BACKGROUND: While neutropenic enterocolitis (NEC) is a well-known life-threatening complication during intensive chemotherapy, its incidence, impact and outcome on specific at-risk populations remain ill-defined. METHODS: We report 178 NEC episodes during 1963 myeloablative chemotherapy courses among 1259 adult patients with acute myeloid (AML) or lymphoid (ALL) leukemia or receiving autologous hematopoietic stem cell-transplant (auto-HCT) for lymphoma or multiple myeloma. Risk factors were assessed by multivariate logistic regression models. RESULTS: Most NEC cases (93.3%) occurred during AML induction (N=92, 13.8% of chemotherapy course) and auto-HCT (N=74, 9.5%). Independent risk factors for NEC during AML induction included high-dose corticosteroids (OR=2.07, 95%CI 1.29-3.30, P=0.002), elevated circulating blasts at the time of diagnosis (>
50 G/L, OR=2.02, 95%CI 1.15-3.56, P=0.02) and use of azacitidine (OR=2.45, 95%CI 1.01-5.90, P=0.05)
purine-based regimens (e.g. FLAG-Ida) was an independent protective factor (OR=0.27, 95%CI 0.15-0.47, P<
0.001). Independent risk factors after auto-HCT included BEAM versus another conditioning protocol (OR=3.28
95%CI 1.98-5.43, P<
0.001) and age (OR=1.03 per year, 95%CI 1.01-1.06, P=0.007). For both AML induction and auto-HCT, NEC was associated with longer hospitalization (P=0.03 and P<
0.001), sepsis (quick SOFA≥2, P=0.03 and P<
0.001), fungemia (P<
0.001 and P=0.01) and intensive care admission (P=0.03 and P<
0.001, respectively). NEC was associated with increased in-hospital mortality during AML induction (6.5% versus 2.4%, P=0.04) but not during auto-HCT (P=0.3). CONCLUSIONS: The incidence of NEC depended on chemotherapeutic regimens, with higher occurrence during standard "7+3" AML induction and BEAM conditioning for auto-HCT. NEC was associated with longer hospitalization and increased morbidity, but 30-day mortality was lower than previously reported.