Adjuvant radiotherapy in incompletely staged IC and II endometrioid uterine cancer.

OBJECTIVES: To estimate if adjuvant radiotherapy improves the disease-specific survival of patients with clinical stage IC and II endometrioid corpus cancer who did not undergo lymphadenectomy.

METHODS: Information was obtained on patients with endometrioid corpus cancer from the National Cancer Institute database between 1988 and 2001. Data were analyzed using Kaplan-Meier and Cox proportional hazards regression methods.

RESULTS: A total of 3,664 patients (median age 70 years) with clinical stage IC to II endometrioid carcinoma did not undergo lymphadenectomy, of which 2,170 had stage IC and 1,494 stage II disease. Of these, 1,175 had grade 1, 1,637 had grade 2, 693 had grade 3, and in 159, grade was unknown. The 5-year disease-specific survival rates of clinical stage IC compared with stage II patients were 91.3% and 86.7% (P<.001). Of the 1,964 who received adjuvant radiotherapy, the 5-year disease-specific survival rate was 89.9% compared with 87.8% in those who did not undergo further treatment (P=.04). Adjuvant radiation improved the disease-specific survival rate of those with stage II disease, (86.5% compared with 81.9%; P=.02), but not in those with stage IC disease (91.7% compared with 92.6%; P=.68). The benefit of radiotherapy was significant in patients with grade 3 disease and patients 70 years or older (88.2% compared with 83.3%; P<.001). On multivariable analysis, age, stage, and grade were significant independent prognostic factors for disease-specific survival.

CONCLUSION: Adjuvant radiotherapy marginally improved the survival of clinically staged IC-II endometrioid uterine cancer patients without lymphadenectomy. After excluding those without hysterectomy, radiotherapy did not significantly affect disease-specific survival.

LEVEL OF EVIDENCE: II.