Feasibility study: results of treatment of primary and recurrent adenocarcinoma of the corpus uteri with californium-252

Clinical evaluation of 252Cf neutron intracavitary therapy for primary endometrial adenocarcinoma

BACKGROUND

A pilot feasibility study of the neutron-emitting radioisotope 252Cf was done on patients with uterine adenocarcinoma and medically inoperable disease or unfavorable G3 histologic findings.

METHODS

252Cf intracavitary therapy was combined with 40-45 Gy of fractionated whole-pelvis photon therapy. In select patients, hysterectomy was performed.

RESULTS

Thirty-one patients with Stage I-III adenocarcinoma of the corpus uteri were treated with 252Cf neutron brachytherapy. The patients treated often were in poor general medical condition and had multiple chronic medical illnesses for which conventional radiation and surgery usually would not be recommended. 252Cf allowed short implant treatment time (hours), was usable in a small number of insertions (the average number of insertions was two), and was useful for treating large volume tumors. Stage and grade of the tumor were important determinants of patient survival. The 5-year actuarial survival was 83% for patients with Stage I disease but only 37% for those with Stage II disease (primarily adenosquamous cell carcinomas). The 5-year survival was 100% for patients with Grade 1 tumors, 88% for those with Grade 2 tumors, and 21% for those with Grade 3 tumors.

CONCLUSION

252Cf neutron brachytherapy was found to be an effective and well-tolerated therapy for endometrial carcinoma. The excellent therapeutic efficacy and good patient tolerance make it suitable for additional evaluation in future Phase II-III trials.

Stage I endometrial carcinoma: treatment of nonoperable patients with intracavitary radiation therapy alone

From 1976 to 1981, 171 patients with stage I endometrial adenocarcinoma (FIGO, 1971) underwent intracavitary radiotherapy alone because of medical contraindications to surgery and external-beam irradiation. The mean age of patients was 71 years, with the majority of patients being in the age group of 70-79 years. The intracavitary therapy consisted of intrauterine insertions of radium implants in three consecutive courses according to the packing method of Heyman. The estimated dose delivered to point A and to point B was 80 and 20 Gy (3500-7000 mg-hr; mean, 5500 mg-hr), respectively. The corrected 5-year survival rate for stage Ia was 76% and for stage Ib 72%. Grade had a profound effect on survival; corrected 5-year survival for G1 was 77%, for G2 68%, and for G3 53%, respectively. The total failure rate was 24% (40/171). Most of the recurrences occurred in the pelvis (35/171): uterus, 22; vagina, 9; rectum, 2; and bladder, 1. One patient had both vaginal and uterine failure and five had distant metastases (four abdominal and one pulmonary). No difference was seen in the failure rates of stage Ia and stage Ib patients. No major complications (necessitating hospital care or delay of treatment) were seen. Our findings suggest that for patients with stage I endometrial cancer who are unfit for surgery, intracavitary low-dose-rate radiation therapy alone is an effective alternative treatment with a low risk of complications.