Pentoxifylline and vitamin E drug compliance after adjuvant breast radiation therapy

Abstract

Purpose: Breast fibrosis is a common late effect after therapeutic irradiation that can result in pain, poor cosmesis, and functional impairment. Randomized trials have demonstrated that radiation fibrosis may be preventable with a medication regimen of pentoxifylline and vitamin E. This study investigates patient compliance with pentoxifylline therapy while examining possible correlations to compliance. Methods and materials: We identified 90 patients who were prescribed pentoxifylline (400 mg 3 times daily) and vitamin E (400 IU once daily) after adjuvant breast radiation. A retrospective cohort study was conducted using medical record analysis. Data were collected, including patient age, comorbid conditions, concurrent medications, duration of pentoxifylline and vitamin E therapy, dose adjustments, patient-reported side effects, and cause for discontinuation. A multivariate analysis of the correlation between medication compliance and these categorical variables was assessed with a χ2 analysis of independence. Results: Patient compliance with pentoxifylline and vitamin E therapy was found to be poor in 33 of 87 patients (38%) in the cohort, necessitating either dose reductions or discontinuation of therapy. There was a statistically significant correlation between concurrent antiemetic therapy and successful completion of pentoxifylline regimen. Of those on antiemetic therapy, 89% completed pentoxifylline as prescribed versus 48% of those without antiemetics (P