Objective The aim of this study was to evaluate recurrence patterns and survival outcomes for patients with early-stage non-endometrioid endometrial adenocarcinoma treated with adjuvant high-dose rate vaginal brachytherapy with a low-dose scheme.
Methods A retrospective review was performed of patients with International Federation of Gynecology and Obstetrics (FIGO) stage I–II non-endometrioid endometrial cancer who received adjuvant vaginal brachytherapy with a low-dose regimen of 24 Gy in six fractions from November 2005 to May 2017. All patients had >6 months of follow-up. Rates of recurrence-free survival, overall survival, vaginal, pelvic, and distant recurrence were calculated by the Kaplan–Meier method. Prognostic factors for recurrence and survival were evaluated by Cox proportional hazards modeling.
Results A total of 106 patients were analyzed. Median follow-up was 49 months (range 9–119). Histologic subtypes were serous (47%, n=50), clear cell (10%, n=11), mixed (27%, n=29), and carcinosarcoma (15%, n=16). Most patients (79%) had stage IA disease, 94% had surgical nodal assessment, and 13% had lymphovascular invasion. Adjuvant chemotherapy was delivered to 75%. The 5-year recurrence-free and overall survival rates were 74% and 83%, respectively. By histology, 5-year recurrence-free/overall survival rates were: serous 73%/78%, clear cell 68%/88%, mixed 88%/100%, and carcinosarcoma 56%/60% (p=0.046 and p<0.01). On multivariate analysis, lymphovascular invasion was significantly associated with recurrence (HR 3.3, p<0.01). The 5-year vaginal, pelvic, and distant recurrence rates were 7%, 8%, and 21%, respectively. Vaginal and pelvic recurrence rates were highest for patients with carcinosarcoma, lymphovascular invasion and/or FIGO stage IB/II disease. At 5 years, vaginal and pelvic recurrence rates for patients with lymphovascular invasion were 33% and 40%, respectively. Patients with stage IA disease or no lymphovascular invasion had 5-year vaginal recurrence rates of 4% and pelvic recurrence rates of 6% and 3%, respectively.
Conclusions Adjuvant high-dose rate brachytherapy with a low-dose scheme is effective for most patients with early-stage non-endometrioid endometrial cancer, particularly stage IA disease and no lymphovascular invasion. Pelvic radiation therapy should be considered for those with carcinosarcoma, lymphovascular invasion and/or stage IB/II disease.
- endometrial neoplasms
- radiation oncology
- radiotherapy dosage
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Contributors AS, DB, GA, TC, and LL made substantial contributions to the conception or design of the work, as well as the acquisition, analysis or interpretation of data and drafting the manuscript. JP, BK, IB and MK made significant contributions to revising the work for critically for important intellectual content.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests LL is the principal investigator of an investigator-initiated clinical trial sponsored by AstraZeneca and has received non-financial support from AstraZeneca for sponsored travel and grant support from the Koch Institute at the Massachusetts Institute of Technology.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. Upon request, a data sharing agreement may be initiated with permission of the Dana-Farber Cancer Institute IRB.