Cancer survivors who exercise often and intensively live longer, research suggests.
Cancer survivors who exercise often and intensively live longer, research suggests.
A Canadian and US analysis of almost 11,500 patients enrolled in a cancer screening trial, published in Cancer Prevention and Control, has found that the cancer patients who do more than the recommended weekly exercise had the best survival rates.
After five years, participants who exercised had a 12% incidence of cancer mortality compared to 16% in the non-exercisers, and the exercisers had a 2.4% incidence of death from other causes compared to 6.4% for the non-exercise group.
“Exercise consistent with national guidelines was associated with a reduction in cancer mortality and mortality from other causes of the entire follow-up period,” the researchers said.
“The benefit was observed within a few years after diagnosis and sustained for at least 20 years, but was not dose-dependent,” they said.
The study found that participants who exercised had a 25% reduced risk of dying from all causes within a 16-year average follow-up, compared to those who did not exercise.
Participants filled out questionnaires about the frequency, intensity and duration of their exercise habits.
They were considered to be meeting national exercise guidelines if they did moderate intensity exercise on four or more days of the week, with each session lasting at least 30 minutes, or if they did strenuous exercise on two or more days per week and each session lasted at least 20 minutes.
Thirty-eight per cent of participants could be defined as “exercisers”.
“Exercisers were more likely to be male, non-smokers, and had a lower prevalence of cardiovascular disease history (coronary heart disease or history of heart attack) than non-exercisers.”
The researchers also found that median survival from diagnosis was 19 years for exercisers and 14 years for the non-exercisers.
“The reduction in all-cause mortality in exercisers was apparent within five years, persisting for at least 20 years after diagnosis.”
The researchers said that compared with no exercise, exercising below guidelines gave a 25% reduction in all-cause mortality risk, meeting guidelines had a 35% reduction and those participants who exceeded guidelines had a 36% reduction.
Medical oncologist and professor of cancer medicine at the University of Sydney, Professor Janette Vardy, said it was a good study with a large cohort that included several tumour types.
The difference in mortality between the exercisers and non-exercisers was “impressive”, she said.
The study “surprisingly” showed improvement in head and neck cancer and renal cancer mortality in people who exercised, she said.
“Those are two cancers that hadn’t been looked at before and they’re not very common cancers.”
Studies about the benefits of exercise in cancer survival tend to focus on breast cancer, the authors noted. This study included diagnoses of breast, prostate, colon, hematopoietic, melanoma, bladder, lung, endometrial, renal, head and neck, ovarian, upper GI, pancreas, male breast, biliary, glioma and liver, and was the first to show benefits in head and neck and renal cancers.
Professor Vardy said more prospective studies and randomised controlled trials were needed to look at the tumour response to exercise for specific cancer sites.
Professor Vardy’s team is currently investigating the benefits of exercise in patients with early-stage colon cancer who have completed adjuvant chemotherapy. The randomised controlled trial will compare a personal trainer-guided three-year program with patients who were just told to exercise.
“That will give us sort of really important information with regard to whether or not there is a benefit for disease-free survival.”
Professor Vardy said previous data had shown that only 20-30% of cancer survivors meet the recommended exercise guidelines.
“I don’t think the guidelines need to change. I think what needs to change is how we help patients meet the guidelines.
“There’s no doubt that just telling people go and exercise isn’t sufficient.
“Even though there’s all this data coming out, including this study, saying that cancer patients should be exercising, we need to be facilitating how they do that.
“Even if they’ve been exercisers before, they sometimes don’t feel super comfortable in doing exercise after a cancer diagnosis.”
Professor Vardy said one of the key barriers for patients was a lack of facilities for patients to exercise.
Having exercise facilities within cancer centres, being able to get rebates through Medicare and healthcare funds, and more access to exercise physiologists trained in helping cancer patients would help patients exercise more after cancer, she said.
“In an exercise physiology course there might be a couple of lectures specific to cancer, yet one in two people are going to get cancer in their lifetime.
“Every exercise provider is going to come across people with cancer, but they could be better upskilled in how to best help them.”
One drawback of the study was that exercise was self-reported, she said.
“We know people overestimate that. What would be really nice, which wasn’t around with the earlier studies, is wearable devices. You’d get more of an accurate picture.”
Other limitations of the study were the self-selection bias of participants who are willing to answer an exercise questionnaire to begin with, and that patients had to be alive for a median of 4.5 years after a cancer diagnosis to be included in the study, she said.
“That’s taken out people with more aggressive tumours. To get far enough to get into the study they’ve got a better prognosis to start with.”
