Early clinical outcomes and long-term survival in MM patients undergoing autologous HSCT after Melphalan 200 mg/m2 conditioning without weight-based dose-adjustment are unaffected by body mass index

Introduction: Autologous hematopoietic stem cell transplantation (aHSCT) with high-dose melphalan (Mel 200 mg/m2) conditioning regimen, in multiple myeloma (MM), is associated with high morbidity, particularly oral and gastrointestinal (GI) mucositis. Dose-adjustment to avoid toxicity in obese patients (PTS) is controversial: while some studies suggest that doses should be adjusted, we have previously demonstrated that body mass index (BMI) does not worsen the major clinical outcomes of aHSCT. Patients and Methods:We analyzed all 143 consecutive aHSCT performed for MM in our center between 2008 and 2014; 9 PTS were excluded (3 due to dose-reduction related to comorbidities and 6 due to missing data). Results: The mean age was 57.0 8.9 years, with 56.2% of males; the most common subtype was IgG (51.1%). The mean BMI at admission was 27.0 3.4 kg/m2; no PTS were underweight, 30.7% were of normal weight, 51.1% were overweight and 18.2% were obese. There were no differences in the incidence of nausea (Ns), vomiting (Vt), diarrhea (Dh) or odynophagia (Od) in the three weight classes (WC) (p1⁄4NS); the mean dose of Mel in PTS with or without Ns, Dh or Od, or by the grade (CTCAE v4.0) of GI or oral toxicity, was identical (p1⁄4NS); unexpectedly, PTS with Vt had received a lower mean dose of Mel (337 4.2 vs 352 4.3, p1⁄40.016).