Cutting Chemo Dose in Some Obese Patients Affects Survival
Concerns about toxicity in obese breast cancer patients unsubstantiated
THURSDAY, Sep. 1 (HealthDay Professional Briefing) -- Obese women with estrogen receptor-negative breast cancer who are given a reduced dose of chemotherapy have a worse outcome than other patients, according to a research letter published online August 24 in The Lancet.
Marco Colleoni, of the European Institute of Oncology in Italy, and colleagues surveyed data from four randomized trials that assessed adjuvant classical CMF (cyclophosphamide, methotrexate, and 5-fluorouracil). The trials were done in a variety of countries between 1978 and 1993.
They found that obese patients with estrogen receptor-negative breast cancer who received 85% or less of the expected dose in the first course of chemotherapy had "a significantly worse outcome" than patients who received more than 85% (disease free survival, 0.68; overall survival, 0.72). However, this was not true in estrogen receptor-positive cohort (disease free survival, 1.16; overall survival, 1.16). Overall, 39% of obese patients received a lower dose in the first course compared with 16% of patients with normal or intermediate body mass index.
Although chemotherapy doses are often reduced in obese patients because of concerns about toxicity, there is conflicting data about the optimum dose intensity for relapse-free survival among these patients. "Our findings suggest that for women with ER-absent or ER-low tumours, reduction in chemotherapy doses should be avoided," the researchers conclude.