Dose-response effects of aerobic exercise on body composition among colon cancer survivors: a randomised controlled trial

Feasibility of two levels of protein intake in patients with colorectal cancer: findings from the Protein Recommendation to Increase Muscle (PRIMe) randomized controlled pilot trial

BACKGROUND

Low muscle mass (MM) predicts unfavorable outcomes in cancer. Protein intake supports muscle health, but oncologic recommendations are not well characterized. The objectives of this study were to evaluate the feasibility of dietary change to attain 1.0 or 2.0 g/kg/day protein diets, and the preliminary potential to halt MM loss and functional decline in patients starting chemotherapy for stage II-IV colorectal cancer.

PATIENTS AND METHODS

Patients were randomized to the diets and provided individualized counseling. Assessments at baseline, 6 weeks, and 12 weeks included weighed 3-day food records, appendicular lean soft tissue index (ALSTI) by dual-energy X-ray absorptiometry to estimate MM, and physical function by the Short Physical Performance Battery (SPPB) test.

RESULTS

Fifty patients (mean ± standard deviation: age, 57 ± 11 years; body mass index, 27.3 ± 5.6 kg/m2; and protein intake, 1.1 ± 0.4 g/kg/day) were included at baseline. At week 12, protein intake reached 1.6 g/kg/day in the 2.0 g/kg/day group and 1.2 g/kg/day in the 1.0 g/kg/day group (P = 0.012), resulting in a group difference of 0.4 g/kg/day rather than 1.0 g/kg/day. Over one-half (59%) of patients in the 2.0 g/kg/day group maintained or gained MM compared with 44% of patients in the 1.0 g/kg/day group (P = 0.523). Percent change in ALSTI did not differ between groups [2.0 g/kg/day group (mean ± standard deviation): 0.5% ± 4.6%; 1.0 g/kg/day group: -0.4% ± 6.1%; P = 0.619]. No differences in physical function were observed between groups. However, actual protein intake and SPPB were positively associated (β = 0.37; 95% confidence interval 0.08-0.67; P = 0.014).

CONCLUSION

Individualized nutrition counselling positively impacted protein intake. However, 2.0 g/kg/day was not attainable using our approach in this population, and group contamination occurred. Increased protein intake suggested positive effects on MM and physical function, highlighting the potential for nutrition to attenuate MM loss in patients with cancer. Nonetheless, muscle anabolism to any degree is clinically significant and beneficial to patients. Larger trials should explore the statistical significance and clinical relevance of protein interventions.

Effects of exercise or metformin on myokine concentrations in patients with breast and colorectal cancer: A phase II multi-centre factorial randomized trial

BACKGROUND

Physical activity and metformin pharmacotherapy are associated with improved clinical outcomes in breast and colorectal cancer survivors. Myokines are cytokines secreted from skeletal muscle that may mediate these associations.

METHODS

This hypothesis-generating analysis used biospecimens collected from a multi-centre 2 × 2 factorial randomized design of 116 patients with stage I-III breast and colorectal cancer who were randomized to 12 weeks of (1) aerobic exercise (moderate intensity titrated to 220 min/week); (2) metformin (850 mg daily for 2 weeks and then titrated to 850 mg twice per day); (3) aerobic exercise and metformin; or (4) control. Fourteen myokines were quantified using a multiplex panel. Myokine concentrations were log-transformed, and main effects analyses were conducted using linear mixed-effects regression models. The type I error rate was controlled with the Holm sequential testing procedure.

RESULTS

Randomization to exercise increased leukaemia inhibitory factor (1.26 pg/mL, 95% confidence interval [CI]: 0.69, 1.84; adjusted P = 0.001) and interleukin-15 (2.23 pg/mL, 95% CI: 0.87, 3.60; adjusted P = 0.013) compared with randomization to no exercise. Randomization to metformin decreased apelin (-2.69 pg/mL, 95% CI: -4.31, -1.07; adjusted P = 0.014) and interleukin-15 (-1.74 pg/mL, 95% CI: -2.79, -0.69; adjusted P = 0.013) compared with randomization to no metformin. Metformin decreased myostatin, irisin, oncostatin M, fibroblast growth factor 21 and osteocrin; however, these changes were not statistically significant after correction for multiple comparisons.

CONCLUSIONS

This pilot study demonstrates that randomization to exercise and metformin elicit unique effects on myokine concentrations in cancer patients. This hypothesis-generating observation warrants further basic, translational and clinical investigation and replication.

The effect of prehabilitation on long-term survival and hospital admissions in older patients undergoing elective colorectal cancer surgery

INTRODUCTION

There is a growing body of evidence for a beneficial effect of prehabilitation on short-term outcomes after colorectal cancer (CRC) surgery in older patients. However, long-term effects on survival or hospital admissions have not been investigated. This study reports these long-term outcomes from a previously published observational cohort study.

METHODS

We compared patients ≥75 years who received elective CRC surgery in Reinier de Graaf Hospital before (2010-2013: standard care) and after implementation of a multimodal prehabilitation program (2014-2015; prehabilitation). With a six-year follow-up period, we analyzed survival using the Kaplan-Meier method and the occurrence of one or more hospital admissions using logistic regression analyses.

RESULTS

Overall, 137 patients were included in the standard care group and 86 patients in the prehabilitation group. There were no differences in patients, tumor and treatment characteristics. After six years, 51.1% in the standard care group and 59.3% in the prehabilitation group (p = 0.167) were still alive. When corrected for confounders in the prehabilitation group less patients had one or more hospital admissions during follow-up (odds ratio (OR) 0.43 (95% CI 0.24-0.77).

CONCLUSIONS

Unfortunately these limited historical cohorts did not allow for strong conclusions concerning long-time survival. However, after prehabilitation less patients had hospital admissions during follow up. Hopefully, this first study into the long-term effects of multimodal prehabilitation will trigger more future research.

The dose-response effect of aerobic exercise on inflammation in colon cancer survivors

Background

Physical activity after surgical resection for colon cancer is associated with significantly longer disease-free survival. Inflammation is hypothesized to mediate the association between physical activity and disease-free survival in colon cancer.

Methods

In this exploratory analysis of a randomized dose-response trial, 39 colon cancer survivors who completed standard therapy were stratified by cancer stage and randomized in a 1:1:1 ratio to one of three treatment groups for 24 weeks of usual-care control, 150 min/wk of moderate-intensity aerobic exercise (low-dose), or 300 min/wk of moderate-intensity aerobic exercise (high-dose). Inflammation outcomes included high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL6), and soluble tumor necrosis factor-alpha receptor 2 (sTNFαR2). Mixed models for repeated measures were used to test the hypothesis that exercise was associated with dose-response reductions in inflammation; exploratory analyses examined treatment effects by cancer stage.

Results

In the overall population, aerobic exercise was not associated with dose-response reductions in hs-CRP, IL6, or sTNFαR2. Cancer stage modified the association between randomized group and hs-CRP (P=0.022) and IL6 (P<0.001) but not sTNFαR2 (P=0.39). In stage I-II disease, compared to control, exercise was not associated with inflammation outcomes. In stage III disease, compared to control, low-dose exercise reduced hs-CRP: -35.4% (95% CI: -70.1, -0.7) and IL6: -29.6% (95% CI: -58.4, -0.8) but not sTNFαR2: 2.7% (95% CI: sTNFαR2: -15.7, 21.1); high-dose exercise was not associated with inflammation outcomes in stage III disease.

Conclusion

This exploratory analysis offers preliminary data to support the hypothesis that inflammation may mediate the association between physical activity and disease-free survival in colon cancer.

Clinical trial registration

clinicaltrials.gov, identifier NCT02250053.

Bone health, body composition and physical fitness dose-response effects of 16 weeks of recreational team handball for inactive middle-to-older-aged males - A randomised controlled trial

In this study we aimed at analysing the effects of different weekly exercise volumes (1, 2 or 3 times 60-min) on bone health, body composition and physical fitness of inactive middle-to-older-aged males, after 16 weeks of recreational team handball (RTH). Fifty-four men (68 ± 4 years, stature 169 ± 6 cm; body mass 78.4 ± 10.7 kg; fat mass 27.1 ± 5.3%; BMI 27.4 ± 2.9 kg/m2; VO2peak 27.3 ± 4.8 mL/min/kg) were randomised into three intervention groups (TH1, n = 13; TH2, n = 15; or TH3, n = 12, performing 1, 2 and 3 weekly 60-min training sessions, respectively), and a control group (CG, n = 14). The training sessions consisted mainly of RTH matches played as small-sided and formal game formats (4v4, 5v5, 6v6 or 7v7) with adapted rules. Matches' mean and peak heart rate (HR) ranged from 78-80% and 86-89%HRmax, respectively, and distance covered from 4676 to 5202 m. A time x group interaction was observed for procollagen type-1 amino-terminal propeptide (P1NP), osteocalcin (OC), carboxy-terminal type-1 collagen crosslinks (CTX), sclerostin, upper and lower body dynamic strength, right arm fat mass, left and right arm, right leg and android total mass (TM; p ≤ 0.047) with the greatest effects being shown for TH2 and TH3 groups. Post-intervention group differences were observed in CTX, left arm and right leg TM (TH3 > TH1), P1NP (TH2 > CG), OC, right arm TM (TH3 > CG), upper (CG < TH1, TH2 and TH3) and lower body dynamic strength (CG < TH1 and TH3) (p ≤ 0.047). RTH was effective in enhancing bone health, body composition and physical fitness in middle-to-older-aged males, especially for the intervention groups that performed 2-3 weekly training sessions.ClinicalTrials.gov ID: NCT05295511.Trial registration: ClinicalTrials.gov identifier: NCT05295511.HighlightsAfter 16 weeks of recreational team handball small-sided and formal matches, inactive middle-to-older-aged males improved bone health, body composition and physical fitness, by performing 1, 2 or 3 60-min weekly sessions, however, greater improvements were shown in the groups that performed 2 or 3 weekly training sessions.Training intensity was similar across the intervention groups that performed recreational team handball for 1, 2 or 3 60-min weekly sessions, which means that training volume is most likely to be the reason for the different health effects shown.The very high fun levels reported by all intervention groups shows that recreational team handball is a social and fun exercise modality for middle-to-older-aged males, with potential to intrinsically motivate the participants and assure long-term adherence to exercise.

Longitudinal associations of sedentary behavior and physical activity with body composition in colorectal cancer survivors up to 2 years post treatment

PURPOSE

We investigated longitudinal associations of sedentary behavior, light-intensity physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) with body composition in colorectal cancer (CRC) survivors, between 6 weeks and 24 months post treatment. In addition, we explored whether body composition mediated associations of sedentary behavior and MVPA with fatigue.

METHODS

A prospective cohort study was conducted in 459 stage I-III CRC patients recruited at diagnosis. Measurements were performed of accelerometer-assessed sedentary time (hours/day), self-reported LPA and MVPA (hours/week), anthropometric assessment of body mass index (BMI), waist circumference and fat percentage (measures of adiposity), and muscle circumference and handgrip strength (measures of muscle mass/function) repeated at 6 weeks, and 6, 12 and 24 months post treatment. Longitudinal associations of sedentary time and physical activity with body composition were analyzed using confounder-adjusted linear mixed models. Mediation analyses were performed to explore the role of body mass index (BMI) and handgrip strength as mediators in associations of sedentary time and MVPA with fatigue.

RESULTS

Less sedentary time and LPA were, independent of MVPA, longitudinally associated with increased handgrip strength, but not with measures of adiposity. More MVPA was associated with increased adiposity and increased handgrip strength. Higher BMI partly mediated associations between higher sedentary time and more fatigue.

CONCLUSION

Within the first two years after CRC treatment, changes in sedentary behavior, physical activity and body composition are interrelated and associated with fatigue. Intervention studies are warranted to investigate causality.

TRIAL REGISTRATION

The EnCoRe study is registered at trialregister.nl as NL6904 (former ID: NTR7099).

Effects of exercise by type and duration on quality of life in patients with digestive system cancers: A systematic review and network meta-analysis

BACKGROUND

There is scant evidence regarding the effects of exercise type and duration on quality of life (QoL) in digestive system cancer (DSC) survivors. We aim to investigate the optimal type and duration of exercises to improve QoL for DSC survivors through a systematic review and network meta-analysis.

METHODS

A systematic literature search of PubMed, Embase, and Web of Science was performed. Eligibility for study inclusion was limited to studies that were randomized controlled trials involving all kinds of exercise in adult patients with DSCs, and the comparator was in standard care or other types of exercise. The primary outcome was QoL, including general health, physical health, mental health, and role function. Secondary outcomes included cancer-related symptoms such as fatigue, insomnia, depression, anxiety, and duration of hospital stay. The network meta-analyses were performed using a random-effect model.

RESULTS

The analysis included 32 eligible articles and a total of 2558 participants. Our primary outcome indicated that short-term aerobic exercise significantly enhanced general health (standardized mean differences (SMDs) = 0.66, 95% credible intervals (CrIs): 0.05 to 1.30, and also contributed to a better mental health (SMD = 0.37, 95%CrI: -0.06 to 0.81 and role function (SMD = 0.48, 95%CrI: -0.27 to 1.20). Although without significant changes, short-term resistance exercise tends to increase the physical health of patients with DSCs (SMD = 0.69, 95%CrI: -0.07 to 1.50) and effective in alleviating fatigue (SMD = -0.77, 95%CrI: -1.50 to 0.01). Short-term aerobic exercise was related to a lower score of insomnia (SMD = -1.20, 95%CrI: -2.40 to 0.06), depression (SMD = -0.51, 95%CrI: -1.50 to 0.45), and anxiety (SMD = -0.45, 95%CrI: -1.30 to 0.34). All types of exercise related to a trend of declined hospital stays (-0.87 to -5.00 days). Long-term resistance exercise, however, was negatively associated with general health (SMD = -0.33, 95%CrI: -1.70 to 1.00), physical health (SMD = -0.18, 95%CrI: -1.30 to 0.90), and role function (SMD = -1.20, 95%CrI: -2.50 to 0.11).

CONCLUSION

This study suggests that short-term aerobic exercise, with or without resistance exercise programs, enhances QoL (especially for general health) as well as relieves cancer-related symptoms for DSC survivors, while long-term resistance exercise may have negative effects, and thus should be adopted cautiously. These results provide important evidence for the management of DSCs.

Exercise and colorectal cancer: prevention and molecular mechanisms

Exercise and physical activity have been shown to be strongly associated with a decreased incidence rate of various chronic diseases especially numerous human malignancies. A huge number of clinical trials and meta-analysis have demonstrated that exercise is significantly effective in lowering the risk of colorectal cancer. In addition, it is suggested as an effective therapeutic modality against this cancer type. Therefore, in this review, we will review comprehensibly the effects of exercise in preventing, treating, and alleviating the adverse effects of conventional therapeutic options in colorectal cancer. Moreover, the possible mechanisms underlying the positive effects of exercise and physical activity in colorectal cancer, including regulation of inflammation, apoptosis, growth factor axis, immunity, epigenetic, etc. will be also discussed.

Exercise is an effective post-treatment management program in colorectal cancer survivals

Exercise improves muscle strength, cardiorespiratory fitness, emotional distress, physical activity, fatigue, and sleep quality in colorectal patients undergoing chemotherapy

Targeting and modulating insulin-like growth factor (IGF) system, inflammation, apoptosis, immunity, epigenetic, Leptin and Ghrelin, and signaling pathways are major underlying mechanisms for preventive effects of exercise in colorectal cancer

Obesity and Breast Cancer Risk: The Oncogenic Implications of Metabolic Dysregulation

CONTEXT

Breast cancer is increasing in prevalence in parallel with rising rates of obesity worldwide. Obesity is recognized as a leading modifiable risk factor for the development of breast cancer; however, this association varies considerably by clinicopathologic features, and the underlying mechanisms are complex.

EVIDENCE ACQUISITION

Pubmed literature search using combinations of "obesity," "breast cancer risk," "diet," "exercise," "weight gain," "weight loss," "adipose tissue inflammation," "crown-like structure," "immune markers," "metformin," "gliflozins," "SGLT-2i," "GLP1-RA," and related terms.

EVIDENCE SYNTHESIS

Elevated body mass index and weight gain are associated with increased risk of postmenopausal, hormone receptor-positive breast cancer. Emerging evidence suggests that adverse measures of body composition in individuals of any weight can also confer increased breast cancer risk. Mechanistically, various factors including altered adipokine balance, dysfunctional adipose tissue, dysregulated insulin signaling, and chronic inflammation contribute to tumorigenesis. Weight loss and more specifically fat mass loss through lifestyle and pharmacologic interventions improve serum metabolic and inflammatory markers, sex hormone levels, and measures of breast density, suggesting a link to decreased breast cancer risk.

CONCLUSION

Incorporating markers of metabolic health and body composition measures with body mass index can capture breast cancer risk more comprehensively. Further studies of interventions targeting body fat levels are needed to curb the growing prevalence of obesity-related cancer.

Association of Preoperative Physical Activity with Short- and Long-Term Outcomes in Patients Undergoing Palliative Resection for Metastatic Colorectal Cancer: An Inverse Probability of Treatment Weighting Analysis

Simple Summary

Physical activity is linked to the risk and the prognosis of colorectal cancer. However, the impact of preoperative physical activity on postoperative short-term and long-term outcomes is limited. The aim of our study was to elucidate the relationship of preoperative physical activity and postoperative outcomes in metastatic colorectal cancer patients who underwent palliative resection. After the inverse probability of the treatment weighting process, the metabolic equivalent of task < 12 group had a higher postoperative morbidity rate and mortality rate. No significant difference was found in overall survival. In patients undergoing palliative resection for metastatic colorectal cancer, preoperative leisure-time physical activity with the metabolic equivalent of task ≥ 12 was associated with reduced short-term postoperative morbidity and mortality; however, no difference was detected in long-term survival.

Abstract

A lack of physical activity is a generally accepted risk factor for colorectal cancer. However, research on the effect of preoperative physical activity on postoperative and long-term outcomes is limited, especially in patients with stage IV colorectal cancer who underwent palliative surgery. Patients who underwent bowel resection for stage IV primary colorectal cancer between January 1995 and December 2016 were retrospectively enrolled. A total of 2185 patients were divided into two groups according to preoperative leisure-time weekly physical activity as assessed by metabolic equivalent of task (MET) values: MET < 12 (n = 1845) and MET ≥ 12 (n = 340). Inverse probability of treatment weighting (IPTW) was used to reduce imbalance and selection biases between the two groups. After the IPTW process, the MET < 12 group showed a higher postoperative morbidity rate (18.7% vs. 10.6%; p < 0.001) and mortality rate (2.4% vs. 0.6%; p < 0.001) than the MET ≥ 12 group. No significant difference was found in overall survival. Weekly preoperative leisure-time physical activity with MET ≥ 12 was associated with reduced short-term postoperative morbidity and mortality in patients undergoing palliative resection for metastatic colorectal cancer. However, no difference was detected in long-term survival.

Exercise Cardio-Oncology: Exercise as a Potential Therapeutic Modality in the Management of Anthracycline-Induced Cardiotoxicity

Anthracyclines are one of the most effective chemotherapy agents and have revolutionized cancer therapy. However, anthracyclines can induce cardiac injuries through ‘multiple-hits', a series of cardiovascular insults coupled with lifestyle risk factors, which increase the risk of developing short- and long-term cardiac dysfunction and cardiovascular disease that potentially lead to premature mortality following cancer remission. Therefore, the management of anthracycline-induced cardiotoxicity is a serious unmet clinical need. Exercise therapy, as a non-pharmacological intervention, stimulates numerous biochemical and physiologic adaptations, including cardioprotective effects, through the cardiovascular system and cardiac muscles, where exercise has been proposed to be an effective clinical approach that can protect or reverse the cardiotoxicity from anthracyclines. Many preclinical and clinical trials demonstrate the potential impacts of exercise on cardiotoxicity; however, the underlying mechanisms as well as how to implement exercise in clinical settings to improve or protect against long-term cardiovascular disease outcomes are not clearly defined. In this review, we summarize the current evidence in the field of “exercise cardio-oncology” and emphasize the utilization of exercise to prevent and manage anthracycline-induced cardiotoxicities across high-risk and vulnerable populations diagnosed with cancer.

Protective effects of physical activity in colon cancer and underlying mechanisms: A review of epidemiological and biological evidence

Numerous epidemiological studies indicate that physical activity has a protective effect against colon cancer development and progression. Further, the relevant biological mechanisms where physical activity or exercise may improve survival have also been initially examined. In this review, we provide an overview of the epidemiological evidence to date which comprises 16 cohort studies of the effects of physical activity on colon cancer outcomes including cancer recurrence, cancer-specific and overall survival. Moreover, we present four potential mechanisms involving shear pressure, systemic milieu alteration, extracellular vesicles, and immune function by which physical activity and exercise may favorably impact colon cancer. Research currently in progress will provide definitive evidence of survival benefits resulting from exercise and future work will help clarify the role of targeted exercise and the relevant mechanisms involved.

The role of muscle depletion and visceral adiposity in HCC patients aged 65 and over undergoing TACE

Background

The incidence of hepatocellular carcinoma (HCC) has been increasing among the elderly populations. Trans-arterial chemoembolization (TACE), a widely used first-line non-curative therapy for HCCs is an issue in geriatrics. We investigated the prognosis of elderly HCC patients treated with TACE and determined the factors that affect the overall survival.

Methods

We included 266 patients who were older than 65 years and had received TACE as initial treatment for HCC. We analyzed the skeletal muscle index (SMI) and visceral-to-subcutaneous fat ratio (VSR) around the third lumbar vertebrae using computed tomography scans. Muscle depletion with visceral adiposity (MDVA) was defined by falling below the median SMI and above the median VSR value sex-specifically. We evaluated the overall survival in association with MDVA and other clinical factors.

Results

The mean age was 69.9 ± 4.5 years, and 70.3% of the patients were men. According to the Barcelona Clinic Liver Cancer (BCLC) staging system, 29, 136, and 101 patients were classified as BCLC 0, A, and B stages, respectively, and 79 (29.7%) had MDVA. During the median follow-up of 4.1 years, patients with MDVA had a shorter life expectancy than those without MDVA (P = 0.007) even though MDVA group had a higher objective response rate after the first TACE (82.3% vs. 75.9%, P = 0.035). Multivariate analysis revealed that MDVA (Hazard ratio [HR] 1.515) age (HR 1.057), liver function (HR 1.078), tumor size (HR 1.083), serum albumin level (HR 0.523), platelet count (HR 0.996), tumor stage (stage A, HR 1.711; stage B, HR 2.003), and treatment response after the first TACE treatment (HR 0.680) were associated with overall survival.

Conclusions

MDVA is a critical prognostic factor for predicting survival in the elderly patients with HCC who have undergone TACE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08905-2.

Physical Activity Interventions for Colorectal Cancer Survivors: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

Physical activity (PA) has been shown to improve total mortality and colorectal-specific mortality risk; however, colorectal cancer (CRC) survivors have lower rates of PA compared with survivors with other types of cancers.

Objective

To examine the effect of PA interventions on CRC survivors.

Methods

A systematic review and meta-analysis were conducted to identify randomized controlled trials that met the inclusion criteria, which included an intervention designed to increase PA and more than 1 outcome of interest. Random effects of the meta-analyses were performed using Review Manager 5.3.

Results

Eight publications representing 7 randomized controlled trials of 803 participants were identified. All studies used a combination of behavioral change methods. Physical activity interventions significantly improved disease-specific quality of life, PA level, and maximum amount of oxygen and did not show significant improvements for fatigue and body mass index among CRC survivors.

Conclusions

We provided evidence that PA interventions were effective in improving disease-specific quality of life, PA level, and maximum amount of oxygen; however, they did not improve fatigue and body mass index. Further randomized controlled trials are needed to determine the optimal mode of delivering PA intervention for CRC survivors.

Implications for Practice

As the survival rate of patients with CRC increases, survivors of CRC need to increase PA in a community setting after completing primary treatments. Effective and efficient modes of PA intervention delivery could improve health-related outcomes and address specific barriers for CRC survivors.

Fasting and Exercise in Oncology: Potential Synergism of Combined Interventions

Nutrition and exercise interventions are strongly recommended for most cancer patients; however, much debate exists about the best prescription. Combining fasting with exercise is relatively untouched within the oncology setting. Separately, fasting has demonstrated reductions in chemotherapy-related side effects and improved treatment tolerability and effectiveness. Emerging evidence suggests fasting may have a protective effect on healthy cells allowing chemotherapy to exclusively target cancer cells. Exercise is commonly recommended and attenuates treatment- and cancer-related adverse changes to body composition, quality of life, and physical function. Given their independent benefits, in combination, fasting and exercise may induce synergistic effects and further improve cancer-related outcomes. In this narrative review, we provide a critical appraisal of the current evidence of fasting and exercise as independent interventions in the cancer population and discuss the potential benefits and mechanisms of combined fasting and exercise on cardiometabolic, body composition, patient-reported outcomes, and cancer-related outcomes. Our findings suggest that within the non-cancer population combined fasting and exercise is a viable strategy to improve health-related outcomes, however, its safety and efficacy in the oncology setting remain unknown. Therefore, we also provide a discussion on potential safety issues and considerations for future research in the growing cancer population.

Physical Activity Reduces the Risk of Recurrence and Mortality in Cancer Patients

The biological mechanisms through which physical activity reduces metastatic disease recurrence and mortality in cancer patients are not known. This review offers the hypothesis that physical activity reduces the risk of recurrence and mortality in cancer patients through two synergistic processes: 1) indirect (systemic) effects related to the host tumor microenvironment; and 2) direct (physical) effects on cancer cells.

Association of a Preoperative Leisure-Time Physical Activity With Short- and Long-term Outcomes of Patients Undergoing Curative Resection for Stage I to III Colorectal Cancer: A Propensity Score Matching Analysis

BACKGROUND

Physical activity might be directly or indirectly linked to the risk of colorectal cancer and the prognosis of patients with colorectal cancer.

OBJECTIVE

This study aimed to elucidate whether preoperative physical activity plays a role in reducing short-term postoperative complications and improving long-term survival of patients with colorectal cancer.

DESIGN

This was a retrospective analysis of prospectively collected data.

SETTINGS

This study was conducted at a department of colorectal surgery in a tertiary teaching hospital between January 1995 and December 2016.

PATIENTS

Patients who underwent curative resection for stage I to III primary colorectal cancer were enrolled. According to the preoperative leisure-time weekly metabolic equivalent of task values, patients were divided into 2 groups: the metabolic equivalent of task <12 group and the metabolic equivalent of task ≥12 group. A 1:1 propensity score matching was used to reduce imbalance and selection biases based on 6 covariates, namely, age, sex, BMI, tumor location, tumor stage, and adjuvant chemotherapy administration.

MAIN OUTCOME MEASURES

χ tests were used to analyze short-term postoperative complications. Kaplan-Meier analyses were used to evaluate disease-free survival and overall survival.

RESULTS

In the matched cohort patients, significant differences in overall postoperative complications and mortality were observed in favor of the metabolic equivalent of task ≥12 group, although there was no difference in any single item of postoperative morbidity. The results of the Kaplan-Meier analysis and log-rank test demonstrated a significant survival benefit in the metabolic equivalent of task ≥12 group compared with the metabolic equivalent of task <12 group both for disease-free and overall survival.

LIMITATIONS

This study is limited by its retrospective nature.

CONCLUSIONS

This single-institute study provides evidence of the association of preoperative leisure-time physical activity with short-term postoperative morbidity and mortality, as well as long-term survival. See Video Abstract at http://links.lww.com/DCR/B189. ASOCIACIÓN DE ACTIVIDAD FÍSICA DE TIEMPO LIBRE PREOPERATORIA CON RESULTADOS A CORTO Y LARGO PLAZO DE PACIENTES SOMETIDOS A RESECCIÓN CURATIVA POR CÁNCER COLORRECTAL EN ESTADIO I-III: UN ANÁLISIS DE COINCIDENCIA DE PUNTAJE DE PROPENSIÓN ANTECEDENTES: LA ACTIVIDAD FíSICA PUEDE ESTAR DIRECTA O INDIRECTAMENTE RELACIONADA CON EL RIESGO DE CÁNCER COLORRECTAL Y EL PRONÓSTICO DE LOS PACIENTES CON CÁNCER COLORRECTAL.: Este estudio tuvo como objetivo dilucidar si la actividad física preoperatoria desempeña un papel en la reducción de las complicaciones postoperatorias a corto plazo y en mejorar la supervivencia a largo plazo de los pacientes con cáncer colorrectal.Este fue un análisis retrospectivo de datos recolectados prospectivamente.Este estudio se realizó en un departamento de cirugía colorrectal en un hospital universitario terciario entre Enero de 1995 y Diciembre de 2016.Se incluyeron pacientes sometidos a resección curativa por cáncer colorrectal primario en estadio I-III. De acuerdo con el equivalente metabólico semanal en el tiempo libre de los valores de la tarea preoperatorio, los pacientes se dividieron en dos grupos: el equivalente metabólico del grupo de tarea <12 y el equivalente metabólico del grupo de tarea ≥ 12. Se utilizó una coincidencia de puntaje de propensión 1: 1 para reducir los desequilibrios y los sesgos de selección basados en seis covariables, principalmente, edad, sexo, índice de masa corporal, ubicación del tumor, estadio del tumor y administración de quimioterapia adyuvante.Las pruebas de Chi-cuadrado se utilizaron para analizar las complicaciones postoperatorias a corto plazo. Los análisis de Kaplan-Meier se utilizaron para evaluar la supervivencia libre de enfermedad y la supervivencia general.en los pacientes de la cohorte emparejada, se observaron diferencias significativas en las complicaciones postoperatorias generales y la mortalidad a favor del equivalente metabólico del grupo de tareas ≥ 12, aunque no hubo diferencias en ningún elemento único de morbilidad postoperatoria. Los resultados del análisis de Kaplan-Meier y la prueba de log-rank demostraron un beneficio de supervivencia significativo en el equivalente metabólico del grupo tarea ≥ 12 en comparación con el equivalente metabólico del grupo tarea <12 tanto para la supervivencia libre de enfermedad como para la supervivencia general.Este estudio está limitado por su naturaleza retrospectiva.Este estudio de instituto único proporciona evidencia de la asociación de la actividad física preoperatoria en el tiempo libre con la morbilidad y mortalidad postoperatorias a corto plazo, así como la supervivencia a largo plazo. Consulte Video Resumen en http://links.lww.com/DCR/B189. (Traducción-Dr. Yesenia Rojas-Kahlil).

Physical activity interventions for disease-related physical and mental health during and following treatment in people with non-advanced colorectal cancer

BACKGROUND

Colorectal cancer is the third most commonly diagnosed cancer worldwide. A diagnosis of colorectal cancer and subsequent treatment can adversely affect an individuals physical and mental health. Benefits of physical activity interventions in alleviating treatment side effects have been demonstrated in other cancer populations. Given that regular physical activity can decrease the risk of colorectal cancer, and cardiovascular fitness is a strong predictor of all-cause and cancer mortality risk, physical activity interventions may have a role to play in the colorectal cancer control continuum. Evidence of the efficacy of physical activity interventions in this population remains unclear.

OBJECTIVES

To assess the effectiveness and safety of physical activity interventions on the disease-related physical and mental health of individuals diagnosed with non-advanced colorectal cancer, staged as T1-4 N0-2 M0, treated surgically or with neoadjuvant or adjuvant therapy (i.e. chemotherapy, radiotherapy or chemoradiotherapy), or both.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 6), along with OVID MEDLINE, six other databases and four trial registries with no language or date restrictions. We screened reference lists of relevant publications and handsearched meeting abstracts and conference proceedings of relevant organisations for additional relevant studies. All searches were completed between 6 June and 14 June 2019.

SELECTION CRITERIA

We included randomised control trials (RCTs) and cluster-RCTs comparing physical activity interventions, to usual care or no physical activity intervention in adults with non-advanced colorectal cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, performed the data extraction, assessed the risk of bias and rated the quality of the studies using GRADE criteria. We pooled data for meta-analyses by length of follow-up, reported as mean differences (MDs) or standardised mean differences (SMDs) using random-effects wherever possible, or the fixed-effect model, where appropriate. If a meta-analysis was not possible, we synthesised studies narratively.

MAIN RESULTS

We identified 16 RCTs, involving 992 participants; 524 were allocated to a physical activity intervention group and 468 to a usual care control group. The mean age of participants ranged between 51 and 69 years. Ten studies included participants who had finished active treatment, two studies included participants who were receiving active treatment, two studies included both those receiving and finished active treatment. It was unclear whether participants were receiving or finished treatment in two studies. Type, setting and duration of physical activity intervention varied between trials. Three studies opted for supervised interventions, five for home-based self-directed interventions and seven studies opted for a combination of supervised and self-directed programmes. One study did not report the intervention setting. The most common intervention duration was 12 weeks (7 studies). Type of physical activity included walking, cycling, resistance exercise, yoga and core stabilisation exercise. Most of the uncertainty in judging study bias came from a lack of clarity around allocation concealment and blinding of outcome assessors. Blinding of participants and personnel was not possible. The quality of the evidence ranged from very low to moderate overall. We did not pool physical function results at immediate-term follow-up due to considerable variation in results and inconsistency of direction of effect. We are uncertain whether physical activity interventions improve physical function compared with usual care. We found no evidence of effect of physical activity interventions compared to usual care on disease-related mental health (anxiety: SMD -0.11, 95% confidence interval (CI) -0.40 to 0.18; 4 studies, 198 participants; I2 = 0%; and depression: SMD -0.21, 95% CI -0.50 to 0.08; 4 studies, 198 participants; I2 = 0%; moderate-quality evidence) at short- or medium-term follow-up. Seven studies reported on adverse events. We did not pool adverse events due to inconsistency in reporting and measurement. We found no evidence of serious adverse events in the intervention or usual care groups. Minor adverse events, such as neck, back and muscle pain were most commonly reported. No studies reported on overall survival or recurrence-free survival and no studies assessed outcomes at long-term follow-up We found evidence of positive effects of physical activity interventions on the aerobic fitness component of physical fitness (SMD 0.82, 95% CI 0.34 to 1.29; 7 studies, 295; I2 = 68%; low-quality evidence), cancer-related fatigue (MD 2.16, 95% CI 0.18 to 4.15; 6 studies, 230 participants; I2 = 18%; low-quality evidence) and health-related quality of life (SMD 0.36, 95% CI 0.10 to 0.62; 6 studies, 230 participants; I2 = 0%; moderate-quality evidence) at immediate-term follow-up. These positive effects were also observed at short-term follow-up but not medium-term follow-up. Only three studies reported medium-term follow-up for cancer-related fatigue and health-related quality of life.

AUTHORS' CONCLUSIONS

The findings of this review should be interpreted with caution due to the low number of studies included and the quality of the evidence. We are uncertain whether physical activity interventions improve physical function. Physical activity interventions may have no effect on disease-related mental health. Physical activity interventions may be beneficial for aerobic fitness, cancer-related fatigue and health-related quality of life up to six months follow-up. Where reported, adverse events were generally minor. Adequately powered RCTs of high methodological quality with longer-term follow-up are required to assess the effect of physical activity interventions on the disease-related physical and mental health and on survival of people with non-advanced colorectal cancer. Adverse events should be adequately reported.

Exercise as a prescription for patients with various diseases

A growing understanding of the benefits of exercise over the past few decades has prompted researchers to take an interest in the possibilities of exercise therapy. Because each sport has its own set of characteristics and physiological complications that tend to occur during exercise training, the effects and underlying mechanisms of exercise remain unclear. Thus, the first step in probing the effects of exercise on different diseases is the selection of an optimal exercise protocol. This review summarizes the latest exercise prescription treatments for 26 different diseases: musculoskeletal system diseases (low back pain, tendon injury, osteoporosis, osteoarthritis, and hip fracture), metabolic system diseases (obesity, type 2 diabetes, type 1 diabetes, and nonalcoholic fatty liver disease), cardio-cerebral vascular system diseases (coronary artery disease, stroke, and chronic heart failure), nervous system diseases (Parkinson's disease, Huntington's disease, Alzheimer's disease, depression, and anxiety disorders), respiratory system diseases (chronic obstructive pulmonary disease, interstitial lung disease, and after lung transplantation), urinary system diseases (chronic kidney disease and after kidney transplantation), and cancers (breast cancer, colon cancer, prostate cancer, and lung cancer). Each exercise prescription is displayed in a corresponding table. The recommended type, intensity, and frequency of exercise prescriptions are summarized, and the effects of exercise therapy on the prevention and rehabilitation of different diseases are discussed.

Exercise-induced hypoalgesia: A meta-analysis of exercise dosing for the treatment of chronic pain

OBJECTIVE

Increasing evidence purports exercise as a first-line therapeutic for the treatment of nearly all forms of chronic pain. However, knowledge of efficacious dosing respective to treatment modality and pain condition is virtually absent in the literature. The purpose of this analysis was to calculate the extent to which exercise treatment shows dose-dependent effects similar to what is seen with pharmacological treatments.

METHODS

A recently published comprehensive review of exercise and physical activity for chronic pain in adults was identified in May 2017. This report reviewed different physical activity and exercise interventions and their effectiveness in reducing pain severity and found overall modest effects of exercise in the treatment of pain. We analyzed this existing data set, focusing specifically on the dose of exercise intervention in these studies. We re-analyzed data from 75 studies looking at benefits of time of exercising per week, frequency of exercise per week, duration of intervention (in weeks), and estimated intensity of exercise.

RESULTS

Analysis revealed a significant positive correlation with exercise duration and analgesic effect on neck pain. Multiple linear regression modeling of these data predicted that increasing the frequency of exercise sessions per week is most likely to have a positive effect on chronic pain patients.

DISCUSSION

Modest effects were observed with one significant correlation between duration and pain effect for neck pain. Overall, these results provide insufficient evidence to conclude the presence of a strong dose effect of exercise in pain, but our modeling data provide tes predictions that can be used to design future studies to explicitly test the question of dose in specific patient populations.

The evolution of body composition in oncology-epidemiology, clinical trials, and the future of patient care: facts and numbers

There is growing interest from the oncology community to understand how body composition measures can be used to improve the delivery of clinical care for the 18.1 million individuals diagnosed with cancer annually. Methods that distinguish muscle from subcutaneous and visceral adipose tissue, such as computed tomography (CT), may offer new insights of important risk factors and improved prognostication of outcomes over alternative measures such as body mass index. In a meta-analysis of 38 studies, low muscle area assessed from clinically acquired CT was observed in 27.7% of patients with cancer and associated with poorer overall survival [hazard ratio: 1.44, 95% CI: 1.32-1.56]. Therapeutic interventions such as lifestyle and pharmacotherapy that modify all aspects of body composition and reduce the incidence of poor clinical outcomes are needed in patients with cancer. In a meta-analysis of six randomized trials, resistance training exercise increased lean body mass assessed from dual-energy X-ray absorptiometry [mean difference (MD): +1.07 kg, 95% CI: 0.76-1.37; P < 0.001] and walking distance [MD: +143 m, 95% CI: 70-216; P < 0.001] compared with usual care control in patients with non-metastatic cancer. In a meta-analysis of five randomized trials, anamorelin (a ghrelin agonist) significantly increased lean body mass [MD: +1.10 kg, 95% CI: 0.35-1.85; P = 0.004] but did not improve handgrip strength [MD: 0.52 kg, 95% CI: -0.09-1.13; P = 0.09] or overall survival compared with placebo [HR: 0.99, 95% CI: 0.85-1.14; P = 0.84] in patients with advanced or metastatic cancer. Early screening to identify individuals with occult muscle loss, combined with multimodal interventions that include lifestyle therapy with resistance exercise training and dietary supplementation combined with pharmacotherapy, may be necessary to provide a sufficient stimulus to prevent or slow the cascade of tissue wasting. Rapid, cost-efficient, and feasible methods to quantify muscle and adipose tissue distribution are needed if body composition assessment is to be integrated into large-scale clinical workflows. Fully automated analysis of body composition from clinically acquired imaging is one example. The study of body composition is one of the most provocative areas in oncology that offers tremendous promise to help patients with cancer live longer and healthier lives.

Energy balance and gastrointestinal cancer: risk, interventions, outcomes and mechanisms

Obesity increases the risk of multiple gastrointestinal cancers and worsens disease outcomes. Conversely, strong inverse associations have emerged between physical activity and colon cancer and possibly other gastrointestinal malignancies. The effect of weight loss interventions - such as modifications of diet and/or physical activity or bariatric surgery - remains unclear in patients who are obese and have gastrointestinal cancer, although large clinical trials are underway. Human intervention studies have already shed light on potential mechanisms underlying the energy balance-cancer relationship, with preclinical models supporting emerging pathway effects. Central to interventions that reduce obesity or increase physical activity are pluripotent cancer-preventive effects (including reduced systemic and adipose tissue inflammation and angiogenesis, altered adipokine levels and improved insulin resistance) that directly interface with the hallmarks of cancer. Other mechanisms, such as DNA repair, oxidative stress and telomere length, immune function, effects on cancer stem cells and the microbiome, could also contribute to energy balance effects on gastrointestinal cancers. Although some mechanisms are well understood (for instance, systemic effects on inflammation and insulin signalling), other areas remain unclear. The current state of knowledge supports the need to better integrate mechanistic approaches with preclinical and human studies to develop effective, personalized diet and exercise interventions to reduce the burden of obesity on gastrointestinal cancer.

Effects of exercise on circulating tumor cells among patients with resected stage I-III colon cancer

BACKGROUND

Physical activity is associated with a lower risk of disease recurrence among colon cancer patients. Circulating tumor cells (CTC) are prognostic of disease recurrence among stage I-III colon cancer patients. The pathways through which physical activity may alter disease outcomes are unknown, but may be mediated by changes in CTCs.

METHODS

Participants included 23 stage I-III colon cancer patients randomized into one of three groups: usual-care control, 150 min∙wk-1 of aerobic exercise (low-dose), and 300 min∙wk-1 of aerobic exercise (high-dose) for six months. CTCs from venous blood were quantified in a blinded fashion using an established microfluidic antibody-mediated capture device. Poisson regression models estimated the logarithmic counts of CTCs.

RESULTS

At baseline, 78% (18/23) of patients had ≥1 CTC. At baseline, older age (-0.12±0.06; P = 0.04), lymphovascular invasion (0.63±0.25; P = 0.012), moderate/poor histology (1.09±0.34; P = 0.001), body mass index (0.07±0.02; P = 0.001), visceral adipose tissue (0.08±0.04; P = 0.036), insulin (0.06±0.02; P = 0.011), sICAM-1 (0.04±0.02; P = 0.037), and sVCAM-1 (0.06±0.03; P = 0.045) were associated with CTCs. Over six months, significant decreases in CTCs were observed in the low-dose (-1.34±0.34; P<0.001) and high-dose (-1.18±0.40; P = 0.004) exercise groups, whereas no significant change was observed in the control group (-0.59±0.56; P = 0.292). Over six months, reductions in body mass index (-0.07±0.02; P = 0.007), insulin (-0.08±0.03; P = 0.014), and sICAM-1 (-0.07±0.03; P = 0.005) were associated with reductions in CTCs. The main limitations of this proof-of-concept study are the small sample size, heterogenous population, and per-protocol statistical analysis.

CONCLUSION

Exercise may reduce CTCs among stage I-III colon cancer patients. Changes in host factors correlated with changes in CTCs. Exercise may have a direct effect on CTCs and indirect effects through alterations in host factors. This hypothesis-generating observation derived from a small pilot study warrants further investigation and replication.

Integrative Treatment for Colorectal Cancer: A Comprehensive Approach

A comprehensive approach to integrative treatment of colorectal cancer (CRC) patients involves three spheres of intervention: lifestyle, biology, and conventional treatment. Individualization of treatment is emphasized. The lifestyle sphere includes nutritional therapies, biobehavioral strategies with circadian interventions, and physical care modalities. The biology sphere comprises six host factors in the patient's internal biochemical environment or "terrain": inflammation, glycemia, oxidative stress, immune dysregulation, coagulopathy, and stress chemistries. Laboratory testing of these factors guides integrative lifestyle and supplement recommendations. The conventional treatment sphere includes individualized lifestyle recommendations, and supplements or drugs used to enhance tolerability or effectiveness of conventional treatments. Innovative strategies are implemented, including chronomodulated chemotherapy, chemosensitivity testing, and using results of molecular genomic testing to guide nutritional infusions and supplement recommendations. In the lifestyle sphere, substantial evidence from cohort studies supports recommendations for a diet that emphasizes plant and fish proteins, healthful fats in amounts that are tailored to the clinical circumstance of the patient, and carbohydrates based on unrefined whole grains, vegetables and whole fruits. High glycemic diets and refined carbohydrates, especially sugar-sweetened beverages, should be avoided. Biobehavioral strategies include practice of the relaxation response and related approaches. In addition, specific strategies to promote robust circadian organization (CO) are used to combat quality of life concerns and worsened survival that accompany disrupted CO. Physical activity, including aerobic activity and muscle strengthening, is recommended at all disease stages. In the biology sphere, supplements and lifestyle recommendations for inflammation and glycemia are discussed. In the conventional treatment sphere, supplements and innovative and complementary therapies that may remedy treatment toxicities are reviewed. Approaching CRC treatment with a comprehensive, individualized intervention enables safe and beneficial outcomes in this patient population, which can vary widely in individual biology, treatment toxicities, and disease complications. Further research in integrative therapies for CRC patients is needed.

PGC-1α as a Biomarker of Physical Activity-Protective Effect on Colorectal Cancer

Colorectal cancer is a significant public health concern. As a multistage and multifactorial disease, environmental and genetic factors interact at each stage of the process, and an individual's lifestyle also plays a relevant role. We set out to review the scientific evidence to study the need to investigate the role of the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) gene as a biomarker of the physical activity's (PA) effect on colorectal cancer. PA is a protective factor against colorectal cancer and usually increases the expression of PGC-1α This gene has pleiotropic roles and is the main regulator of mitochondrial functions. The development of colorectal cancer has been associated with mitochondrial dysfunction; in addition, alterations in this organelle are associated with colorectal cancer risk factors, such as obesity, decreased muscle mass, and the aging process. These are affected by PA acting, among other aspects, on insulin sensitivity and oxygen reactive species/redox balance. Therefore, this gene demands special attention in the understanding of its operation in the consensual protective effect of PA in colorectal cancer. A significant amount of indirect evidence points to PGC-1α as a potential biomarker in the PA-protective effect on colorectal cancer. The article focuses on the possible involvement of PGC-1α in the protective role that physical activity has on colorectal cancer. This is an important topic both in relation to advances in prevention of the development of this widespread disease and in its therapeutic treatment. We hope to generate an initial hypothesis for future studies associated with physical activity-related mechanisms that may be involved in the development or prevention of colorectal cancer. PGC-1α is highlighted because it is the main regulator of mitochondrial functions. This organelle, on one hand, is positively stimulated by physical activity; on the other hand, its dysfunction or reduction increases the probability of developing colorectal cancer. Therefore, we consider the compilation of existing information about the possible ways to understand the mechanisms of this gene to be highly relevant. This study is based on evidence of PGC-1α and physical activity, on PGC-1α and colorectal cancer, on colorectal cancer and physical activity/inactivity, and the absence of studies that have sought to relate all of these variables. Cancer Prev Res; 11(9); 523-34. ©2018 AACR.

A randomized dose-response trial of aerobic exercise and health-related quality of life in colon cancer survivors

OBJECTIVE

To examine the dose-response effects of aerobic exercise on health-related quality of life (HRQoL) among colon cancer survivors.

METHODS

Thirty-nine stage I to III colon cancer survivors were randomized to 1 of 3 groups: usual-care control, 150 min·wk-1 of aerobic exercise (low-dose) and 300 min·wk-1 of aerobic exercise (high-dose) for 6 months. HRQoL outcomes included the Short Form (SF)-36 physical and mental component summary, Functional Assessment of Cancer Therapy-Colorectal, Pittsburgh Sleep Quality Index, Fear of Cancer Recurrence Inventory, Fatigue Symptom Inventory, and North Central Cancer Treatment Group bowel function questionnaire, assessed at baseline and post intervention. The primary hypothesis was that exercise would improve HRQoL outcomes in a dose-response fashion, such that high-dose aerobic exercise would yield the largest improvements in HRQoL outcomes.

RESULTS

Over 6 months, the low-dose group completed 141 ± 10 min·wk-1 of aerobic exercise, and the high-dose group completed 247 ± 11 min·wk-1 of aerobic exercise. Over 6 months, exercise improved the physical component summary score of the SF-36 (Ptrend  = 0.002), the Functional Assessment of Cancer Therapy-Colorectal (Ptrend  = 0.025), the Pittsburgh Sleep Quality Index (Ptrend  = 0.049), and the Fatigue Symptom Inventory (Ptrend  = 0.045) in a dose-response fashion. Between-group standardized mean difference effects sizes for the above-described findings were small to moderate in magnitude (0.35-0.75). No dose-response effects were observed for the mental component summary score of the SF-36, the Fear of Cancer Recurrence Inventory, or bowel function.

CONCLUSION

Higher doses of aerobic exercise, up to 300 min·wk-1 , improve multiple HRQoL outcomes among stage I to III colon cancer survivors. These findings provide evidence that aerobic exercise may provide multiple health benefits for colon cancer survivors.

Dose-response effects of exercise on insulin among colon cancer survivors

Physical activity is associated with a lower risk of disease recurrence among colon cancer survivors. The pathways through which physical activity may alter disease outcomes are unknown, but may include changes in metabolic growth factors, such as insulin. Between January 2015 and August 2015, 39 stage I-III colon cancer survivors were randomized to one of the three groups: usual care control, 150 min/week of aerobic exercise (low-dose) and 300 min/week of aerobic exercise (high-dose) for six months. The pre-specified key metabolic growth factor outcome was fasting insulin. Insulin resistance was quantified using the homeostatic model assessment. Mean age was 56.5 ± 10.0 years, 51% had stage III disease, 72% were treated with chemotherapy and the mean time since finishing treatment was 10.9 ± 6.1 months. Over six months, the low-dose group completed 141.5 ± 9.9 min/week of aerobic exercise, and the high-dose group completed 247.2 ± 10.7 min/week of aerobic exercise. Fasting insulin concentrations decreased 7.4 ± 9.4 pmol/L in the control group, 28.0 ± 8.3 pmol/L in the low-dose group and 20.7 ± 9.3 pmol/L in the high-dose group (nonlinear Ptrend = 0.042). Insulin resistance decreased 0.11 ± 0.20 in the control group, 0.63 ± 0.17 in the low-dose group and 0.43 ± 0.19 in the high-dose group (nonlinear Ptrend = 0.012). Aerobic exercise reduces insulin concentrations and insulin resistance among patients with stage I-III colon cancer. Prescribing 150 min/week of aerobic exercise may be sufficient for reducing insulin concentrations and insulin resistance, which may partially mediate the relationship between physical activity and colon cancer prognosis.