Guideline-concordant treatment and clinical outcomes in older patients with endometrial cancer in Japan: a retrospective single-institution study

BACKGROUND: To evaluate achievement of Japanese guideline-concordant treatment (J-GCT) and examine its association with clinical outcomes among older patients with endometrial cancer. METHODS: We retrospectively reviewed 130 patients aged ≥ 70 years diagnosed between 2010 and 2019. J-GCT was defined as receipt of primary surgery, standard surgical staging including lymph node assessment when indicated, and risk-adapted adjuvant chemotherapy. Progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier methods and log-rank tests. Multivariable Cox models evaluated factors associated with PFS. RESULTS: J-GCT achievement was significantly lower in patients aged ≥ 75 years than in those aged 70-74 years (28.1% vs. 71.2%, P < 0.001). Patients aged ≥ 75 years less frequently underwent primary surgery (84.2% vs 97.3%, P = 0.011) and lymph node assessment (45.8% vs 80.3%, P < 0.001). Adjuvant chemotherapy for intermediate- or high-risk disease was less frequently administered in patients aged ≥ 75 years (38.7% vs 86.4%, P < 0.001). Perioperative complications were infrequent, and no treatment-related deaths were observed. J-GCT achievement was associated with improved PFS (P < 0.001) and OS (P = 0.004). In multivariable analysis adjusting for age and selected clinicopathologic factors, failure to achieve J-GCT remained associated with inferior PFS (adjusted hazard ratio 3.20, 95% confidence interval 1.43-7.15; P = 0.005). CONCLUSION: J-GCT achievement was lower among patients aged ≥ 75 years, particularly with respect to lymph node assessment and risk-adapted adjuvant chemotherapy. Failure to achieve J-GCT was associated with inferior PFS after adjustment, although this group included heterogeneous treatment patterns with potentially different prognostic implications. These findings support treatment decision-making based on structured clinical evaluation rather than chronological age alone.