Objectives: The appropriate sequencing of chemotherapy and radiation for the treatment of advanced endometrial cancer has not yet been determined. We sought to evaluate the outcome and adverse effects in patients with advanced stage endometrial cancer treated with postoperative chemotherapy and radiation to determine whether there was an advantage to a particular sequencing modality.
Methods: A multicenter retrospective analysis of patients with surgical stages III and IV endometrial cancer from 1993 to 2007 was conducted. Inclusion criteria were comprehensive staging procedure including hysterectomy, bilateral salpingo-oophorectomy, +/- selective pelvic/aortic lymphadenectomy, and treatment with adjuvant chemotherapy and radiation. Differences in frequencies of adverse events were tested with Pearson's chi-square test for comparing proportions. OS and PFS rates were calculated using Kaplan-Meier estimates. Hazard Ratios (HR) were estimated from multivariate Cox proportional hazards models.
Results: One hundred and nine patients with advanced stage endometrial cancer were identified who received postoperative adjuvant therapies; 41% (n=45) chemotherapy followed by radiation and then further chemotherapy (CRC), 17% (n=18) radiation followed by chemotherapy (RC), and 42% (n=46) chemotherapy followed by radiation (CR). The median age was 62 years (range: 35-83); 48% had endometrioid tumors; and 90% underwent optimal cytoreduction. There was no difference in the frequency of adverse effects due to either chemotherapy (p=0.35) or radiotherapy (p=0.14); dose modifications (p=0.055); or delays (p=0.80) between the various sequencing modalities. There was a significant difference between adjuvant treatment groups for both OS (log rank p=0.011) and PFS (log rank p=0.025), with those receiving CRC having a superior 3-year OS (88%) and PFS (69%) compared to RC (54% and 47%) or CR (57% and 52%). After adjusting for stage, age, grade, race, histology and cytoreduction status the OS HR for therapy was 5.74 (95% CI, 1.96 to 16.77) for RC and 2.60 (95% CI, 1.01 to 6.71) for CR, compared to CRC, p=0.003. When the analysis was restricted to optimally cytoreduced patients, those who were treated with RC were at higher risk for disease progression [HR=3.53 (95% CI, 1.29 to 9.71)], p=0.024, and death [HR=7.24 (95% CI, 2.25 to 23.37)], p=0.001, than patients who received sequential CRC.
Conclusions: Sequential CRC was associated with improved survival in women with advanced stage disease compared to other sequencing modalities with a similar adverse effect profile. Future clinical trials are needed to prospectively evaluate appropriate sequencing and types of adjuvant chemotherapy and radiotherapy for the treatment of advanced stage endometrial cancer.