Engaging in regular physical activity before and after a cancer diagnosis can dramatically improve survival rates in patients with certain types of tumors, according to a large-scale study by researchers at Roswell Park Comprehensive Cancer Center, Buffalo, N.Y.
"There are not a lot of studies that measure the benefits of physical activity before and after a diagnosis-at least for numerous or less-common cancers," said lead author, Rikki Cannioto, PhD, EdD, MS, Assistant Professor of Oncology in the Department of Cancer Prevention and Control.
The current study suggests that regular exercise can drastically reduce mortality rate among patients diagnosed with breast, colon, prostate, bladder, endometrial, ovarian, esophageal, and skin cancer. The results remained consistent, independent of sex, tumor stage, body mass index, or smoking status.
A growing body of evidence shows that a physically active lifestyle reduces the risk of many diseases, including cancer, the team noted. Moreover, established research demonstrates the link between physical activity and increased survival odds among patients with more common types of cancer-breast, colorectal, and prostate. The Roswell Park study has uncovered associations among less commonly studied tumors.
While previous studies led by Cannioto have shown a strong link between lifetime inactivity and increased risk of particular cancers, the new findings are among the first to demonstrate an association of pre- and post-diagnosis activity with survival across several different cancer types, the research team noted.
Study Methodology
Cannioto and colleagues examined the association between physical activity and cancer mortality among 5,807 cancer patients enrolled in Roswell Park's Data Bank and BioRepository between 2003 and 2016. Participants self-reported physical activity levels in the 10 years prior to study enrollment, as well as 1 year afterward.
Patients were diagnosed with numerous malignancies, including bladder, breast, colorectal, esophageal, endometrial, head and neck, hematological, kidney, liver, lung, ovarian, pancreas, prostate, skin, and stomach cancers.
Cancer patients who engaged in regular, weekly, moderate- to vigorous-intensity physical activity (such as walking, running, aerobics, or other cardiovascular exercise) before and after their diagnosis were considered habitually active; those who did not exercise regularly were considered habitually inactive. The study also included patients who engaged in activity only before diagnosis (decreased activity), as well as those who solely became active after diagnosis (increased activity).
Investigators followed participants from Jan. 1, 2003 through Jan. 31, 2018, with an average follow-up of 53 months. About one-third of patients-1,956 participants-died during the follow-up period. The cohort was primarily white, 54.8 percent female, and 45.2 percent male. Average age at diagnosis was 60.6 years.
Notable Results
Survival odds were up to 40 percent greater among patients who exercised before and after their diagnosis, the team noted. Those who were active 3-4 days a week-pre- and post-diagnosis-had the greatest survival advantage, Cannioto said.
"Strikingly, we also found that patients who only began to exercise after a cancer diagnosis increased survival odds by 28 percent," Cannioto said. The finding suggests that a cancer diagnosis might spur healthy behavior changes among some patients, the researchers noted; specifically, exercise after diagnosis can boost chances of survival.
"This result is particularly encouraging, as cancer patients and survivors can be overwhelmed by current physical activity recommendations. When it comes to beginning an exercise program, it's never too late," Cannioto noted.
Additionally, patients who engage in physical activity as little as 1-2 days a week before and after cancer diagnosis experienced similar survival advantages to those who exercised 5-7 days a week.
The next step, she noted, are prospective studies that focus on studying the effects of exercise interventions on quality of life and clinical outcomes among cancer survivors. Cannioto hopes to conduct a follow-up study among a similar patient population, outfitting participants with physical activity trackers.
"We still don't know what mechanisms explain the strong association between physical activity and improved prognosis among patients with certain types of cancer," she said.
Future Trends
Cannioto noted that her team's findings add to mounting exercise oncology research in scientific literature that demonstrates the "prognostic value of implementing exercise as part of the cancer care continuum."
While there are still many unanswered questions in the field, she said, research is moving toward conducting more prospective intervention trials that include objective methods to gauge physical activity.
"Much of the existing epidemiological literature reporting the associations of physical activity with cancer outcomes is based upon retrospective analysis of self-report physical activity questionnaire data, which can be associated with a high rate of error in reporting," Cannioto explained. "With the widespread availability of commercially available fitness trackers, researchers can now pair self-report data with objective data from activity trackers and can remotely follow patients for long periods of time after study enrollment."
Further research is needed to determine optimal frequency, intensity, duration, and kinds of exercise associated with the "greatest improvements in clinical outcomes," Cannioto said. "Additionally, more research is needed to understand the biological mechanisms underpinning the inverse association between physical activity and cancer mortality."
Karin Lillis is a contributing writer.