Objectives To elucidate unmet needs in high-risk endometrial cancer (EC), this study described perioperative treatment patterns in Medicare beneficiaries with high-risk EC and quantified the impact of disease recurrence on clinical and economic outcomes among patients receiving adjuvant therapy. Methods Patients aged ≥66 years with high-risk EC (stage I/II EC of non-endometrioid histology or stage III/IVA EC of any histology) receiving hysterectomy with bilateral salpingo-oophorectomy from SEER-Medicare data (2007–2019) were identified; perioperative treatment patterns were described. Post-operative treatment patterns were described among patients receiving adjuvant therapy; overall survival (OS), all-cause and EC-related healthcare resource utilization and costs were evaluated from recurrence date (using a claims-based algorithm developed with clinical input) for recurrent patients and from a frequency-matched date for non-recurrent patients. Results Of 2,279 patients receiving EC surgery, 3.1% received neoadjuvant therapy and 55.3% received adjuvant therapy. Among 1,199 patients receiving adjuvant therapy, systemic adjuvant therapy with radiation (38.9%) was most common. Median OS was 1.4 years among 378 (31.5%) recurrent patients identified over a median follow-up of 3.7 years. Recurrent patients had significantly higher per-patient-year rates of all-cause outpatient visits (37.7 vs. 22.6), EC-related outpatient visits (14.5 vs. 3.0), and all-cause hospitalizations (1.3 vs. 0.4) than non-recurrent patients, and an excess of $84,562 and $62,128 in all-cause and EC-related annual costs, predominantly driven by hospitalizations. Conclusions Our findings highlight the considerable clinical and economic burden experienced by patients with high-risk EC experiencing recurrence and emphasize the unmet need for novel therapies in early settings to mitigate this burden.