Correlation Between Dose-Volume Parameters and Patient-reported Quality of Life (QOL) During Image-guided Intensity Modulated Radiation Therapy (IGRT) for Prostate Cancer

Abstract

There is increasing recognition of the importance of patient-reported QOL as an outcome in cancer treatment. However, to date, limited research has examined the relationship between radiation dose-volume parameters and patient-reported acute genitourinary (GU) and gastrointestinal (GI) symptom development during IGRT for prostate cancer. We analyzed the relationship between dose-volume parameters of the rectum and bladder with prospectively collected patient-reported QOL. One hundred four men with prostate cancer who received radiation therapy to a median 75 Gy at our institution from 2010 to 2012 were included. Weekly during treatment, patients completed a validated questionnaire assessing severity of GI (diarrhea, urgency, bleeding, pain, cramping, mucus, and tenesmus) and GU (ease of flow, dysuria, nocturia, frequency, urgency, and incontinence) symptoms on a 4 or 5-point Likert scale. The association between dose-volume parameters and maximum GI and GU symptom scores was examined using Spearman's correlation. Median age was 64 years, and 72% of patients had clinical T1c or T2a disease. The percent volume of bladder receiving at least 75 Gy and 80 Gy was significantly associated with overall GU symptom score (V75: correlation coefficient .27, p = 0.005; V80: coefficient .30, p = 0.001). GI symptom score was significantly associated with V60 (coefficient .22, p = 0.03) and V65 (coefficient .26, p = 0.007) of the rectum. The proportions of bladder and rectum receiving higher doses of radiation were significantly associated with patient-reported acute GU and GI symptoms during IGRT for prostate cancer. A better understanding of the relationship between dose-volume parameters to surrounding organs and patient-reported QOL may allow physicians to improve radiation planning to optimize patient outcomes.