Impaired quality of life (QOL) is commonly experienced by breast cancer survivors (BCS) due to direct effects of cancer or associated treatments. BCS are more predisposed to compromised QOL components in the physical, emotional, social, and cognitive well being domains than the general population. QOL may be affected by cardiorespiratory fitness (CRF); CRF refers to the ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during sustained physical activity. Higher levels of CRF, measured by maximal oxygen uptake (VO2max), are associated with higher QOL in healthy and diabetic populations, as improved CRF presumably eases activities of daily living and subsequently improves QOL. Limited research has examined the association between CRF and QOL in BCS. Purpose: The purpose of this study was to investigate the association between CRF, measured by estimated VO2max values (relative to body weight), and QOL, assessed by the FACT-B questionnaire, in BCS. Methods: Eligible participants (n = 45) were sedentary women diagnosed with stage I-III breast cancer, and who completed cancer-related treatments within 6 months prior to study enrollment in a larger ongoing exercise intervention trial. Baseline data were collected prior to initiating the exercise intervention. CRF was determined by estimated VO2max value (mL/kg/min) derived from the Single Stage Submaximal Treadmill Test, a 4-minute treadmill walking test where the treadmill speed is self-selected by the participant. Heart rate was obtained upon completion of the test and used to generate an estimated VO2max value using a validated equation. QOL was determined by the FACT-B questionnaire, a validated breast cancer specific questionnaire measuring four dimensions of QOL; physical well-being, social/family well-being, emotional well-being, and functional well-being. Each QOL dimension score was summed to yield an overall QOL score. The FACT-B questionnaire is scored out of a total 144 points from 0 (low QOL) to 144 (high QOL). A Spearman ranked-difference correlation test was used to determine the association between CRF and QOL. Independent t-tests were used to compare mean CRF and QOL between premenopausal and postmenopausal BCS. Results: Among BCS, mean estimated VO2max values were 29.13 ± 6.37 mL/kg/min, classified as average (45th percentile) according to the American College of Sports Medicine. Mean VO2max values for premenopausal BCS (n=24) was 31.01 ± 7.52 mL/kg/min and 27.22 ± 3.79 mL/kg/min for postmenopausal BCS (n=21); however these differences by menopausal status were not statistically significant (p>0.05). Mean FACT-B scores for BCS was 99.79 ± 21.02 (69th percentile). FACT-B mean scores for premenopausal BCS were 97.22 ± 21.23 (67th percentile) and 102.41 ± 21.75 (71st percentile) for postmenopausal BCS; however these differences by menopausal status were not statistically significant (p>0.05). Overall, there was a weak positive correlation between CRF and QOL (rs = 0.27, p<0.05). When stratified by menopausal status, we found a moderate positive correlation between CRF and QOL (rs = 0.48, p<0.05) in postmenopausal BCS. However, in premenopausal BCS, there was a weak non-significant correlation between CRF and QOL (rs = 0.36, p>0.05). Conclusion: In summary, QOL and CRF were weakly related, which differs from the stronger association between CRF and QOL in healthy and diabetic populations. However, this association between CRF and QOL was stronger in postmenopausal BCS, thus it may be valuable to further investigate the effect of menopausal status on CRF and QOL. Both CRF and QOL values were average and above average, respectively, in our sample which may explain the weak-moderate association between CRF and QOL. Nonetheless, due to the possible association between CRF and QOL, it may be necessary to consider investigating this association in a larger sample of BCS.
Citation Format: Christina M. Dieli-Conwright, Breanna Orozco, Joanne Mortimer, Debu Tripathy, Darcy Spicer, Leslie Bernstein. Association between cardiorespiratory fitness and quality of life in breast cancer survivors. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr B09.