Outcomes of Autologous Hematopoietic Stem Cell Transplantation Depending on Body-Mass Index in Patients with Multiple Myeloma
Authors: Firsova Maiia V. , Mendeleeva Larisa P. , Solovev Maxim V. , Savchenko Valery G. 
Published: November 2019

Introduction. About ten years ago, the International Agency for Research on Cancer corroborated the association of obesity with the risk of cancers of the gastrointestinal tract, breast, endometrium and kidney. In a report published in 2016, eight cancer types were added in this list, including multiple myeloma (MM).
Aim of the study. To study the impact of obesity on the efficacy of autologous hematopoietic stem cell transplantation (auto-HSCT) in MM patients.
Materials and methods. 99 MM patients (37 males, 62 females), aged from 27 to 66 years (median 54) underwent auto-HSCT in 2016-2017 were enrolled in the study. The diagnosis was made according to IMWG criteria (2014). Induction therapy included bortezomib-containing regimens in all patients (first-line therapy), immunomodulatory drugs were used in 21 % of the patients (second-line therapy). Before auto-HSCT complete response (CR) was documented in 49% of the patients, very good partial response (VGPR) was achieved in 51% of the patients. After induction chemotherapy, patients received melphalan 200 mg/m2 (95% of the patients) and melphalan140 mg/m2 (5% of the patients with dialysis-dependent renal failure) before undergoing auto-HSCT. A standardized body-mass index (BMI) was calculated before performing the transplantation. The median follow-up period since the auto-HSCT was 22 months. Progression-free survival (PFS) was assessed for a period of 3 years after autologous HSCT. Survival curves were constructed using the Kaplan-Meier method. Statistical analysis was done using Statistica 10.
Results. A normal body weight (a BMI &lt;25 kg/m2) was documented in 22% of the patients, an overweight status (a BMI between 25 and 29, 9 kg/m2) was established in 53% of the patients. Obesity (a BMI &gt; 30 kg/m2) was diagnosed in 25% of the MM patients. When analyzing the PFS, it was revealed significant differences depending on the body-mass index of the patients. Thus, in patients with a normal BMI the 3-year PFS rates was significantly higher (Cox's F-test, p&lt;0,05) and was 69% versus 45% and 33% in the group of patients with overweight or obese, respectively (fig.1).
Conclusion. Obesity has reached epidemic proportions globally. It is important to identify the factors that raise the risk of MM progression. Our study confirmed the hypothesis of the negative impact of obesity on the results of the treatment of MM patients. All patients achieved a good response - CR or VGPR before auto-HSCT. The analysis of the 3-year PFS rates demonstrated, that the results of autologous HSCT in MM patients suffering from obesity was significantly worse than the same results in patients with normal body weight (3-year PFS 33% vs. 69%, p&lt;0,05). Obesity is a modifiable risk factor; shifting a patient's behaviour after diagnosis could reduce their risk of progression, changes in lifestyle and diet can improve the treatment outcomes in MM patients.

Disclosures
No relevant conflicts of interest to declare.