Analysis of causal models of diet for patients with head and neck cancer receiving radiation therapy.

PURPOSE This study seeks to establish causal models of diet which maintain the appetite of head and neck cancer patients receiving radiation therapy. SAMPLE AND METHODS We collected data from 208 patients at two radiation doses, 30/50 Gy, using a questionnaire on appetite and analyzed the items using structural equation modeling. RESULTS In the causal model for 30 Gy, we established a path using the four intervening variables "ease of consuming foods in smooth forms," "ease of consuming foods with a chewable texture and suitable temperature," "ease of consuming lightly seasoned foods with a flavorful smell," and "overall ease of consuming a given meal" from the temporal relationship between "dietary preferences" and "maintaining appetite while caring for the oral cavity." In the causal model for 50 Gy, we established a path between "ease of consuming foods with a mild temperature and smell," and "maintaining appetite while caring for the oral cavity" using the four intervening variables "ease of consuming foods that are easy to swallow," "ease of consuming foods that dissolve well in the mouth," "ease of consuming foods with a mild taste," and "overall ease of consuming a given meal." The goodness of fit indices for both models were above 0.85 for both the goodness of fit index (GFI) and adjusted GFI (AGFI), and less than 0.08 for root mean square error of approximation (RMSEA), indicating a satisfactory goodness of fit. CONCLUSIONS Food characteristics help to maintain patient appetite at cumulative radiation doses of 30/50 Gy.