Autologous Stem Cell Transplantation in Patients of 70 Years and Older With Multiple Myeloma: Results From a Matched Pair Analysis

Thanks to Carol for finding this new study.

Autologous Stem Cell Transplantation in Patients of 70 Years and Older With Multiple Myeloma: Results From a Matched Pair Analysis
Am J Hematol. 2008 Aug 1;83(8):614-617, SK Kumar, D Dingli, MQ Lacy, A Dispenzieri, SR Hayman, FK Buadi, SV Rajkumar, SV Rajkumar, MA Gertz

Multiple myeloma (MM) accounts for 1% of all malignancies and approximately 10% of all hematologic malignancies. In the United States, an estimated 19,900 new cases of MM were diagnosed in 2007, and 10,790 patients were expected to die of this disease. Patients with MM have a median age of onset in the seventh decade of life and 3- to 4-year median survival when treated with conventional chemotherapy. Newer combination chemotherapeutic agents have not improved the survival outcome achieved with melphalan and prednisone, which have been used for >30 years. High-dose chemotherapy (HDT) followed by autologous stem cell rescue has resulted in improved survival and quality of life compared with conventional strategies. For patients with MM who qualify for HDT, this approach has become the standard of care.

Many of the larger clinical trials in which HDT was examined only included patients <65 years of age. However, a significant proportion of MM patients are >65 years. Therefore, it remains unclear whether the benefits observed in younger patients would extend to an older population. This case-controlled study evaluated the outcome of HDT in patients with MM who were >70 years.

A total of 93 patients were included in the study. All had undergone HDT and stem cell transplantation for MM. The study group included 33 patients >70 years and a matched control group of 60 patients <65 years. The baseline characteristics of the 2 groups were comparable, with the only difference being the type of conditioning regimen used. The dose of the melphalan conditioning regimen was reduced in 30% of patients in the elderly group as opposed to only 5% of patients in the younger group.

A trend toward a longer hospital stay after transplant was noted for the elderly vs the younger group (8 vs 3 days). By day 15, engraftment occurred in 94% of the elderly group vs 78% of the control group (P = .08). The adverse reactions most often seen were nausea, vomiting, hypertension, and tachycardia; no significant differences between the groups were evident. The overall response rates were 97% and 98% for the elderly and control groups, respectively. A complete response was achieved by 42% of the elderly group vs 28% of the control group. The patients were observed for a median of 27.2 and 38.3 months in the elderly and younger groups, respectively. The post-transplant median overall survival duration was 53.3 months in the younger patient group; the elderly patient group did not reach its median overall survival during follow-up. In the subset of patients receiving reduced-dose melphalan, there was no difference in time to progression or overall survival compared with
patients receiving standard-dose melphalan.

Previous trials have clearly shown a benefit of HDT in patients <65 years of age. However, investigators have not studied the benefit of HDT for patients 70 years of age and older. This study showed that patients older than 70 years have outcomes similar to those in younger patients (<65 years of age). The treatment-related mortality rate and the kinetics of engraftment were similar between the 2 study groups. Despite a greater proportion of the older group of patients receiving a reduced dose of melphalan, no significant differences were evident with respect to response rate or time to progression between the 2 groups. This retrospective study showed a benefit for patients >70 years who underwent HDT for MM. Age alone should not be the sole factor used when evaluating whether a patient is eligible to undergo HDT. Dose reduction should be considered for the older population of patients when appropriate.