Time toxicity in patients receiving brachytherapy and hormonal therapy for recurrent prostate cancer: a cohort study

Time toxicity-the time patients spend receiving treatment and associated care-is an increasingly recognised burden of cancer treatment. Literature has largely relied on calendar-day-based measurement, which may obscure meaningful variation in time burden. This study aimed to quantify time toxicity with greater granularity by measuring it in hours.

We conducted a retrospective cohort study of patients with recurrent prostate cancer enrolled in a clinical trial of concurrent high-dose-rate brachytherapy and hormonal therapy at a tertiary cancer centre in Canada. Electronic medical records were reviewed for 180 days following treatment initiation. Time toxicity was quantified as median days and median hours per month spent in care. Subgroup analyses were conducted by encounter type. Sensitivity analyses incorporated the estimated travel time. Type I error was 0.05.

46 patients were included. Patients had a median of 6 healthcare encounters: 3 in Month 1, with the remaining 3 distributed across the following 5 months. Early encounters were predominantly treatment-related, whereas later encounters were largely monitoring or follow-up appointments. The median time toxicity was 13.7 hours over 6 months following treatment initiation, with 10.9 hours occurring in Month 1 and minimal time in subsequent months. Planned, in-person encounters accounted for nearly all toxicity. Incorporating travel time more than doubled time toxicity in sensitivity analyses.

Time toxicity was front-loaded and driven primarily by planned, in-person care. Expressing time toxicity in hours provided clearer quantification of early time burden. More granular, patient-centred measurement of time toxicity should be prioritised in future cancer trials.