Table 2.
Longitudinal associations between radiation dose (MHD and V5) and subsequent changes in GSLTPAQ scores and QoL metrics as measured by FACIT Fatigue or FACIT Dyspnea scales over time*
| Breast cancer, n = 80 | Lung cancer and lymphoma, n = 50 | ||||
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| RT dose volume exposure | Physical activity and QoL outcome measures | β-coefficient (95% CI)† | P value | β-coefficient (95% CI)† | P value |
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| MHD | GSLTPAQ score | 1.2 (−1.5 to 3.8) | .403 | −0.5 (−1.1 to 0.1) | .083 |
| GSLTPAQ MVPA score | 1.4 (−1.1 to 3.8) | .266 | −0.2 (−0.8 to 0.3) | .379 | |
| FACIT Fatigue score | −1.0 (−1.9 to −0.2) | .021 | −0.1 (−0.4 to 0.2) | .577 | |
| FACIT Dyspnea score | 0.1 (−0.6 to 0.7) | .888 | 0 (−0.1 to 0.1) | .954 | |
| V5 | GSLTPAQ score | 0.4 (−2.1 to 3.0) | .758 | −2.3 (−4.3 to −0.4) | .017 |
| GSLTPAQ MVPA score | 0.8 (−1.6 to 3.1) | .519 | −1.3 (−3.0 to 0.4) | .144 | |
| FACIT Fatigue score | −2.5 (−4.4 to −0.6) | .010 | −0.3 (−1.2 to 0.6) | .476 | |
| FACIT Dyspnea score | −0.5 (−2.1 to 1.0) | .507 | 0.1 (−0.3 to 0.5) | .725 | |
Abbreviations: CI = confidence interval; FACIT = Functional Assessment of Chronic Illness Therapy; GSLTPAQ = Godin—Shephard Leisure-Time Physical Activity Questionnaire; MHD = mean heart dose; MVPA = moderate-to-vigorous physical activity; QoL = quality of life; RT = radiation therapy; V5 = the percent volume of heart receiving 5 Gy.
Generalized estimating equation linear regression modeled the association between the change in each activity and QoL measure from baseline and heart radiation therapy dose exposure metrics. Models were adjusted for age, sex (for lung cancer and lymphoma only), chemotherapy exposure (none, preceding, or concurrent), RT duration, time point of assessment, and baseline GSLTPAQ or FACIT score. Note that higher overall GSLTPAQ scores indicate greater physical activity, higher FACIT fatigue scores indicate less fatigue, and higher FACIT dyspnea scores indicate worse dyspnea.
β-coefficients represent the difference in the change from baseline at each post-RT time point for a given physical activity or QoL outcome measure for every 1-Gy increase in MHD or for each 10% increase in V5.