Prognostic value of response to external radiation in stage IIIB cancer cervix in predicting clinical outcomes: A retrospective analysis of 556 patients from India

Abstract

Background and purpose To evaluate the prognostic significance of response to external beam radiation (EBRT) in predicting the clinical outcomes in stage IIIB cancer cervix and to find out factors affecting response to EBRT. Patients and methods This retrospective study included 556 patients of cancer cervix stage IIIB treated between 1996 and 2001 with EBRT (46 Gy/23fx/4.5 weeks) followed by intracavitary radiotherapy (ICRT). At the end of EBRT, response to EBRT was grouped as ‘no gross residual tumor’(NRT) or ‘gross residual tumor’(GRT). Results Follow up ranged from 2 to 93 months with a median of 36 months. Median dose to point A was 81 Gy. At the end of EBRT, 393 patients (70.7%) attained NRT response. NRT responders had significantly better 5 year pelvic control, disease free survival (DFS) and overall survival (OS) than those who had a GRT response (75.6 vs. 54.6%; 60.6 vs. 31.9% and 62.6 vs. 33.7%, respectively; all P values <0.0001). Apart from response to EBRT, overall treatment time also has emerged as an independent factor to affect all clinical outcomes in multivariate analysis but age had significant impact on pelvic control only. Age was the only factor, which significantly influenced the response to EBRT in univariate as well as multivariate analysis ( P=<0.001, OR=1.973, 95% C.I. 1.357–2.868). Patients with age more than 50 years had more NRT response (77%) than patients with age less than 50 years (63.8%). Conclusions Patients who attain NRT response to EBRT will have an impressive long term pelvic control, DFS and OS in stage IIIB cancer cervix. Older patients (≥50 years) attain significantly higher NRT rates than younger patients.