Benefit of external irradiation in pathologic stage I endometrial carcinoma: a prospective clinical trial of 605 patients who received postoperative vaginal irradiation and additional pelvic irradiation in the presence of unfavorable prognostic factors.

Six hundred and five cases of endometrial carcinoma, pathologic stage I, without definable extrauterine disease were initially treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy, followed by high-dose-rate iridium-192 irradiation of the vagina. External irradiation of the pelvis was performed only for patients with poor prognostic factors. Five-year survival was calculated by the product-limit method of Kaplan and Meier. Three hundred and forty-eight patients with tumor invasion of the inner third, of any tumor grade, received postoperative vaginal irradiation only. Twenty-eight patients with grade 1 tumor invasion of the middle third received vaginal irradiation only. One hundred and six patients with grade 2 or 3 tumor and infiltration of the middle third received vaginal and external irradiation of the pelvis. One hundred and twenty-three patients with deep muscle invasion of the external third of the myometrium received vaginal and pelvic irradiation. Differences in survival figures were not significant. Survival of the treatment group with good prognosis who received vaginal irradiation alone (91%) was similar to that of the group with poor prognosis who received additional pelvic irradiation (87.7%). Despite the unfavorable situation of patients with poor prognostic factors, treatment results after additional external irradiation were relatively equal to the results for patients with good prognostic factors who had not received external irradiation. Therefore, the benefit of external irradiation in patients with stage I endometrial carcinoma with unfavorable prognostic factors seems evident.