Adjuvant Radiotherapy in the Oldest-Old: A National Spanish Multicenter Analysis of Endometrial Cancer Patients Aged ≥ 80 Years

Objectives: The incidence of endometrial cancer is rising among elderly women due to population aging. However, patients aged ≥ 80 years remain underrepresented in clinical trials, and their management is often influenced by age rather than clinical suitability. This multicenter retrospective study aimed to evaluate treatment patterns, oncologic outcomes, prognostic factors, and the safety of adjuvant radiotherapy (RT) in Spanish women aged ≥ 80 years with surgically treated endometrial cancer. Methods: We analyzed data from 353 patients aged ≥ 80 years treated with curative-intent surgery between 2003 and 2019 across 11 centers. Adjuvant RT included external beam radiotherapy (EBRT), vaginal brachytherapy (VB), or both. Toxicity was graded using CTCAE v5.0. Survival outcomes were assessed using Kaplan–Meier and Cox regression analyses. Results: The median age was 83 years; 83.5% had early-stage disease. Adjuvant RT was administered to 227 patients (64.3%), and chemotherapy to only 13. Grade ≥ 3 toxicity was rare (<1%). Five-year outcomes were as follows: local control (88.9%), cancer-specific survival (68.7%), and overall survival (58.7%). In multivariable analysis, VB alone and combined EBRT + VB were independently associated with improved local control. No RT modality was independently associated with overall survival, although favorable trends were observed for VB alone and EBRT + VB. Higher comorbidity burden (CCI ≥ 5), but not age ≥ 85 years, was independently associated with worse overall survival. Conclusions: Adjuvant RT was associated with favorable oncologic outcomes and a low incidence of severe toxicity in women aged ≥ 80 years with endometrial cancer. These findings support individualized treatment based on tumor characteristics and comorbidity rather than chronological age alone. A multidisciplinary approach incorporating geriatric assessment may further support personalized treatment decision-making in this growing patient population.