Weight gain in women with breast cancer treated with adjuvant cyclophosphomide, methotrexate and 5-fluorouracil. Analysis of resting energy expenditure and body composition.

Background: Weight gain is a common side effect observed in women undergoing adjuvant chemotherapy for breast cancer. Among possible causes a direct effect of chemotherapy on metabolism has been proposed. Body composition variations after adjuvant chemotherapy suggest the occurrence of sarcopenic obesity, possibly due to ovarian failure. We investigated acute and chronic effects of adjuvant chemotherapy on body weight, resting energy expenditure (REE) and plasma catecholamines in a group of menopausal women.

Patients And Methods: Thirty menopausal women with stage I-II breast cancer were recruited for the study. We measured REE and respiratory quotient (RQ) and body composition at the beginning and after 3 and 6 months of adjuvant cyclophosphomide, methotrexate, and 5-fluorouracil (CMF). REE, RQ, and plasma catecholamines were assessed before and after each chemotherapy session. At each session food intake was also assessed in all patients, by a food diary. Seven patients out of the group of 30 were also evaluated after a placebo infusion (saline).

Results: A significant weight gain was observed in all women (70.5 +/- 3 v.s. 67.7 +/- 3 kg, p < 0.001), with increase in both fat-free mass (FFM) (45.2 +/- 1.5 v.s. 43.6 +/- 1.3 kg, p < 0.001) and fat-mass (FM) (25.3 +/- 1.7 v.s. 24.1 +/- 1.8 kg, p < 0.005). A decrease in REE and RQ was observed both during CMF and placebo infusion (p < 0.05). During acute CMF and placebo infusion a reduction of plasma levels of noradrenaline was observed at the first and last session. REE increased progressively during the study period.

Conclusions: CMF therapy apparently has no effect on REE either acutely or during a 6-month-period; the increased REE observed in the long-term is likely due to the concomitant increase in FFM. The lack of evidence of sarcopenic obesity, at variance with previous literature, is likely due to different patient selection.