Patient assessment of measures of bowel function during and after pelvic radiation therapy: An ancillary study of North Central Cancer Treatment Group study N00CA.

Abstract

e16572 Background: The Bowel Function Questionnaire (BFQ) has been used in clinical trials to document patient-reported symptoms following pelvic radiation therapy (RT). This study evaluated the importance patients placed on the symptoms included in the BFQ as measured by a Content Validity Questionnaire (CVQ). Methods: Patients treated with pelvic RT assessed symptoms and importance at baseline, after completion of RT (4 weeks), and 12 and 24 months. BFQ measured quality of life (QOL) and symptoms of: nocturnal bowel movements, incontinence, greater than one bowel movement in 30 minutes, need for protective clothing, inability to differentiate stool and gas, liquid bowel movements, urgency, cramping, and bleeding. Bowel movement frequency was also assessed. Symptoms were rated via the CVQ as “not very important,” “moderately unimportant,” “neutral,” “moderately important,” or “very important." Summary statistics were compiled. Fisher Exact, Chi-Square and Wilcoxon methodology compared BFQ and CVQ results. Results: 125 patients participated. All symptoms were rated as moderately important or very important by most patients.Measures of bowel function of greatest importance (moderately or very important) at baseline were ability to control bowel movements (94%), not having to wear protective clothing (90%), and not having rectal bleeding (93%). In general, patients gave similar ratings of symptom importance at all time points in the study and ratings were independent of whether the symptom was experienced. With the exception of the need for protective clothing, the presence of a symptom at 4 weeks was associated with significantly worse QOL (p-values < 0.001 to 0.005). Conclusions: The BFQ has excellent content validity. Patients rated most symptoms measured by the BFQ as moderately important or very important, indicating the BFQ is an appropriate tool for symptom assessment during and after pelvic RT. With the exception of the need for protective clothing, the presence of every symptom measured by the BFQ was associated with worse QOL. These criteria make them appropriate targets for future research to mitigate radiation-related bowel dysfunction.