Comparative evaluation of two methods of chemotherapy dose calculation according to body surface area and body mass index in obese females with breast cancer.

Abstract

678 Background: Obese patients experience planned or unplanned reduction in chemotherapy dose. There seems to be a consistent tendency to underdose obese patients. Methods: In Alexandria Clinical Oncology Department, from October 2004 to June 2005, 120 obese female breast cancer patients were prospectively recruited, signed IRB approved informed consent and randomized. A woman was classified as obese if her body surface area (BSA) > 2 and/or body mass index >/= 27.3 kg/m2. They received adjuvant FAC chemotherapy calculated according to either the actual (group I) or ideal (group II) BSA. Ideal BSA was calculated according to ideal body weight. The patients were followed prospectively during chemotherapy and for 60 months. Results: Both groups were comparable regarding age (mean 47.5 years), weight (mean 85.5 kg), height (mean 157 cm), menopausal status, hormonal receptors' status, PS, grade, and stage without any statistical difference. The most common acute lab toxicity was the hematological toxicity that was statistically significant on comparing the hemoglobin level (HB) between the first cycle and sixth cycle (p > 0.002) in group I but of no significance in group II. There was an overall statistical significant difference between group I and II as regard the HB level (p < 0.0001), WBCs counts (p > 0.002) and liver function test -ALT level- (p < 0.0001). The same pattern was also noted between the 2 groups as regards renal toxicity, gastrointestinal toxicity, nail discoloration, and hair loss. After 60 months of follow up, there was no statistical significant difference as regards the disease-free survival (mean 46.48 months in group I versus 49.3 months in group II) or treatment failure (19 patients -31.7%- in group I versus 18 patients -30%- in group II with p > 0.843). Conclusions: There was a trend towards a higher toxicity profile in the obese females who received FAC chemotherapy for early stage breast cancer dosed according to the actual BSA. However, no significant differences as regard the treatment failure or disease free survival after 60 months of follow up. We believe that this innovative method used in calculating the chemotherapy dose is less toxic, safer and relatively effective. No significant financial relationships to disclose.