Impact of Non-Adherence to Radiotherapy on 1-Year Survival in Cancer Patients in Catalonia, Spain.

Background: This study aims to assess the effects of non-adherence to external beam radiation therapy in cancer patients receiving treatment with a curative. Methods: This retrospective cohort study collected health records data for all cancer patients treated with external beam radiotherapy with curative intent in 2016 in Catalonia, Spain. Adherence was defined as having received at least 90% of the total dose prescribed. A logistic regression model was used to assess factors related to non-adherence, and its association with one-year survival was evaluated using Cox regression. Results: The final sample included 8721 patients (mean age 63.6 years): breast cancer was the most com-mon tumour site (38.1%), followed by prostate and colon/rectum. Treatment interruptions prolonged the total duration of therapy in 70.7% of the patients, and 1.0% were non-adherent. Non-adherence was associated with advanced age, female gender, and some localization of primary tumour (head and neck, urinary bladder, and haematological cancers). The risk of death in non-adherent patients was higher than in adherent patients (hazard ratio [HR] 1.63, 95% confidence interval 0.97-2.74), after adjusting for the potential confounding effect of age, gender, tumour site and comorbidity. Conclusion: Non-adherence to radiotherapy, as measured by the received dose, is very low in our setting, and it may have an impact on one-year survival. (C) 2020 The Authors. Published by Elsevier B.V.