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Exercise consistent with national guidelines was associated with a significant reduction in all-cause mortality in long-term cancer survivors, a pan-cancer analysis showed.

In a study involving 11,480 survivors, guideline-concordant exercise was associated with a 25% reduced risk of all-cause mortality compared with no exercise (HR 0.75, 95% CI 0.70-0.80) at a median follow-up of 16 years from diagnosis, reported Lee W. Jones, PhD, of Memorial Sloan Kettering Cancer Center in New York City, and colleagues.

In addition, exercise consistent with national guidelines was associated with a significant reduction in cancer mortality (HR 0.79, 95% CI 0.72-0.88), as well as mortality from other causes (HR 0.72, 95% CI 0.66-0.78).

"Our findings show exercise is a holistic strategy that may complement contemporary management approaches to further reduce cancer mortality (in select sites) while simultaneously lowering risk of death from other competing causes, which combine to improve ACM [all-cause mortality]," Jones and team wrote in the .

Meeting national guidelines was defined as engaging in moderate-intensity exercise ≥4 days per week, with each session averaging ≥30 minutes in duration, and/or strenuous-intensity exercise ≥2 days per week, with each session averaging ≥20 minutes in duration. Not meeting the guidelines was defined as engaging in exercise below the criteria for meeting national guidelines, including 0 days of exercise per week.

Over the study period, 1,459 total deaths occurred among the 4,374 participants classified as exercisers (33%), while there were 3,206 deaths among the 7,106 classified as non-exercisers (45%). Median overall survival from diagnosis was 19 years for exercisers and 14 years for non-exercisers.

The 5-year cumulative incidence of cancer mortality was 12% for exercisers compared with 16% for non-exercisers, and the 5-year cumulative incidence for death from other causes was 2.4% and 6.4%, respectively.

"Exercise is medicine, and these results support this," said Stacey A. Kenfield, SM, ScD, and June M. Chan, ScD, both of the University of California San Francisco, in an . They called the difference in mortality between the groups "striking," adding that it "underscores that exercise (in addition to standard therapies) is one of the best daily pills cancer survivors can take to optimize their longevity."

Jones and colleagues also observed that exercise dose was associated with cancer mortality, with a reduced risk among survivors who met and exceeded guidelines (25% and 33%, respectively), and even among those exercising below those guidelines (19%), compared with non-exercisers.

Regarding specific cancer sites, exercise was associated with a reduction in the hazard for all-cause mortality for patients with breast, endometrial, head and neck, hematopoietic, prostate, and renal cancers, with those reduced risks ranging from 22% (HR 0.78, 95% CI 0.70-0.86) for prostate cancer to 59% (HR 0.41, 95% CI 0.24-0.72) for endometrial cancer.

Exercise was also associated with a reduction in cancer mortality for those with head and neck cancer (HR 0.49, 95% CI 0.25-0.96) and renal cancer (HR 0.34, 95% CI 0.15-0.75).

The study included participants enrolled in the from November 1993 to July 2001 who had a confirmed diagnosis of cancer and provided exercise data via a standardized survey quantifying exercise after diagnosis. The median interval between cancer diagnosis and completion of the exercise questionnaire was 4.5 years.

Among participants, 62% were defined as non-exercisers, while the remaining 38% were defined as exercisers. Overall, the estimated median time spent on moderate and strenuous exercise per week was 44 minutes and 19 minutes, respectively.

Kenfield and Chan noted that these figures reinforce "the continued need for patient education at the time of diagnosis and referral to exercise oncology support to increase moderate to vigorous exercise levels."

Of the 4,665 documented deaths, 1,940 were due to cancer and 2,725 were due to other causes.

The most common cancer diagnoses observed during follow-up were prostate cancer (37%), followed by breast cancer (20%).

Study limitations included that assessments of exercise were self-reported, which means misclassification of exercise exposure was likely. Furthermore, the population sample was largely white, with a distribution of cancer sites not representative of the general population, "which introduces selection bias," Jones and team noted.

They also pointed out that it is not possible to determine whether exercise reflects lower disease and/or treatment-related toxicities, rather than exercise-induced effects or better adherence to a healthier lifestyle. The only way to definitely prove causality is through randomized trials, they added.

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