Incidence and Outcomes of Neutropenic Enterocolitis Post-stem Cell Transplant for Hematological Malignancies: A Retrospective Study in Australia.

Neutropenic enterocolitis (NE) is a well-known occurrence in patients who receive chemotherapy and stem cell transplantation for hematological malignancies. Nonetheless, there is a lack of Australian research data available on this life-threatening condition. The purpose of this study is to determine the percentage of patients with multiple myeloma and lymphoma who develop NE after autologous stem cell transplant (ASCT) in an Australian setting and to examine the mortality rates in the selected group. Retrospective data were collected from a small pilot group of patients (N = 33) at a private hospital in Melbourne, Australia, who underwent ASCT between February 2023 and December 2024 for multiple myeloma and lymphoma. Patients received either carmustine, etoposide, cytarabine, and melphalan (BEAM); melphalan; or thiotepa, busulfan, and cyclophosphamide (TBC) as conditioning chemotherapy. Patients were then transplanted with peripherally collected CD34+ (positive) cells. Results indicate that 100% of the patient population developed neutropenia, characterized by an absolute neutrophil count (ANC) of 0.0 × 10⁹/L and gastrointestinal (GI) symptoms, including diarrhea. Patients who received the BEAM conditioning regimen developed absolute neutropenia earlier than those who received different conditioning regimens. Twenty (60%) patients developed neutropenic infections confirmed by positive microbiology results. , ,  (), and Norovirus were the main causative organisms for neutropenic infections in the study population. Thirty-one (94%) patients were treated with broad-spectrum antibiotics. A positive correlation was found between the onset of absolute neutropenia and the onset of GI symptoms. Ten patients (30.3%) had radiographic evidence confirming NE. The incidence of NE in this study is higher (30.3%) than in previous findings (9%) published in the United States, while the mortality rate remains low (6%). The low mortality rates are likely attributed to close monitoring, early screening, intensive care unit (ICU) management, and the aggressive use of broad-spectrum antibiotics. All patients were managed conservatively without needing surgical intervention. It was also identified that there is a need for standardized criteria for the diagnosis of NE based on clinical presentation, rather than the current guidelines, which include neutropenia with a neutrophil count of <0.5 × 10⁹/L, fever, abdominal pain or diarrhea, and the need for a radiographic evidence of bowel wall thickening >4mm for confirmation of the diagnosis of NE. The reliance on international literature on this topic, combined with the scarcity of Australian-specific studies, underscores the importance of this study and its findings. The low mortality rates found in this study are promising for patients undergoing ASCT for hematological malignancies.