Risk and outcomes of chemotherapy-induced diarrhea (CID) among patients with colorectal cancer receiving multi-cycle chemotherapy

Diarrhea is a common toxicity of chemotherapy, but the practice of reporting only severe grades (a parts per thousand yen 3) in clinical trials results in misleading conclusions of significance. Epidemiology remains poorly described, and effects of multi-cycle regimens have not been investigated. To better understand the risks, symptom burden and consequences of CID, we studied patients receiving chemotherapy for colorectal cancer (CRC). One hundred and fourteen patients receiving FOLFOX (95 patients, 530 cycles), FOLFOX + monoclonal antibodies (10 patients, 49 cycles) or FOLFIRI (9 patients, 50 cycles) were enrolled. CID was identified from diaries at baseline and daily during up to 8 chemotherapy cycles using supplemental questions on the Oral Mucositis Daily Questionnaire, a valid tool for collecting patient-reported outcomes of regimen-related mucosal injury. Patients scored CID severity from 0 "none" to 10 "worst possible," and quantity from "little" to "severe" on a 5-point scale. Quality of life was measured using the FACT-G, and fatigue using the FACIT fatigue scale. CID occurred in 89 % of patients on FOLFIRI, 50 % on FOLFOX + monoclonal antibodies and 56 % on FOLFOX alone. The risk of a first episode was highest during Cycle 1 (35 %) and dropped to < 10 % during Cycles 3-5. Patients with CID reported poorer quality of life scores than those without CID (77.1 vs 80.7). Diarrhea occurs more commonly than typically appreciated during chemotherapy for CRC. Risk is highest during first exposure, suggesting variable susceptibility. Identification of this high-risk subgroup for prophylaxis could improve the quality of life.