Many hematologic malignancies most commonly affect older adults. For example, the median age at diagnosis of acute myeloid leukemia (AML) is about 65 years, while the median age at presentation of MDS is more than 70 years, and the risk of MDS and AML continues to rise with advancing age.
Historically, the potentially curative option of allogeneic hematopoietic stem cell transplant (HSCT) was not offered to most adults over the age of 65 due to increased relapse risk, the high frequency of comorbid conditions that make transplant-associated conditioning and immunosuppression difficult to tolerate, and high rates of non-relapse mortality (e.g. infection, graft-versus host disease (GvHD)) even in patients without serious comorbid conditions.
In the last decade, however, the number of allogeneic transplants in the older population has been increasing. According to Center for International Blood and Marrow Transplant Research (CIBMTR) data, the number of allogeneic transplants performed for patients over the age of 60 more than doubled from 2007 to 2013 compared with 2000 to 2006. The increase in transplants has been influenced by the availability of reduced-intensity conditioning regimens that are less toxic, as well as the growing use of alternative stem cell sources, including umbilical cord blood and haploidentical donors.
In 2013, our transplant program conducted a retrospective analysis of outcomes in Dana-Farber patients over the age of 70 years who underwent allogeneic HSCT, most of whom had this procedure done for MDS or AML. The results of this review were encouraging. The incidence of non-relapse mortality was low – only 5.6% at 1 year. Progression-free and overall survival were both about 40 percent at 2 years. Acute GvHD was seen in 13 percent of patients at 200 days and chronic GvHD in 36 percent of patients at 2 years.
These data are similar to a large CIBMTR study that concluded age over 65 did not significantly impact non-relapse mortality, disease-free survival or overall survival. These studies suggest that reduced-intensity allogeneic transplant is an effective and tolerable option for older adults in their 60s and 70s. We have successfully transplanted otherwise healthy patients with AML or MDS in their late 70s. Given these results, it is important to encourage early referral for transplant consultation. Age alone should no longer be a barrier to evaluation for, and consideration of, transplant.