Cancer therapy may impair cardiorespiratory fitness for years after treatment
Key takeaways:
- Cancer therapy may reduce cardiorespiratory fitness, as measured by peak VO2, for years after treatment.
- Exercise therapy may benefit patients undergoing cancer therapy.
Cancer treatment, primarily chemotherapy, is associated with impaired cardiorespiratory fitness years after treatment has ended and regardless of cancer subtype, according to a meta-analysis published in JACC: CardioOncology.
“Cardiorespiratory fitness, measured by peak oxygen consumption (VO2 peak), provides an objective indicator of overall cardiovascular capacity. In patients with cancer, low VO2 peak is associated with a higher symptom burden and an increased prevalence of long-term treatment-related cardiovascular disease risk factors and is a strong, independent predictor of cancer, cardiovascular and all-cause mortality,” Sara H. Johansen, MSC, of the department of physical performance at Norwegian School of Sport Sciences in Oslo, Norway, and colleagues wrote. “The aim of this systematic review and meta-analysis was to evaluate the effects of systemic anticancer treatment on VO2 peak in adults with cancer.”
The systematic review and meta-analysis incorporated 44 studies, of which 27 were prospective trials including 1,234 cancer survivors (median age, 52 years) and 17 were cross-sectional studies including 1,372 cancer survivors (median age, 54 years) and 1,923 controls without cancer (median age, 56 years).
The primary endpoint was the change in cardiorespiratory fitness as measured by change in peak VO2 before and after systemic anticancer treatment. Secondary endpoints included posttreatment differences in peak VO2 between cancer survivors and controls without cancer in addition to physiological determinants of peak VO2.
Overall, 91% of the studies focused on cancer treatment with chemotherapy.
In the prospective trials, the median cancer treatment duration was 13 weeks; however, nearly one-third of trials did not report treatment duration.
Systemic anticancer treatment was associated with an average decrease in peak VO2 of 2.13 mL/kg1/min1 from before to after treatment (95% CI, 2.76 to 1.5), and there were no significant differences reported based on cancer type, according to the study.
During a median follow-up of 2 years after completion of cancer therapy, researchers reported peak VO2 was on average lower among patients treated for cancer compared with controls without cancer (weighted mean difference, 6.39 mL/kg1/min1; 95% CI, 7.6 to 5.18).
Among various physiological determinants of peak VO2, reduced arteriovenous oxygen difference was associated with reduced peak VO2 (beta = 2.55; 95% CI, 2.05-3.06; P < .001) and the researchers reported no significant association between cardiac output and peak VO2 (beta = 0.88; 95% CI, 1.95 to 0.18; P = .1).
“This is the first study to extensively characterize the magnitude of systemic therapy-related impairments across various cancer settings,” the researchers wrote. “Given the established association between impaired VO2 peak and adverse clinical outcomes in cancer patients, these findings support the recommendation for exercise therapy aimed at preserving and improving VO2 peak during and following cancer treatment.”
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