Balke-Ware Vo2peak Prediction Equations Are Inaccurate For Cancer Survivors

Abstract

INTRO: Cancer and its treatments may cause cardiotoxicities such as cardiomyopathy, EKG abnormalities, lower left ejection fractions, reduced cardiac output, and decreased blood perfusion in tissues. Physical abatements related to cancer and its treatments can be reduced with an individualized exercise prescription. Proper cardiovascular testing is crucial for an exercise prescription and can result in improved VO2Peak (VO2P) as a measure of cardiovascular health and overall quality of life. Currently, a cancer-specific protocol (CANCER) is the only validated treadmill protocol for cancer survivors. Despite this, the Balke-Ware (BW) protocol is often used in clinical settings but it has only been validated for apparently healthy individuals. It is unknown if the BW is appropriate for cancer survivors. PURPOSE: To determine if (1) measured VO2P from BW and CANCER protocols differ and (2) if predictive VO2P equations for the BW are accurate for testing cardiovascular fitness in cancer survivors. METHODS: Thirty-four subjects participated in the study. Subjects completed the CANCER and BW protocols one week apart in randomized order. Measured VO2P was obtained from gas analysis using a research grade metabolic cart. Predicted VO2P was calculated using BW prediction equations from the completed BW gas analysis test. A paired samples t-test was used to test for significance (p < 0.05) for both comparisons. RESULTS: All subjects completed the CANCER protocol, but one subject could not complete the BW. No significant differences were found in VO2P values (mL·kg-1 ·min-1) between CANCER (28.1 ± 0.65) and BW (26.3 ± 0.76) (p = 0.192). Significant differences were found between predicted and actual VO2P from the BW protocol (19.7 ± 1.33 vs. 26.3 ± 0.76, respectively) (p < 0.001). CONCLUSION: Data indicates if direct gas analysis is available, BW appropriately determines VO2P in cancer survivors. However, if direct gas analysis is unavailable, BW predictive VO2P equations significantly underestimate VO2P in cancer survivors. The CANCER protocol provides accurate VO2P values with or without a metabolic cart. Therefore, in a clinical setting where using direct gas analysis may not be practical, the CANCER protocol remains the current gold standard for assessing cardiovascular fitness in cancer survivors.