Clinical Outcomes of Image Guided Adaptive Hypofractionated Weekly Radiation Therapy for Bladder Cancer in Patients Unsuitable for Radical Treatment

Abstract

Purpose and objectives: We report on the clinical outcomes of a phase 2 study assessing image guided hypofractionated weekly radiation therapy in bladder cancer patients unsuitable for radical treatment.

Methods and materials: Fifty-five patients with T2-T4aNx-2M0-1 bladder cancer not suitable for cystectomy or daily radiation therapy treatment were recruited. A "plan of the day" radiation therapy approach was used, treating the whole (empty) bladder to 36 Gy in 6 weekly fractions. Acute toxicity was assessed weekly during radiation therapy, at 6 and 12 weeks using the Common Terminology Criteria for Adverse Events version 3.0. Late toxicity was assessed at 6 months and 12 months using Radiation Therapy Oncology Group grading. Cystoscopy was used to assess local control at 3 months. Cumulative incidence function was used to determine local progression at 1 at 2 years. Death without local progression was treated as a competing risk. Overall survival was estimated using the Kaplan-Meier method.

Results: Median age was 86 years (range, 68-97 years). Eighty-seven percent of patients completed their prescribed course of radiation therapy. Genitourinary and gastrointestinal grade 3 acute toxicity was seen in 18% (10/55) and 4% (2/55) of patients, respectively. No grade 4 genitourinary or gastrointestinal toxicity was seen. Grade ≥3 late toxicity (any) at 6 and 12 months was seen in 6.5% (2/31) and 4.3% (1/23) of patients, respectively. Local control after radiation therapy was 92% of assessed patients (60% total population). Cumulative incidence of local progression at 1 year and 2 years for all patients was 7% (95% confidence interval [CI] 2%-17%) and 17% (95% CI 8%-29%), respectively. Overall survival at 1 year was 63% (95% CI 48%-74%).

Conclusion: Hypofractionated radiation therapy delivered weekly with a plan of the day approach offers good local control with acceptable toxicity in a patient population not suitable for radical bladder treatment.

Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Figures

Fig. 1

Worst symptoms or acute toxicity as graded by the Common Terminology Criteria for Adverse Events CTCAE version 3.0. Total number of patients available for assessment at each time point experiencing any toxicity: before radiation therapy (RT), 55; RT week 1, 54; week 2, 53; week 4, 49; week 5, 49; week 6, 45; 6 weeks after RT, 41; 12 weeks after RT, 23. Abbreviations: GI = gastrointestinal; GU = genitourinary.

Fig. 2

Worst late toxicity at 6 and 12 months as graded by Radiation Therapy Oncology Group (RTOG). Total number of patients available for assessment at each time point experiencing late toxicity: 6 months, 31; 12 months, 23.

Fig. 3

Cumulative incidence of local progression using death resulting from other causes as competing risk, for all patients and stratified by stage. Abbreviation: CI = confidence interval.

Fig. 4

Kaplan-Meier plots for rates of overall survival and stratified by stage. Abbreviation: CI = confidence interval.