Clinical outcomes following conventional external beam radiotherapy boost in Japanese patients with cervical cancer who are ineligible for intracavitary brachytherapy

Abstract

Objective: While external beam radiotherapy boost has been one of the standard management options for locally advanced cervical cancer that is not treatable with intracavitary brachytherapy, its efficacy remains unclear. We assessed clinical outcomes in Japanese patients with cervical cancer who underwent external beam radiotherapy alone and identified related prognostic factors.

Methods: Patients treated with definitive external beam radiotherapy for cervical cancer unsuitable for intracavitary brachytherapy, including whole pelvic irradiation and external beam radiotherapy boost, were retrospectively examined. The endpoints were progression-free survival, overall survival and adverse events. Additionally, various patient-, tumor- and treatment-specific factors were evaluated to identify significant predictors of progression-free survival.

Results: The study included 37 patients; 3 (8%), 5 (14%), 17 (46%) and 12 (32%) had clinical International Federation of Gynecology and Obstetrics (FIGO) stages I, II, III and IVA, respectively. A total radiation dose of 56-70.2 Gy was administered (84% of patients received 59.4-60.4 Gy). The median follow-up period after radiotherapy was 17 (range, 2-84) months. The progression-free survival rates at 1 and 2 years were 45 and 29%, respectively; the corresponding overall survival rates were 74 and 43%, respectively. On univariate and multivariate analyses of progression-free survival at 2 years, International Federation of Gynecology and Obstetrics stage IVA and a maximum primary tumor diameter >5 cm were associated with significantly worse outcomes (P = 0.026 and P = 0.027, respectively).

Conclusion: Approximately 70% of patients with cervical cancer treated with external beam radiotherapy boost instead of intracavitary brachytherapy experienced disease progression within 2 years. These results stress the necessity of devising alternative non-intracavitary brachytherapy treatment approaches, particularly for patients with International Federation of Gynecology and Obstetrics stage IVA and bulky primary tumors.

Keywords: EBRT monotherapy; brachytherapy ineligibility; cervical cancer; external beam radiotherapy boost.