Capping the dose of paclitaxel in endometrial cancer patients: Does this affect clinical outcome?

Abstract

e16563 Background: Various protocols recommend capping chemotherapy dosing of paclitaxel at 2m2 while other protocols dose paclitaxel according to actual body weight (ABW). In endometrial cancer where a significant portion of patients are obese this dosing difference may affect clinical outcome. We performed a retrospective review of patients with endometrial cancer who received paclitaxel and carboplatin after surgical staging. We compared patients who received paclitaxel dosed according to ABW with patients whose dose was capped at 2m2 to determine if differences in dosing affected progression free survival (PFS). Methods: Patients with endometrial cancer undergoing adjuvant treatment with paclitaxel and carboplatin from January 2000 to January 2008 were identified. Patient age, endometrial histology, stage, BSA, and paclitaxel treatment dose were collected and progression free survival was determined. Differences in outcome were compared and evaluated using student's t test. Results: 109 women were identified of whom 70 were treated according to their ABW (<2m2) and 39 obese patients received paclitaxel dose capped at 2m2. 95% of all the patients received the complete course of chemotherapy. PFS for both groups were 21.4±2.2 and 23.2±2.2 months with no significant difference in PFS (p = 0.62). When evaluating patients with endometrioid histology alone, no difference between patients receiving dosages according to ABW compared to those whose dosages were capped at 2m2 (25 patients vs. 19 patients, PFS 19.3±3.7 and 27.0±3.7 respectively, p = 0.16). However for patients with serous histology, PFS was significantly greater in those patients treated per their ABW when compared to patients capped at 2m2 (45 patients vs. 20 patients, PFS 30.2±3.2 and 19.6±3.5 months respectively, p = 0.05). Conclusions: There was no difference in PFS for patients with endometrioid cancer who were treated with ABW vs. capped doses of paclitaxel. However patients with serous histology experienced longer PFS when receiving paclitaxel dosed per ABW as compared to patients whose dose was capped at 2m2. This difference may reflect increased sensitivity of serous cancers to chemotherapy or other unknown biologic variables. Capping paclitaxel dosing in patients with serous endometrial cancers may affect their PFS. No significant financial relationships to disclose.