 50 Gy.

CONCLUSIONS

A radiation schedule delivering 40 Gy in 15 fractions seems to offer rates of local-regional tumour relapse and late adverse effects at least as favourable as the standard schedule of 50 Gy in 25 fractions.

BACKGROUND

The international standard radiotherapy schedule for breast cancer treatment delivers a high total dose in 25 small daily doses (fractions). However, a lower total dose delivered in fewer, larger fractions (hypofractionation) is hypothesised to be at least as safe and effective as the standard treatment. We tested two dose levels of a 13-fraction schedule against the standard regimen with the aim of measuring the sensitivity of normal and malignant tissues to fraction size.

METHODS

Between 1998 and 2002, 2236 women with early breast cancer (pT1-3a pN0-1 M0) at 17 centres in the UK were randomly assigned after primary surgery to receive 50 Gy in 25 fractions of 2.0 Gy versus 41.6 Gy or 39 Gy in 13 fractions of 3.2 Gy or 3.0 Gy over 5 weeks. Women were eligible if they were aged over 18 years, did not have an immediate surgical reconstruction, and were available for follow-up. Randomisation method was computer generated and was not blinded. The protocol-specified principal endpoints were local-regional tumour relapse, defined as reappearance of cancer at irradiated sites, late normal tissue effects, and quality of life. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN59368779.

RESULTS

749 women were assigned to the 50 Gy group, 750 to the 41.6 Gy group, and 737 to the 39 Gy group. After a median follow up of 5.1 years (IQR 4.4-6.0) the rate of local-regional tumour relapse at 5 years was 3.6% (95% CI 2.2-5.1) after 50 Gy, 3.5% (95% CI 2.1-4.3) after 41.6 Gy, and 5.2% (95% CI 3.5-6.9) after 39 Gy. The estimated absolute differences in 5-year local-regional relapse rates compared with 50 Gy were 0.2% (95% CI -1.3% to 2.6%) after 41.6 Gy and 0.9% (95% CI -0.8% to 3.7%) after 39 Gy. Photographic and patient self-assessments suggested lower rates of late adverse effects after 39 Gy than with 50 Gy, with an HR for late change in breast appearance (photographic) of 0.69 (95% CI 0.52-0.91, p=0.01). From a planned meta-analysis with the pilot trial, the adjusted estimates of alpha/beta value for tumour control was 4.6 Gy (95% CI 1.1-8.1) and for late change in breast appearance (photographic) was 3.4 Gy (95% CI 2.3-4.5).

CONCLUSIONS

The data are consistent with the hypothesis that breast cancer and the dose-limiting normal tissues respond similarly to change in radiotherapy fraction size. 41.6 Gy in 13 fractions was similar to the control regimen of 50 Gy in 25 fractions in terms of local-regional tumour control and late normal tissue effects, a result consistent with the result of START Trial B. A lower total dose in a smaller number of fractions could offer similar rates of tumour control and normal tissue damage as the international standard fractionation schedule of 50 Gy in 25 fractions.

BACKGROUND

Radiotherapy prevents local recurrence of breast cancer after breast-conserving surgery. We evaluated the effect of a supplementary dose of radiation to the tumor bed on the rates of local recurrence among patients who received radiotherapy after breast-conserving surgery for early breast cancer.

METHODS

After lumpectomy and axillary dissection, patients with stage I or II breast cancer received 50 Gy of radiation to the whole breast in 2-Gy fractions over a five-week period. Patients with a microscopically complete excision were randomly assigned to receive either no further local treatment (2657 patients) or an additional localized dose of 16 Gy, usually given in eight fractions by means of an external electron beam (2661 patients).

RESULTS

During a median follow-up period of 5.1 years, local recurrences were observed in 182 of the 2657 patients in the standard-treatment group and 109 of the 2661 patients in the additional-radiation group. The five-year actuarial rates of local recurrence were 7.3 percent (95 percent confidence interval, 6.8 to 7.6 percent) and 4.3 percent (95 percent confidence interval, 3.8 to 4.7 percent), respectively (P<0.001), yielding a hazard ratio for local recurrence of 0.59 (99 percent confidence interval, 0.43 to 0.81) associated with an additional dose. Patients 40 years old or younger benefited most; at five years, their rate of local recurrence was 19.5 percent with standard treatment and 10.2 percent with additional radiation (hazard ratio, 0.46 [99 percent confidence interval, 0.23 to 0.89]; P=0.002). At five years in the age group 41 to 50 years old, no differences were found in rates of metastasis or overall survival (which were 87 and 91 percent, respectively).

CONCLUSIONS

In patients with early breast cancer who undergo breast-conserving surgery and receive 50 Gy of radiation to the whole breast, an additional dose of 16 Gy of radiation to the tumor bed reduces the risk of local recurrence, especially in patients younger than 50 years of age.

BACKGROUND

Standard curative schedules of radiotherapy to the breast deliver 25 fractions of 2.0 Gy over 5 weeks. In a randomised trial, we tested whether fewer, larger fractions were at least as safe and as effective as standard regimens. In this analysis, we assessed the long-term results of tumour control in the same population.

METHODS

In 1986-98, we randomly assigned 1410 women with invasive breast cancer (tumour stage 1-3 with a maximum of one positive node and no metastasis) who had had local tumour excision of early stage breast cancer to receive 50 Gy radiotherapy given in 25 fractions, 39 Gy given in 13 fractions, or 42.9 Gy given in 13 fractions, all given over 5 weeks. The primary endpoint was late change in breast appearance, which has been reported elsewhere. Here, we report ipsilateral tumour relapse, one of the secondary endpoints. Relapse was defined as any appearance of cancer in the irradiated breast. Analysis was by intention to treat.

RESULTS

After a median follow-up of 9.7 years (IQR 7.8-11.8) for the 838 (95%) patients who survived, the risk of ipsilateral tumour relapse after 10 years was 12.1% (95% CI 8.8-15.5) in the 50 Gy group, 14.8% (11.2-18.3) in the 39 Gy group, and 9.6% (6.7-12.6) in the 42.9 Gy group (difference between 39 Gy and 42.9 Gy groups, chi2 test, p=0.027). The sensitivity of breast cancer to dose per fraction was estimated to be 4.0 Gy (95% CI 1.0-7.8), similar to that estimated for the late adverse effects in healthy tissue from breast radiotherapy.

CONCLUSIONS

Breast cancer tissue is probably just as sensitive to fraction size as dose-limiting healthy tissues. If this finding is confirmed, radiotherapy schedules can be greatly simplified by the delivery of fewer, larger fractions without compromising effectiveness or safety, and possibly improving both.

BACKGROUND

Breast irradiation after lumpectomy is an integral component of breast-conserving therapy that reduces the local recurrence of breast cancer. Because an optimal fractionation schedule (radiation dose given in a specified number of fractions or treatment sessions over a defined time) for breast irradiation has not been uniformly accepted, we examined whether a 22-day fractionation schedule was as effective as the more traditional 35-day schedule in reducing recurrence.

METHODS

Women with invasive breast cancer who were treated by lumpectomy and had pathologically clear resection margins and negative axillary lymph nodes were randomly assigned to receive whole breast irradiation of 42.5 Gy in 16 fractions over 22 days (short arm) or whole breast irradiation of 50 Gy in 25 fractions over 35 days (long arm). The primary outcome was local recurrence of invasive breast cancer in the treated breast. Secondary outcomes included cosmetic outcome, assessed with the European Organisation for Research and Treatment of Cancer (EORTC) Cosmetic Rating System. All statistical tests were two-sided.

RESULTS

From April 1993 through September 1996, 1234 women were randomly assigned to treatment, 622 to the short arm and 612 to the long arm. Median follow-up was 69 months. Five-year local recurrence-free survival was 97.2% in the short arm and 96.8% in the long arm (absolute difference = 0.4%, 95% confidence interval [CI] = -1.5% to 2.4%). No difference in disease-free or overall survival rates was detected between study arms. The percentage of patients with an excellent or good global cosmetic outcome at 3 years was 76.8% in the short arm and 77.0% in the long arm; the corresponding data at 5 years were 76.8% and 77.4%, respectively (absolute difference = -0.6%, 95% CI = -6.5% to 5.5%).

CONCLUSIONS

The more convenient 22-day fractionation schedule appears to be an acceptable alternative to the 35-day schedule.

OBJECTIVE

Unlike squamous carcinomas, breast adenocarcinoma may be as sensitive to fraction size as late dose-limiting normal tissues. If so, fewer larger fractions would be as safe and effective as regimens based on 2.0 Gy fractions. The first step is to test the effects of radiotherapy fractions >2.0 Gy on late normal tissue responses in the breast after tumour excision and radiotherapy for early breast cancer.

METHODS

One thousand four-hundred and ten women with T1-3 N0-1 M0 invasive breast cancer were randomised between 1986-98 into one of three radiotherapy regimens after local tumour excision of early stage breast cancer; 50 Gy in 25 fractions (F) vs two dose levels of a test schedule giving 39 or 42.9 Gy in 13 F over 5 weeks. Fraction sizes were 2.0, 3.0 and 3.3 Gy, respectively. The primary endpoint was late change in breast appearance compared to post-surgical appearance scored from annual photographs blinded to treatment allocation. Secondary endpoints included palpable breast induration (fibrosis) and ipsilateral tumour recurrence.

RESULTS

After a minimum 5-year follow up, the risk of scoring any change in breast appearance after 50 Gy/25 F, 39 Gy/13 F and 42.9 Gy/13 F was 39.6, 30.3 and 45.7%, from which an alpha/beta value of 3.6 Gy (95% CI 1.8-5.4) is estimated. The alpha/beta value for palpable breast induration was 3.1 Gy (95% CI 1.8-4.4).

CONCLUSIONS

An alpha/beta value of around 3 Gy for late normal tissue changes in the breast is derived from the estimated equivalence of 41.6 Gy in 13 fractions and 50 Gy in 25 fractions over 5 weeks, in line with trial predictions.

Hypofractionation is attractive for whole- or partial-breast irradiation because it permits treatment to be given with fewer fractions in a shorter period of time and at less cost. A number of cohort studies suggest that hypofractionation may be given to the whole breast safely and with good local control. Recent randomized trials have confirmed that hypofractioned whole-breast irradiation is equivalent to more conventional whole-breast irradiation with respect to local recurrence and cosmetic outcome. Recently, there has been a renewed interest in hypofractionation for the delivery of partial-breast irradiation using a number of techniques including high-dose rate brachytherapy, 3-dimensional conformal radiation using external-beam techniques, and intraoperative therapy. Early cohort studies report good local control and acceptable morbidity. Randomized trials are now underway to compare this approach to conventional whole-breast irradiation.

OBJECTIVE

To report the acute and preliminary data on late toxicity of a pilot study of boost with electron intraoperative therapy followed by hypofractionated external beam radiotherapy (HEBRT) of the whole breast.

METHODS

Between June 2004 and March 2007, 211 women with a diagnosis of early-stage breast cancer were treated with breast-conserving surgery. During surgery, an electron intraoperative therapy boost of 12 Gy was administered to the tumor bed. Adjuvant local treatment was completed with HEBRT, consisting of a course of 13 daily fractions of 2.85 Gy to the whole breast to a total dose of 37.05 Gy. Acute toxicity of the breast was evaluated at the end of HEBRT and at 1 month of follow-up. Late toxicity was recorded at 6 and 12 months of follow-up.

RESULTS

We report the data from 204 patients. The maximal acute skin toxicity was observed at the end of HEBRT (182 patients evaluable) with 7 (3.8%) Grade 3, 52 (28.6%) Grade 2, 123 (67.6%) Grade 1, and no Grade 0 or Grade 4 cases. A total of 108 patients were evaluated for late toxicity. The recorded late skin toxicity was Grade 4 in 1 patient (0.9%), Grade 3 in 1 patient, and Grade 2 or less in 106 patients (98.2%).

CONCLUSIONS

The results of this study have shown that electron intraoperative therapy followed by HEBRT allows for the delivery of a high dose to the tumor bed and an adequate dose to the whole breast. This treatment is feasible, compliance is high, and the rate of acute toxicity and the preliminary data on chronic toxicity seem acceptable.

Conventional radiotherapy after breast-conserving therapy is confined to 50-55 Gy external beam radiation therapy (EBRT) to the whole breast and 10-16 Gy external boost radiation to the tumour bed or brachytherapy to the tumour bed. Local recurrence rate after breast-conserving surgery varies between 5 and 18%. External boost radiation can partially miss the tumour bed and therefore can result in local failure. Intra-operative radiotherapy (IORT) as a high precision boost can prevent a 'geographical miss'. From October 1998 to December 2000, 156 patients with stage I and stage II breast cancer were operated upon in a dedicated IORT facility. After local excision of the tumour, the tumour bed was temporarily approximated by sutures to bring the tissue in the radiation planning target volume. A single dose of 9 Gy was applied to the 90% reference isodose with energies ranging from 4 to 15 MeV, using round applicator tubes 4-8 cm in diameter. After wound healing, the patients received additional 51-56 Gy EBRT to the whole breast. No acute complications associated with IORT were observed. In 5 patients, a secondary mastectomy had to be performed because of tumour multicentricity in the final pathological report or excessive intraductal component. 2 patients developed rib necroses. In 7 patients, wound healing problems occurred. After a mean follow-up of 18 months, no local recurrences were observed. Cosmesis of the breast was very good and comparable to patients without IORT. Preliminary data suggest that IORT given as a boost after breast-conserving surgery could be a reliable alternative to conventional postoperative fractionated boost radiation by accurate dose delivery and avoiding geographical misses, by enabling smaller treatment volumes and complete skin-sparing and by reducing postoperative radiation time by 7-14 days.

Aim of this study is to show that ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery can be reduced by proper surgery and modern radiotherapy techniques. Three hundred and seventy eight women with stage I or II breast cancer had breast conserving surgery and received 51-56.1 Gy of postoperative radiation to the whole breast in 1.7 Gy fractions, but patients received different boost strategies. Group 1 (n = 188) received electron boost radiation of 12 Gy subsequent to the irradiation to the whole breast, group 2 (n = 190) received intraoperative electron boost radiation of 9 Gy directly to the tumor bed, followed by whole breast irradiation. After a median follow up period of 81.0 months in group 1 and a median follow up period of 51.1 months in group 2, 12 IBTRs (6.4%) could be observed in group 1 and no IBTR could be observed in group 2 (0.0%). The 5-year actuarial rates of IBTR were 4.3% (95% CI, 1.9-8.3%) and 0.0% (95% CI, 0.0-1.9%), respectively (p = 0.0018). The 5-year actuarial rates of distant recurrence were 8.6% (95% CI, 4.9-13.5%) and 4.2% (95% CI, 1.8-8.2%), respectively (p = 0.08). The 5 year disease-free survival rates were 90.9% (95% CI, 85.8-94.7%) in group 1 and 95.8% (95% CI, 91.8-98.2%) in group 2 (p = 0.064). Immediate IORT-boost and whole breast irradiation yields excellent local control at 5 years, and was associated with a statistically significant decreased rate of IBTR compared with a similar cohort of patients treated with whole breast irradiation and conventional electron boost.