POSTOPERATIVE RADIATION-THERAPY IN CLINICAL STAGE-I ENDOMETRIAL CANCER - CORPUS, CERVICAL, AND LOWER UTERINE SEGMENT INVOLVEMENT - PATTERNS OF FAILURE

PURPOSE: To evaluate involvement of the lower uterine segment (LUS) in adenocarcinoma of the endometrium and to identify patterns of treatment failure. MATERIALS AND METHODS: Two hundred four patients, aged 29-92 years, with endometrial carcinoma underwent surgery. Postoperative radiation therapy was administered for adverse histologic criteria, including deep myometrial invasion, high grade, or LUS involvement. RESULTS: The incidence of tumor involvement of the LUS was 19%; of the cervix, 14%; and of the corpus, 67%. Distant metastasis occurred in 3% of patients with LUS involvement and in 17% of patients with cervical involvement The local recurrence rate was 50% among patients with LUS involvement with no other risk factors and no postoperative radiation therapy and was 3% among those who underwent radiation therapy (P =.023). CONCLUSION: Early local-regional spread may be the primary mechanism of treatment failure in tumor invasion of the LUS. Aggressive local management, including postoperative radiation therapy, may be necessary.