Low-dose preoperative radiation therapy for adenocarcinoma of the endometrium. A pilot study.
A pilot study using low-dose preoperative radiation therapy, i.e., 10 Gy in 3 to 4 days as an adjuvant preoperative procedure for grade 2 or 3 (FIGO classification) endometrial carcinoma, was done. The concept of low-dose preoperative radiation therapy is to administer treatment, either surgical or radiotherapeutic, postoperatively according to the surgical and pathologic findings, allowing identification of those patients with previously undiagnosed extensive metastatic disease outside the pelvis found at laparotomy in whom routine pelvic radiation therapy is futile, as well as those patients with relatively low risk of recurrence who may not require further radiotherapy. Forty-four patients with clinical Stage I, grade 2 or 3 with adenocarcinoma of the endometrium were entered into the pilot study. Following surgery, 68% remained Stage I by pathologic examination, and in the remaining patients the stages were changed to II in seven, III in three, and IV in four. Postoperative treatment was administered according to extent of the disease found at surgery. The 4-year actuarial probability of survival rate for the entire group of patients with clinical Stage I disease was 80%; corresponding disease-free rate was 77%. For the Stage I disease confirmed by pathologic examination, the corresponding rate was 96%. The rates for Stages II through IV, as shown by pathologic findings at laparotomy, were 53% and 42%, respectively. In this pilot stud, a treatment policy for clinical Stage I, grade 2 or 3 adenocarcinoma of the endometrium using low-dose preoperative radiation therapy is recommended.