When People with Cancer Exercise, They May Have Less Pain
Data from the ACS CPS-II Nutrition Cohort showed that using physical activity to manage pain is as effective for people with cancer as for people without it.
The Challenge
People with cancer often have ongoing pain.
The evidence that physical activity reduces pain is so strong for people without cancer that exercise is considered a key part of pain management. Physical activity has been shown to reduce physical pain. Exercise may also help decrease depression and fatigue, which in turn lowers the risk for developing pain.
But there hasn’t been much research to answer the question: Can physical activity help ease pain for people during and after cancer treatment?
The answer could be transformative for the quality of life for people with cancer because pain affects 55% of people being treated for cancer and 40% after the end of cancer treatment.
That pain can be caused by cancer itself, tumors that have spread (metastases), or by the treatment, including surgery, chemotherapy, radiotherapy, or hormone therapy. Pain can also be an on-going, unwelcome reminder of the cancer experience or about why treatment had to be stopped.
Finding ways to ease pain that don’t include medications—what people with cancer say they prefer—could help improve the lives of many people with cancer.
The Research
Before the publication of of “Physical Activity and Pain in People with and without Cancer,” in the American Cancer Society (ACS) peer-reviewed journal, Cancer, research about how well physical activity helped ease pain in people with cancer was limited to small sample sizes and mostly focused on only one type of cancer.
This study, written by 2 Australian and 3 ACS researchers, used data from ACS Cancer Prevention Study-II (CPS-II) Nutrition Cohort, a large substudy that examines lifestyle factors, cancer risk, and mortality. The researchers analyzed physical activity and pain data from the responses participants gave to the 2009 lifestyle and medical survey, the first year when both measurements were collected. They followed up on the measurements with the next survey in 2011. Participants included 10,651 people with a history of cancer and 51,439 people without it.
Here's an overview of their key findings:
People with or without cancer who met or exceeded physical activity guidelines between the 2 years studied (2009 to 2011) reported much less pain (lower intensity) compared to those who reported remaining physically inactive for those 2 years.
Being active even some of the time helps more than being inactive all of the time.
- Physical activity was associated with less pain for people who were inactive at the start of the time studied but were exercising 2 years later (2009 to 2011). This is promising because it shows starting to exercise after cancer is beneficial and that being active even some of the time may reduce pain more than being inactive all of the time.
- Physical activity was associated with less pain for people who started out active in 2009 but had become inactive in 2011. “This may suggest that the benefit of physical activity for pain intensity can be maintained even after a period of inactivity,” the authors wrote.
Pain relief from exercise helped some people more than others.
- The benefit of exercise was larger in women compared to men. The authors wrote, “This finding may also represent factors such as sex or gender differences in the willingness to report pain,” and it may identify a potential difference in the response males and females have to analgesics.
- The benefit of exercise was larger for people with breast cancer or a type of blood cancer than it was for people with colorectal, lung, and prostate cancer.
There was no relationship between physical activity and analgesic use.
- The study authors said this was unexpected because it seems reasonable that as pain decreased, so would analgesic use.
- They hypothesized that:
- Exercise may not improve pain intensity enough to noticeably change analgesic use.
- The measurement used—how many times a month participants took an analgesic—was not sensitive enough to capture the nuance in pain medication use.
The ACS researchers who participated in this study were: Matthew Masters, MPH, Alpa Patel, PhD, MPH, and Erika Rees-Punia, PhD, MPH.
Why It Matters
This study makes an important and new contribution to cancer pain literature by showing that the associations of physical activity and pain are not dissimilar between cancer survivors and people with no history of cancer with a large group of people. Identifying new ways to reduce pain is especially important for older adults, like those who made up a large portion of the CPS-II Nutrition Cohort, because that population is more likely to develop and report severe pain than younger adults.
Future studies could expand knowledge by asking participants about the types of pain they experienced; whether they were taking codeine or other opioids; and about treatments that weren't commonly used in 2009 or 2011 but are widely used now, such as immunotherapy and target therapies. They could also focus more about the potential of reverse causation that greater pain results in people who are less physically active.
