Multi-institutional analysis of vaginal brachytherapy without external beam radiation therapy for stage II endometrial cancer patients.
Harkenrider MM, Adams W, Nieto K, Aref I, Bergman DM, Chundury A, Elshaikh MA, Gaffney DKK, Jhingran A, Lee LJ, Paydar I, Ra K, Schwarz JK, Thorpe C, Viswanathan AN, and Small W. Multi-institutional analysis of vaginal brachytherapy without external beam radiation therapy for stage II endometrial cancer patients. Int J Radiat Oncol Biol Phys 2017; 99(2):S112.
Int J Radiat Oncol Biol Phys
Purpose/Objective(s): Vaginal brachytherapy (VBT) and external beam radiotherapy (EBRT) improve locoregional recurrence for Stage I endometrial cancer, and risk factors for recurrence have been previously described. Limited data exist for the use of VBT without EBRT for Stage II patients. The aim of this study is to perform a multi-institutional analysis of Stage II endometrial cancer patients treated with VBT alone without EBRT. Purpose/Objective(s): We analyzed patients with stage II endometrial cancer treated with VBT without EBRT at five institutions. All patients had cervical stromal invasion concordant with 2009 FIGO staging. Univariate and multivariable frailty survival models that allow for clustering of patients within their study site were performed to assess clinicopathologic risk factors for recurrence and death. Results: One hundred seven patients met inclusion criteria with median follow-up of 57.9 (95% CI: 51.5-70.4) months. Median age was 61 years (range 42-89 years). Endometrioid, serous (USC), clear cell (CCC), and carcinosarcoma (CS) histologies comprised 83.2%, 11.2%, 4.7%, and 0.9%, respectively. Lymphovascular invasion (LVI) was present in 36.2% of patients. Pelvic and para-aortic node dissections were performed in 87.8% and 54.2%, respectively. Chemotherapy was delivered in 28.2% of patients. Seventy-seven patients had endometrioid type treated with VBT only without chemotherapy. The crude rates of vaginal failure, non-vaginal pelvic failure, and distant metastasis were 2.6%, 3.9%, and 6.5%, respectively. Thirty patients had USC/CCC/CS histologies and/or were treated with chemotherapy. These patients had vaginal failure, non-vaginal pelvic failure, and distant metastasis of 0%, 10.0%, and 20.0%, respectively. For the entire cohort, the 3-year estimate of vaginal failure, non-vaginal pelvic failure, and distant metastasis was 2.2%, 7.2%, and 7.4%, respectively. On UVA for distant metastasis, grade 3 (compared to grade 1) trended toward hazardous with HR 5.59 (95% CI: 0.83-37.55, P =.08). Three-year survival for the entire cohort was 85.9%. On UVA for survival, USC histology was the greatest predictor of death with HR 2.78 (95% CI: 1.06-7.14, P =.03) compared to endometrioid type. There was no difference in survival between CCC and endometrioid type (P = 0.18). Presence of LVI trended toward increased risk of death with HR 2.16 (95% CI: 0.97-4.17, P = 0.06). On UVA and MVA, receipt of chemotherapy trended toward hazard for death (95% CI: 0.12-1.05, P = 0.06). Conclusion: This is the largest report of Stage II endometrial cancer patients treated with VBT without EBRT. Patients with Stage II endometrial cancer treated with VBT without EBRT, with favorable clinicopathologic features, have low rates of vaginal and pelvic failures. VBT without EBRT may be a reasonable adjuvant treatment option for appropriately selected patients. Patients with higher risk histologies, including those treated with chemotherapy, have a higher risk of pelvic and distant failure and require additional study for improved adjuvant therapy.