Risk Factors for Septic Shock After Irinotecan-Containing Chemotherapy: An Exploratory Case-Control Study.

Background and objectives: Irinotecan sometimes causes lethal septic shock but the risk factors remain unclear. This retrospective case-control study explored the potential risk factors for septic shock following irinotecan treatment.

Methods: All women who received irinotecan-containing chemotherapy for gynecologic malignancies at Shizuoka General Hospital from October 2014 to September 2020 were investigated. The clinical backgrounds and blood test results of those who developed septic shock after irinotecan-containing chemotherapy were compared with those who did not. Odds ratios (ORs) for developing septic shock after receiving irinotecan were calculated with 95% confidence intervals (CIs), using univariable logistic regression analysis.

Results: During the study period, 147 women received irinotecan-containing chemotherapy. Three women developed septic shock due to neutropenic enterocolitis after irinotecan treatment, and 144 did not. The three patients with septic shock had recurrent cervical cancer, heterozygous variants in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene (two patients had *1/*6, one had *1/*28 variants), a history of concurrent chemoradiation therapy, 50-60 Gy of pelvic irradiation, and platinum-combined chemotherapy. A history of pelvic irradiation was identified as a possible risk factor for developing septic shock after irinotecan-containing chemotherapy (OR 63.0, 95% CI 5.71-8635; p < 0.001). The OR of UGT1A1 polymorphism for septic shock was 9.09 (95% CI 0.86-1233; p = 0.070) in the complete case analysis.

Conclusion: Medical personnel involved in cancer therapy should consider the possible risk of septic shock developing due to neutropenic enterocolitis when administering irinotecan-containing chemotherapy in patients with a history of pelvic irradiation.