ABSTRACT
Purpose: To assess any correlation between swallowing dysfunction and radiation dose to 5 subregions of the larynx. Methods and Materials: A cohort of 136 patients with head and neck cancer, treated with either photon or proton radiation therapy, was assessed using an endpoint of patient-reported swallowing scores, evaluated with the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire-H&N35 survey, within 1 month after treatment. Five subregions of the larynx were contoured, and dosimetric metrics were extracted for each subregion as well as the total larynx. Univariate and multivariate logistic regression statistical analyses were used to determine statistical correlation with the dose metrics and clinical variables. Univariate regression models were statistically compared using a non-nested model test. Results: Under univariate analysis, unilateral versus bilateral nodal irradiation (P = .004), concurrent chemotherapy (P = .007), and surgery (P = .015) were statistically significant predictors of poor swallowing score. Unilateral versus bilateral irradiation was statistically significant under multivariate analysis (P = .039). The epiglottis was the most predictive subregion of swallowing score, with a majority (21 of 25) of dosimetric variables being identified as statistically significant. The maximum dose to the epiglottis was the most significant dosimetric variable tested for poor swallowing score in both univariate (P = .003) and multivariate (P = .051) analyses. Comparison of univariate models indicated a general preference for epiglottic variables with the mean dose to the epiglottis being preferred at a statistically significant level in many cases. Conclusions: These results show the relatively increased sensitivity of the epiglottis compared with the rest of the larynx when considering patient-reported decrements in quality-of-life swallowing score and support both the inclusion of the epiglottis in standard larynx contours and the assessment of the epiglottis dose during plan evaluation. Our data suggest that keeping the mean and max doses to the epiglottis <20 to 37 Gy and <53 to 60 Gy, respectively, will reduce swallowing difficulties.
ABSTRACT
PURPOSE: Being overweight/obese, having hypertension, and being postmenopausal are risk factors for the development of congestive heart failure (CHF). A characteristic of CHF is an abnormal V(E)/VCO(2) slope, which is predictive of mortality in patients with CHF. Although the V(E)/VCO(2) slope is well established in CHF patients, little is known regarding interventions for "at-risk" populations. METHODS: We examined the V(E)/VCO(2) slope in 401 sedentary, overweight, moderately hypertensive women randomized to 6 m of nonexercise (control) or 4 kcal x kg(-1) x wk(-1) (KKW), 8 KKW, or 12 KKW of exercise at an intensity corresponding to 50% of baseline VO(2max). We examined trends in exercise treatment dose versus change in mean V(E)/VCO(2) slope using a linear regression model (KKW vs V(E)/VCO(2) slope) and a linear mixed model. RESULTS: Regression analysis showed a significant trend for a reduction in the V(E)/VCO(2) slope from baseline (mean +/- SD: 32.6 +/- 6.3; P < 0.004). When expressed as mean change (95% confidence interval (CI)) from baseline, we observed significant reductions in the V(E)/VCO(2) slope for the 8-KKW (-1.14; 95% CI, -1.5 to -0.2) and 12-KKW (-1.67; 95% CI, -2.3 to -0.3) groups. No significant effect was noted for the 4-KKW (-0.4; 95% CI, -1.2 to 0.15) group. CONCLUSION: Moderate-intensity aerobic exercise at doses of 8 KKW or greater seems to present an adequate dose of exercise to promote small but significant reductions in the V(E)/VCO(2) slope in postmenopausal women who exhibit risk factors associated with the development of CHF.
