Patient-Reported Bowel and Urinary Function in Long-Term Survivors of Squamous Cell Carcinoma of the Anus Treated With Definitive Intensity Modulated Radiation Therapy And Concurrent Chemotherapy

Purpose: Definitive radiation therapy with concurrent chemotherapy is curative for nonmetastatic squamous cell carcinoma of the anus (SCCA). However, the true effect of chemoradiation on long-term functional outcomes is poorly understood owing to limited follow-up and patient-reported outcomes (PROs). Methods and Materials: We conducted a cross-sectional survey of 248 patients with SCCA treated with definitive intensity modulated radiation and concurrent chemotherapy from 2010 to 2018 who were alive and without recurrence. PRO measures were collected, including Functional Assessment of Cancer Therapy-General (FACT-G7), Fecal Incontinence Quality of Life (FIQoL), Low Anterior Resection Syndrome (LARS), and International Consultation on Incontinence Questionnaires (ICIQ). Models were used to determine the association between demographic, tumor, treatment, and dosimetric data with PROs. Results: One hundred twelve (45%) patients completed PROs. Median [interquartile range (IQR)] time from radiation completion to survey was 51 [37-85] months. The median scores [IQR] for FACT-G7, FIQoL, and LARS were 21 [15-24], 14 [11-16], and 32 [25-37], respectively. For men, median subscores [IQR] for ICIQ voiding and incontinence subscores were 5 [2-6] and 1 [1-3], respectively. For women, median subscores [IQR] for ICIQ voiding, incontinence, and filling were 1 [1-3], 5 [3-8], and 4 [2-5], respectively. Higher (better) FIQoL scores were associated with higher (better) FACT-G7 scores (β = 0.83; 95% confidence interval, 0.58-1.09; P <.001), and higher (worse) LARS scores were associated with lower (worse) FACT-G7 scores (β = –0.22; 95% confidence interval, –0.31 to –0.13; P <.001). A separate multivariable analysis revealed higher bowel bag D1% was associated with lower (worse) FIQoL (P =.001) and higher (worse) LARS (P =.003) scores. Higher bladder V40 Gy was associated with increased (worse) ICIQ voiding subscore (P =.001). Conclusions: Patients treated with modern chemoradiation for SCCA experience significant long-term bowel toxic effects with considerable effect on quality of life. Minimizing bowel hotspots and bladder V40 Gy may improve bowel and urinary function. Other interventions to reduce long-term toxic effects and improve quality of life are needed.