Roxanne Nelson, BSN, RN
CHICAGO — Cancer patients who are physically active both before and after treatment are 40% more likely to survive compared to those who are sedentary, according to new findings.
The association between physical activity and mortality was observed across eight cancer types. Importantly, the findings held after adjustment for sex, tumor stage, smoking status, and body mass index.
The results of the study were presented at the recent American Association for Cancer Research (AACR) 2018 Annual Meeting.
"Even though the significant association was seen in only eight of the tumor sites, the hazard ratio was below 1 in nearly every tumor site that we studied," said lead author Rikki Cannioto, PhD, EdD, assistant professor of oncology in the Department of Cancer Prevention and Control at Roswell Park Comprehensive Cancer Center, Buffalo, New York.
"From a practical standpoint, it looks like there's a survival advantage for all tumor types," she told Medscape Medical News. "We may not have been sufficiently powered to see a significance for all of them, but the take-home message is that there is a benefit for all cancer patients."
More importantly, Cannioto noted, was the improvement in survival among patients who had previously been sedentary. "Patients who reported never doing anything in terms of recreational activity in the decade prior to diagnosis, and then reported doing something around the time of diagnosis and afterwards, remarkably had about a 25% to 28% improvement in survival compared to those who remained inactive," she said. "We saw that starting physical activity after diagnosis is beneficial."
The message is that it's never too late to start exercising. - Dr Rikki Cannioto
"So the message is that it's never too late to start exercising," she added.
Even a Little Bit Helps
A growing body of evidence has linked physical activity with numerous benefits for cancer patients, including improvement in muscular strength, cardiovascular functioning, and quality of life, and some data suggest that it may confer a survival benefit in survivors.
One recent study, for example, found that among patients with stage III colon cancer whose lifestyle was considered highly consistent with the American Cancer Society guidelines on diet and exercise, there was a 42% lower relative risk for death.
In this study, Cannioto and colleagues examined the joint associations of pre- and postdiagnosis physical activity with mortality in 5807 patients who were diagnosed with cancer at Roswell Park Comprehensive Cancer Center from 2003 to 2016.
The cohort included slightly more women (54.8%) than men (45.2%). Most of the patients were white (93%), and the average age at diagnosis was 60.6 years. Diagnoses included malignancies of the bladder, breast, head and neck, kidney, liver, lung, ovaries, pancreas, prostate, skin, and stomach, as well as colorectal, esophageal, and endometrial cancers and hematologic malignancies.
Within this population, 25% reported not engaging in regular physical activity before their diagnosis; 42% reported not engaging in regular recreational exercise post diagnosis. Regarding habitual physical activity status, 52% reported being habitually active, 19% reported being habitually inactive, 23% reported decreased activity after diagnosis, and 6% reported increased activity after diagnosis.
In multivariable analyses, the greatest survival advantage was seen in patients who exercised 3 to 4 days/week before diagnosis (hazard ratio [HR], 0.66; P < .001) and 3 to 4 days/week after diagnosis (HR, 0.59; P < .001). Survival was virtually the same for patients who exercised 1 to 2 days/week both before diagnosis (HR, 0.77; P < .001) and after diagnosis (HR, 0.72; P < .001) and for those who exercised 5 to 7 days/week both before diagnosis (HR, 0.76; P < .001) and after diagnosis (HR, 0.73, P < .001).
This was another very important finding, commented Cannioto. "Patients who exercised 1 to 2 days a week experienced nearly identical survival as those who exercised more frequently — 5 to 7 times a week," she said. "Those patients who exercised 3 to 4 days a week did the best, but the take-away message is that low-frequency exercise was associated with a significant survival benefit. Patients who were exercising every day didn't do better."
These findings have been corroborated with other research. Cannioto pointed to a recent study about "weekend warriors" that found that for individuals who exercised for only one or two sessions a week, the risk for all-cause mortality and for death from cardiovascular disease or cancer was lower than for patients who never exercised.
"This is particularly encouraging, as cancer patients and survivors can be overwhelmed by current physical activity recommendations," she said.
Also in multivariable analyses, the hazard for mortality was 40% lower for patients who were habitually active compared to inactive patients (HR = 0.60; 95% confidence interval [CI], 0.54 - 0.68). When the patients who were habitually active were considered the referent group, the hazard for mortality was 66% higher in patients were inactive (HR = 1.66; 95% CI, 1.48 - 1.87).
Patients who increased their activity level after diagnosis experienced a 25% reduction in hazard of mortality (HR = 0.75, 95% CI, 0.61 - 0.92) compared with those who remained inactive.
Experts Weigh In
Two experts weighed in on the results.
Brian C. Focht, PhD, FACSM, CSCS, professor of kinesiology and director of the Exercise Behavioral Medicine Laboratory, Department of Human Sciences, College of Education and Human Ecology, Ohio State University, Columbus, noted that this study presents strong epidemiologic evidence of the benefits of physical activity for cancer patients. "It makes a meaningful contribution to the developing scientific literature supporting the value of implementing exercise/physical activity into supportive care of cancer patients," he said.
"As evidence like this accrues, I am hopeful that medical oncologists will continue to increasingly embrace the importance of both recommending and actively promoting lifestyle changes in physical activity, exercise, and healthy dietary habits to patients and survivors," Focht noted.
He pointed out that an "overarching challenge" is that best-practices approaches to integrating lifestyle interventions in supportive cancer care have yet to be established. "Nonetheless, as evidence continues to emerge, it becomes increasingly clear that promoting healthy lifestyle changes in exercise, physical activity, and dietary intake are important considerations in fostering improvements in key clinical and quality-of-life outcomes across the cancer control continuum," Focht added.
Erin L. Van Blarigan, ScD, assistant professor in the Department of Epidemiology and Biostatistics at the University of California, San Francisco, also agreed that these data add even more evidence to support the "very strong, consistent association that has been seen between physical activity and survival in individuals with cancer.
"Research has shown that receiving lifestyle counseling from their oncologist is a powerful motivator to make lifestyle changes for many patients, but unfortunately, this is not standard practice at many clinics," she said. She pointed out that both the American Cancer Society and the American College of Sports Medicine have published guidelines for cancer survivors that include specific types and amounts of physical activity that patients should aim for.
"Research is ongoing to determine what tools or resources, such as physical activity trackers, websites, and apps, may help support cancer patients in starting and maintaining a new exercise program," said Van Blarigan.
The study was funded by a grant from the Cancer Center Support Grant Shared Resource and was supported by a grant from the National Cancer Institute. Dr Cannioto, Dr Focht, and Dr Van Blarigan have disclosed no relevant financial relationships.
American Association for Cancer Research (AACR) 2018 Annual Meeting. Abstract 5254/9, presented April 18, 2018.