Novel Methods for Reporting of Exercise Dose and Adherence: An Exploratory Analysis

Abstract

Purpose: The purpose of this study was to explore whether methods adapted from oncology pharmacological trials have utility in reporting adherence (tolerability) of exercise treatment in cancer.

Methods: Using a retrospective analysis of a randomized trial, 25 prostate cancer patients received an aerobic training regimen of 72 supervised treadmill walking sessions delivered thrice weekly between 55% and 100% of exercise capacity for 24 consecutive weeks. Treatment adherence (tolerability) was assessed using conventional (lost to follow-up and attendance) and exploratory (e.g., permanent discontinuation, dose modification, and relative dose intensity) outcomes.

Results: The mean total cumulative "planned" and "completed" dose was 200.7 ± 47.6 and 153.8 ± 68.8 MET·h, respectively, equating to a mean relative dose intensity of 77% ± 24%. Two patients (8%) were lost to follow-up, and mean attendance was 79%. A total of 6 (24%) of 25 patients permanently discontinued aerobic training before week 24. Aerobic training was interrupted (missing ≥3 consecutive sessions) or dose reduced in a total of 11 (44%) and 24 (96%) patients, respectively; a total 185 (10%) of 1800 training sessions required dose reduction owing to both health-related (all nonserious) and non-health-related adverse events. Eighteen (72%) patients required at least one session to be terminated early; a total of 59 (3%) sessions required early termination.

Conclusions: Novel methods for the conduct and reporting of exercise treatment adherence and tolerability may provide important information beyond conventional metrics in patients with cancer.

Fig. 1. “Planned” Aerobic Training Prescription

Illustration of the planned, standardized aerobic training prescription template delivered to all patients allocated to the aerobic training group. The intensity and duration of each individual session (i.e., dose) as well as the sequencing of aerobic training dose across treatment weeks is presented. The intensity of each session was conducted at one of five different doses depicted by the colored bars as a percentage of VO_2peak: (1) black – 55%, (2) blue – 65%, (3) orange – 75%, (4) grey – 85%, and (5) red – 100%.. Black dots depict the planned duration of each session (mins), ranging from a minimum of 20 mins/session to a maximum of 60 mins/session including warm up and cool down. At the end of Week 12, the CPET was repeated to re-prescribe exercise intensity (green bar). The prescription template depicts the planned intensity, duration, and sequencing of sessions as per protocol without any dose modification or interruption.

Fig. 2. Ratio of “planned” to “completed” aerobic training dose

(A) Mean METs/week, and (B) total cumulative dose. Data presented for the intention to treat population including patients lost to follow up. “Planned” dose is depicted in the blue colored bars with “completed” dose depicted in the red colored bars. The average METs was assigned to sessions in which intensity was reduced (e.g., 75% reduced to 65%, imputed as 70%), whereas missed sessions were assigned zero METs.

Fig. 3. (A) Aerobic training compliance per session

Proportion of patients attending (green), requiring dose reduction (red), and missing (blue) “planned” aerobic training sessions. Data presented for the intention to treat population including patients lost to follow up. (B) Relative dose intensity across aerobic training dose intensity. Green depicts the percentage of sessions completed as planned; red depicts the percentage of sessions that required a dose reduction, while blue depicts percentage of missed sessions. Data presented for the intention to treat population including patients lost to follow up.