Dropout from exercise trials among cancer survivors-An individual patient data meta-analysis from the POLARIS study.

INTRODUCTION: The number of randomized controlled trials (RCTs) investigating the effects of exercise among cancer survivors has increased in recent years; however, participants dropping out of the trials are rarely described. The objective of the present study was to assess which combinations of participant and exercise program characteristics were associated with dropout from the exercise arms of RCTs among cancer survivors. METHODS: This study used data collected in the Predicting OptimaL cAncer RehabIlitation and Supportive care (POLARIS) study, an international database of RCTs investigating the effects of exercise among cancer survivors. Thirty-four exercise trials, with a total of 2467 patients without metastatic disease randomized to an exercise arm were included. Harmonized studies included a pre and a posttest, and participants were classified as dropouts when missing all assessments at the post-intervention test. Subgroups were identified with a conditional inference tree. RESULTS: Overall, 9.6% of the participants dropped out. Five subgroups were identified in the conditional inference tree based on four significant associations with dropout. Most dropout was observed for participants with BMI >28.4 kg/m2 , performing supervised resistance or unsupervised mixed exercise (19.8% dropout) or had low-medium education and performed aerobic or supervised mixed exercise (13.5%). The lowest dropout was found for participants with BMI >28.4 kg/m2 and high education performing aerobic or supervised mixed exercise (5.1%), and participants with BMI ≤28.4 kg/m2 exercising during (5.2%) or post (9.5%) treatment. CONCLUSIONS: There are several systematic differences between cancer survivors completing and dropping out from exercise trials, possibly affecting the external validity of exercise effects.

Exercise-Intensity Adherence During Aerobic Training and Cardiovascular Response During Resistance Training in Cancer Survivors.

ABSTRACT: Quevedo-Jerez, K, Gil-Rey, E, Maldonado-Martín, S, and Herrero-Román, F. Exercise-intensity adherence during aerobic training and cardiovascular response during resistance training in cancer survivors. J Strength Cond Res 35(8): 2338-2345, 2021-Combined aerobic-resistance training has shown the best benefits has proved beneficial for cancer survivors (CS). To understand the adherence to the aerobic training program (in terms of the intensity and duration of the sessions) and the cardiovascular response to the resistance training program, heart rate (HR) of 48 CS was monitored in each training session with an HR monitor for a 2-year period. During aerobic training, CS had to maintain the intensity in zone 2 (Z2) (between the ventilatory threshold and respiratory compensation point). The time spent below Z2 (Z1), in Z2, and above Z2 (Z3) was assessed in both aerobic and resistance training. The exercise-intensity distribution (aerobic vs. resistance training) was as follows: Z1 6.6 ± 12.8% vs. 34.3 ± 29.9% (p < 0.001); Z2 66.6 ± 29.3% vs. 54.5 ± 27.6% (p < 0.05); and Z3 26.9 ± 29.9% vs. 11.2 ± 20.6% (p < 0.001). The most deconditioned CS (<4.5 metabolic equivalents [METs]) presented the poorest adherence in Z2 and spent the most time in Z3. A significant positive moderate-high correlation was found for the percentage of time in Z3 between resistance and aerobic exercise (r = 0.75, p < 0.001). In conclusion, the individualization of exercise intensity resulted in good adherence to the prescribed intensity. Less fit CS needed more supervision in their training sessions. Resistance training allowed the CS to train in moderate-vigorous intensities of cardiovascular response. Resistance training should have more scope in exercise prescriptions, particularly in deconditioned CS and in the first steps of exercise programs.

Effects and moderators of exercise on muscle strength, muscle function and aerobic fitness in patients with cancer: a meta-analysis of individual patient data.

OBJECTIVE: To optimally target exercise interventions for patients with cancer, it is important to identify which patients benefit from which interventions. DESIGN: We conducted an individual patient data meta-analysis to investigate demographic, clinical, intervention-related and exercise-related moderators of exercise intervention effects on physical fitness in patients with cancer. DATA SOURCES: We identified relevant studies via systematic searches in electronic databases (PubMed, Embase, PsycINFO and CINAHL). ELIGIBILITY CRITERIA: We analysed data from 28 randomised controlled trials investigating the effects of exercise on upper body muscle strength (UBMS) and lower body muscle strength (LBMS), lower body muscle function (LBMF) and aerobic fitness in adult patients with cancer. RESULTS: Exercise significantly improved UBMS (ß=0.20, 95% Confidence Interval (CI) 0.14 to 0.26), LBMS (ß=0.29, 95% CI 0.23 to 0.35), LBMF (ß=0.16, 95% CI 0.08 to 0.24) and aerobic fitness (ß=0.28, 95% CI 0.23 to 0.34), with larger effects for supervised interventions. Exercise effects on UBMS were larger during treatment, when supervised interventions included ≥3 sessions per week, when resistance exercises were included and when session duration was >60 min. Exercise effects on LBMS were larger for patients who were living alone, for supervised interventions including resistance exercise and when session duration was >60 min. Exercise effects on aerobic fitness were larger for younger patients and when supervised interventions included aerobic exercise. CONCLUSION: Exercise interventions during and following cancer treatment had small effects on UBMS, LBMS, LBMF and aerobic fitness. Demographic, intervention-related and exercise-related characteristics including age, marital status, intervention timing, delivery mode and frequency and type and time of exercise sessions moderated the exercise effect on UBMS, LBMS and aerobic fitness.

Targeting Exercise Interventions to Patients With Cancer in Need: An Individual Patient Data Meta-Analysis.

Background: Exercise effects in cancer patients often appear modest, possibly because interventions rarely target patients most in need. This study investigated the moderator effects of baseline values on the exercise outcomes of fatigue, aerobic fitness, muscle strength, quality of life (QoL), and self-reported physical function (PF) in cancer patients during and post-treatment. Methods: Individual patient data from 34 randomized exercise trials (n = 4519) were pooled. Linear mixed-effect models were used to study moderator effects of baseline values on exercise intervention outcomes and to determine whether these moderator effects differed by intervention timing (during vs post-treatment). All statistical tests were two-sided. Results: Moderator effects of baseline fatigue and PF were consistent across intervention timing, with greater effects in patients with worse fatigue (Pinteraction = .05) and worse PF (Pinteraction = .003). Moderator effects of baseline aerobic fitness, muscle strength, and QoL differed by intervention timing. During treatment, effects on aerobic fitness were greater for patients with better baseline aerobic fitness (Pinteraction = .002). Post-treatment, effects on upper (Pinteraction < .001) and lower (Pinteraction = .01) body muscle strength and QoL (Pinteraction < .001) were greater in patients with worse baseline values. Conclusion: Although exercise should be encouraged for most cancer patients during and post-treatments, targeting specific subgroups may be especially beneficial and cost effective. For fatigue and PF, interventions during and post-treatment should target patients with high fatigue and low PF. During treatment, patients experience benefit for muscle strength and QoL regardless of baseline values; however, only patients with low baseline values benefit post-treatment. For aerobic fitness, patients with low baseline values do not appear to benefit from exercise during treatment.