Body weight loss as an indicator of breast cancer recurrence.

Body weight loss (BWL), a major prognostic factor in breast cancer, was included as a parameter to be monitored in the recent breast cancer surveillance guidelines of the American Society of Clinical Oncology. The aim of this work was prospectively to evaluate BWL as an indicator of breast cancer recurrence. Body weight was measured every 2 months for 10.4+/-3.7 (SD) months in 109 disease-free breast cancer patients in stage II node-positive and stage III disease. The correlation between unexplained BWL and recurrence was studied. Attempts were made to define the limits in weight variations among disease-free patients beyond which recurrence could be suspected. Unexplained BWL was observed in 16/19 (84%) patients developing recurrence, versus 9/90 (10%) patients remaining disease-free. There was a significant (p < 0.001) correlation between BWL and recurrence. BWL anticipated the diagnosis of recurrence by 6 (range 4-12) months. Based on the average percentage weight variation +/- 2 SD (95% confidence interval) of the disease-free group, the limits for BWL beyond which recurrence could be suspected were a 5.8% decrease in the last 6 months, 3.6% in the last 2 months or 3.0% of the patient's mean weight. However, because of the large variation in the amplitude of individual weight oscillations among disease-free patients (from < 0.5% to > 5.9% of the mean weight), individual limits derived from the patient's own body weight curve seemed more reliable. The results suggest that unexplained BWL is a valuable indicator of incipient breast cancer recurrence. Careful monitoring of body weight in breast cancer patients during follow-up is encouraged.