Exercise Ups Cancer Survival; A Little Goes A Long Way

Kristin Jenkins

December 20, 2018

Exercise after a cancer diagnosis improves survival, even in patients who had not exercised previously, concludes a new study. 

The findings come from an analysis of detailed epidemiological data collected over 14 years from a cohort of 5807 patients who were diagnosed with a variety of cancers.

A significant survival benefit of exercise was seen in patients with one of eight specific tumors, including breast, colon, prostate, ovarian, bladder, endometrial, esophageal, and skin cancer (mostly melanoma).

Regular exercisers had the biggest survival advantage over their sedentary peers. Patients who exercised three to four times each week before and after their cancer diagnosis reduced their all-cause mortality risk by 40% (hazard ratio [HR], 0.60) and their cancer-specific mortality risk by 39% (HR, 0.61) compared with cancer patients who remained "habitually inactive."

However, patients who exercised just 1 or 2 days each week before and after their cancer diagnosis also had significantly improved survival compared with their sedentary counterparts. They enjoyed a 32% reduction in both all-cause mortality and cancer-specific mortality (HR, 0.68), the study showed.

Astonishingly, even veteran couch potatoes experienced dramatically improved survival when they exercised. The researchers found that patients who were sedentary in the decade prior to diagnosis experienced a 28% drop in all-cause and cancer-specific mortality when they exercised just one to two times a week in the year following cancer diagnosis (HR, 0.72).

The survival benefits were observed regardless of the patient's sex, age, weight, smoking status, or cancer stage.

"In other words, the association was seen in obese patients, persistent smokers, and in patients who were diagnosed with advanced-stage tumors," lead author Rikki A. Cannioto, PhD, assistant professor of oncology at Roswell Park Comprehensive Cancer Center in Buffalo, New York, told Medscape Medical News.

The study was published online on November 28 in Cancer Causes & Control.

It is never too late to make healthy lifestyle changes that may affect the survival trajectory.    Rikki Cannioto, PhD

These findings indicate that "it is never too late to make healthy lifestyle changes that may affect the survival trajectory," said Cannioto. "This is good news for all cancer patients."

"Collectively, these observations solidify the clinical and public health importance of the message that any amount of regular weekly activity is better than inactivity," the authors write. This is "particularly encouraging," they add, "given that cancer patients and survivors can be overwhelmed by the current physical activity recommendations of 30 minutes per day of moderate-intensity physical activity."

The study population, which was primarily white, included more women than men (55% versus 45%). A total of 1390 patients (24.4%) said they did not exercise regularly prior to diagnosis and 2400 (41.9%) said they did not exercise after cancer diagnosis.

The authors acknowledge that self-reported physical activity is a "primary limitation of our study," as it may be subject to recall error and misclassification, especially for the decade prior to diagnosis.

Implementing Exercise Into Supportive Care?

"These data demonstrate the potential value of implementing exercise into the supportive care continuum of cancer patients and can inform targeted intervention trials designed to improve clinical outcomes among patients diagnosed with a variety of malignancies," the authors note.

Oncologists should counsel patients about the survival benefits of physical activity and encourage them to take advantage of resources within the healthcare system and in the community, Cannioto suggested. A referral to physical therapy can address specific mobility issues, and there are many community resources such as the YMCA, which offers a free exercise program for cancer patients, she noted.

However, there has been concern expressed about how the exercise needs of seriously ill cancer patients can be balanced without creating additional health risks, as for example, in an editorial published earlier this year in Lancet Oncology.

The (unnamed) editorialists noted that when the Clinical Oncology Society of Australia (COSA) released its position statement in May recommending that all patients with cancer be prescribed exercise as part of their treatment regimen, the move was endorsed by no less than 25 leading healthcare institutions. The recommendations of the COSA exercise guidelines were previously reported by Medscape Medical News.

Despite widespread endorsement for incorporating exercise into cancer survivorship, "it would be naive to think that there can, or should, be a one-size-fits-all approach to suit all patients," the editorialists wrote.

"Patient comorbidities and fragility need to be adequately considered when recommending the feasibility of any physical activity regimen," they added.  

In an accompanying correspondence column, a research team from the Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada, agreed that common comorbidities and treatment side effects can increase risk in patients who would otherwise benefit from exercise.

Current exercise guidelines for cancer patients are geared primarily to the general public "with some cancer-specific caveats," wrote Daniel Santa Mina, PhD, assistant professor in the Faculty of Kinesiology and Physical Education, University of Toronto, and colleagues.

As such, these guidelines "fall short of effectively advising clinicians and qualified exercise professionals about how to identify and manage many potential exercise contraindications, especially given the high degree of heterogeneity in patient risks and comorbidities," the authors emphasized.

To address these barriers to exercise, the researchers have developed a clinical "if yes, then" tool that provides clinicians with evidence-based directives for common exercise contraindications.

The Safety Reference Guide can be used in conjunction with guidelines from the American College of Sports Medicine and COSA to standardize risk management and determine exercise precautions. Ultimately, it allows clinicians to tailor safe, individualized workouts for cancer patients who might otherwise be excluded from the full benefits of an exercise prescription.

The guide is now part of an 8-week, medically supervised Cancer Rehabilitation and Exercise (CaRE) program at Princess Margaret Hospital for patients with active cancer-related impairments such as fatigue, deconditioning, lymphedema, or general or localized dysfunction.

The study of the cancer survival benefits of exercise was funded by the Roswell Park Cancer Center and National Cancer Institute. Cannioto, Santa Mina, and co-authors have reported no relevant financial relationships.

Cancer Causes Control. Published online November 28, 2018. Abstract

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