A. Burnette1, D. Laskowitz2, S. Felder1,2, S. Dessureault1,2, B. Powers1,2, S. Dineen1,2 1University Of South Florida College Of Medicine,Tampa, FL, USA 2Moffitt Cancer Center And Research Institute,Tampa, FL, USA
Introduction:
Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is a treatment strategy for patients with peritoneal dissemination of disease from appendiceal or colorectal primary cancers. Mitomycin C (MMC) is the most common chemotherapeutic agent used for chemoperfusion in the United States. Side effects of CRS-HIPEC with MMC include neutropenia. We previously demonstrated a high incidence of neutropenia at our institution, leading to a change in our practice from weight based dosing of MMC to a fixed dosing protocol. We hypothesized this would reduce the incidence of neutropenia.
Methods:
Prior to Jan 1st, 2018 MMC was dosed according to a weight based protocol (17.5 mg/m2 followed by 2 additional doses of 8.8mg/m2 at 30 and 60 minutes into the perfusion). Following this date, we changed to a 40mg fixed dose of MMC, 30mg at initiation of HIPEC followed by an additional 10 mg after 60 minutes. We identified 49 patients treated with the fixed dose regimen and compared this cohort to a previously assessed wt-based dosing cohort. Neutropenia was defined as an absolute neutrophil count (ANC) of less than 1.5 k/uL or a white blood cell count of less than 2 k/uL with the use of granulocyte colony-stimulating factor. Chi-square and Kruskal-Wallis tests were used to assess differences between groups. Overall survival was assessed with Kaplan-Meier method.
Results:
49 patients who underwent CRS-HIPEC with MMC were identified between 1/1/2018 and 5/31/2019. Appendiceal pathology represented 75% of patients, colon cancer 14.3% and other primary pathology 10.2%. The median age was 55.5 years. Two patients demonstrated neutropenia in the fixed dosing cohort. Compared to patients treated with a weight-based dosing, the incidence of splenectomy was higher. Age, body mass index, median PCI, and incidence of complete cytoreduction were not different between the two cohorts. Neutropenia rates were significantly reduced (27.9% vs 4.1%, p < 0.001) in the fixed dose cohort.
Conclusion:
The incidence of neutropenia following CRS-HIPEC with MMC was significantly reduced using a fixed dose of 40mg compared to the previous weight-based dosing regimen. With regard to the prevention of neutropenia, we recommend the fixed dosing scheduled. However, longer follow up is required to compare recurrence and survival rates.