BACKGROUND

Tumour necrosis factor-alpha (TNF) has been regarded as a potential mediator of cancer cachexia. Assessment of TNF circulating levels in cancer patients and their correlation with weight loss has led to controversial results.

METHODS

We measured TNF circulating levels in 28 patients with gastrointestinal cancer and 29 controls with benign gastrointestinal diseases at different times (08.00 h, 14.00 h, 20.00 h) before operation.

RESULTS

TNF activity was not detected in any of controls at any times. In cancer patients, TNF circulating levels were detectable in 18 cases (64.3%) and appeared to be discontinuous. TNF levels above the limit of detection were present in 15 patients (53.6%) at 08.00 h, in 14 (50%) at 014.00 h and in nine (32.1%) at 20.00 h. Mean TNF levels were 14.3 +/- 4 pg mL(-1) at 08.00 h, 16.7 +/- 4.6 pg mL(-1) at 14.00 h (P = 0.05) and 18.5 +/- 10.2 pg mL(-1) at 20.00 h (P < 0.05 vs. 08.00 h and 14.00 h). According to Spearman's analysis, the sum of TNF concentrations at the three times significantly correlated with the severity of weight loss (Spearman's correlation coefficient = - 0.420; P = 0.026). TNF concentrations were consistently and significantly higher in patients with severe weight loss than in those with moderate or light weight loss at 08.00 h (26.3 +/- 8.3, 8.9 +/- 4.2, 3.8 +/- 2.1, respectively; P = 0.04 at one-way ANOVA). TNF levels were higher in anorectic than in nonanorectic patients at any hour, but the differences were not statistically significant.

CONCLUSIONS

The present study demonstrates that TNF is intermittently or discontinuously detectable in patients with gastrointestinal cancer and that its levels correlate with the severity of weight loss.