Does the progression-free interval after primary chemotherapy predict survival after salvage chemotherapy in advanced and recurrent endometrial cancer? A gynecologic oncology group ancillary data analysis

Background: This study evaluated whether progression-free interval (PFI) following primary chemotherapy (PCT) was predictive of overall survival (OS) after second-line chemotherapy in advanced/recurrent endometrial cancer (EC). Methods: This is a pooled analysis of patients who recurred after PCT and were treated with second-line chemotherapy on Gynecologic Oncology Group trials. PFI-1 measured from initiation of PCT to recurrence or treatment-free interval (TFI) measured from completion of PCT to initiation of second-line chemotherapy was evaluated in relation to clinical outcomes. Results: A total of 586 patients treated on 5 phase 3 PCT protocols were included. Baseline factors in primary setting associated with clinical outcome after PCT were also predictive of OS after second-line chemotherapy, including race, Gynecologic Oncology Group performance status, grade, and prior radiation therapy (P <.01). PFI-1 was the most significant factor predictive of survival after second-line chemotherapy, with a 30% reduction in the risk of death for PFI-1 >6 months compared with ≤6 months (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.59-0.84 [P <.0001]) and median OS after second-line chemotherapy of 10 versus 5 months. A total of 275 patients treated on 9 phase 2 second-line chemotherapy protocols were also evaluated, and TFI >3 months was associated with a 25% reduction in the risk of death (HR, 0.75; 95% CI, 0.57-0.97 [P =.030]) and median OS after second-line chemotherapy of 10 versus 7 months compared with TFI a;circ3 months. The tumor response to second-line chemotherapy was 9.6% versus 5.8%; the difference was not statistically significant. Conclusions: Time to recurrence after PCT is predictive of survival after recurrence in advanced/recurrent EC. However, there is no evidence that this variable can be used in selecting salvage chemotherapy. Cancer 2010. © 2010 American Cancer Society. Time to recurrence after primary chemotherapy is predictive of survival after recurrence in advanced endometrial cancer. However, there is no evidence that this variable provides significant prognostic information or can be used in selecting salvage chemotherapy.