Abstract
Introduction: High-dose melphalan followed by autologous hematopoietic cell transplantation (auto HSCT) has become the standard procedure for patients with symptomatic multiple myeloma (MM). Retrospective analyses suggest that the benefit of HDT extends to elderly myeloma patients, which is an important finding considering that the median age at diagnosis is 69 years (range: 65-74) for MM in United States, using 2010-2014 US SEER data. The aim of our study was to determine the effect of age on stem cell collection and engraftment in patients with MM.
Materyal and Methods: From January 2010 through April 2016, data from 260 myeloma patients below the age of 65 were compared to 41 myeloma patients above 65 years of age who were eligible for auto HSCT according to geriatric assessment (GA), depending on the results of IMWG report in 2015. All these data were obtained from the Ankara University Faculty of Medicine Center for Therapeutic Apheresis and written informed consent was signed according to our institution regulations. Mostly bortezomib based regimens were given as induction therapy to our patients. Ninety two percent of the patients received only GCSF at a dose of 5 µg/kg BW twice-daily s.c. until stem cell procurement. Patients underwent further PBSC collections until we obtained the target dose >20 CD34+ cells/µL blood. A maximum of 3 collections were performed in the first mobilization; if the cell dose was not achieved, we submitted patients to a second mobilization.
Results: Forty-one of 301 patients were above 65 years of age (median age 68, range 65-75) and 260 patients were below the age of 65 (median age 56, range 29-64). Baseline characteristics of the older and younger patient cohorts are summarized in Table-1. The median follow-up was 48.5 months (range 1-90) for age <65 years old patients and 46 months (range 1-90) for age ≥65 years old patients. Mobilization regimens for the younger patient population were G-CSF only (n:241), cyclophosphamide based (n:12) and +plerixafor (n:7). Mobilization in the older population was with cyclophosphamide based (n:4), G-CSF only (n:36) and +plerixafor (n=1) in whom poor mobilization had been predicted. The chemotherapy regimens were not statistically different between both age groups (chi square p value 0.37). There were no significant statistical differences in time from diagnosis to mobilization, number of prior therapies or disease status between both patient groups. The number of CD34-positive circulating cells before scheduled leukapheresis was mean 23.26 cells/μL in all patients (including patients who failed mobilization). Neutrophil engraftment was seen faster in elderly group (mean 10.4±3.1 vs. 11.5±1.8; p=0.008) but platelet engraftment was similar compared the younger patients with older ones (Table-2). In The probability of 5-year progression free survival (PFS) and overall survival (OS) in elderly patients with ISS-3 was 82.4%±12.1% and 48.5±16.5%. No statistical significance was observed for mean estimated 5-year OS in terms of patient age (<65 and ≥65 years; 82.5%±2.8% and 74.3%±8.7% p=0.29) (Figure-1). Less relapse was occurred in elderly cohort (17.5% vs. 35.4%) but the number of patients in this group does not provide enough statistical power to confirm whether the differences in PFS were statistically significant.
Conclusion: To date, accepted approach for elderly patients with MM is not only improving survival, also their quality of life. Based on this single center study, auto-HSCT is safe and efficient in the treatment of elderly myeloma patients but no statistical difference was demonstrated in respect to age groups.
Ilhan: Novartis: Consultancy.
