Tailoring the Field and Indication of Adjuvant Pelvic Radiation for Patients with FIGO Stage Ib Lymph Nodes-Negative Cervical Carcinoma Following Radical Surgery Based on the GOG Score – A Pilot Study

Abstract

Introduction: The traditional indications for adjuvant pelvic radiotherapy (RT) for International Federation of Obstetrics and Gynecology (FIGO) stage Ib1 lymph nodes-negative cervix carcinoma following radical surgery based on histopathological factors, such as deep stromal invasion and lymphovascular space invasion (LVSI), were often inconsistently applied. The perceived risk of relapse was subjectively determined. This pilot study attempts to determine if the treatment outcome will be affected when the indication for RT is based on the Gynecologic Oncology Group (GOG) Risk Score (RS) and the field of adjuvant RT is tailored to the RS. Materials and Methods: From 1997 to 1999, 55 patients with FIGO stage Ib1 lymph nodes-negative cervical carcinoma limited to the cervix were prescribed RT following radical surgery, based on their RS, as follows: RS <40, RT is omitted; RS >40 to <120, modified (smaller) field RT; and RS >120, standard field pelvic RT. Their incidence and site of recurrence were compared with a similar cohort of 40 patients who were treated prior to 1997. Results: Prior to 1997, of the 40 patients, 10 patients were given standard field RT. There were 2 (5%) recurrent diseases. The mean duration of follow-up was 61.6 months (range, 1 to 103 months). The RS of 23 of the 30 patients who were not given RT were available. The mean RS was 22 with 5 patients having a score of >40. From 1997 onwards, of the 55 patients, 28 (51%) did not require RT, 13 (23%) were treated with modified (smaller) field RT and 14 (26%) were given standard field RT. There were 2 (3.6%) cases of relapse. The mean duration of follow-up was 36.4 months (range, 5 to 60 months). All patients with a RS of <40 did not suffer any relapse. Their survival outcomes were better when compared to patients who did not have any RT in the GOG Study. Conclusions: The results of this study indicated that postoperative adjuvant RT given to patients with a high GOG RS of >120, significantly improved their 5-year recurrence rate and disease-free survival, as compared with the similar group of patients who were without adjuvant therapy in the GOG study. Patients with a GOG risk-score of <40 may be safely spared from adjuvant pelvic RT. The current treatment protocol did not compromise the outcome in patients, compared with the use of a less precise treatment protocol in the past.