ESTRO 2021 Abstract Book

S110

ESTRO 2021

of Cancer Research, London, United Kingdom; 4 Institute of Cancer Research, Clinical Trials and Statistics Unit, London, United Kingdom

Purpose or Objective To establish whether patient gender has an impact on the long-term quality of life and toxicity scores of patients treated for bladder cancer within the BC2001 (chemo)radiotherapy trial. Materials and Methods BC2001 randomised patients to radiotherapy with or without chemotherapy and/or to standard versus reduced high-dose volume radiotherapy. Quality of life data was collected using the Functional assessment of Cancer Therapy bladder cancer (FACT-BL) questionnaire. Toxicity data was assessed by clinicians using RTOG (Radiation Therapy Oncology Group). Data was collected at baseline, post-treatment, at 6- and 12-months post randomisation and then annually to 5 years. Changes from baseline in bladder-specific sub-scale (BLCS), TOTAL and TOI scores of the FACT-BL at years 1, 3 and 5 after radiotherapy were key endpoints of interest. A linear regression model (ANCOVA) was used to estimate gender differences in QoL score change from baseline, adjusting by baseline score. Treatment group and any baseline features that were associated with QoL score change in univariate models (at a significance level of 0.05) were included in the adjusted model. Individual items in the FACT-BL and toxicity endpoints at 1, 3- and 5-years were cross-tabulated with gender groups, and appropriate chi-square tests used to compare them. Results 452 patients were enrolled in the QoL sub study of which 367 were male and 85 were female. There were no significant differences in baseline characteristics including treatment group between the two genders. There was no significant difference between genders in the change from baseline TOTAL or TOI score at any point. Within the BLCS score the mean difference in baseline to score at year 3 was 0.24 in males and -5.18 in females, giving a mean difference of 5.42 (95% CI 2.79-8.05) (p=0.002). Mean BLCS score by gender over timeis shown in Figure1. Proportion of patients with clinically significant (3-point) changes in BCLS are shown in Figure 2. On review of individual components of the BLCS sub score at year 3, females had a significantly worse scores on the components “I have trouble controlling my urine” (20% of females having no toxicity compared to 54% of males) and “It burns when I urinate” (8% of females compared to 1% of males having grade 3 or 4 toxicity). 27% of female patients reported an RTOG Grade 3 or 4 toxicity compared to 16% of male patients at any point of follow up (p=0.027), with an increase in GI toxicity in females. At year 1, 13% of females reported grade 3 or 4 toxicity compared to 2% of males (p=0.002). This gradually improved with 8% of females reporting a grade 3 or 4 toxicity at year 3 and both sexes reporting a 3% level of grade 3 or 4 toxicity at year 5 in line with 2% at baseline.