CHICAGO—Survival rates for multiple myeloma have improved considerably in recent decades thanks to the advent of novel drugs, stem cell transplantation, and management strategies, but this survival gain is not consistent among all patients. Disparities in multiple myeloma care exist, particularly among patients who live in rural areas or who belong to minority populations, and this topic was the focus of an educational session titled “Many Shades of Disparities in Myeloma Care” at the 2019 ASCO Annual Meeting.
“Let us first accept that we have a problem,” said the presenter Siddhartha Ganguly, MD, FACP, Professor of Medicine in the University of Kansas Health System. “Universal access to quality health care remains a challenge globally, as well as here in the United States.”
When patients don't have the same access to care, survival differences can be seen. For example, a study of patients in New Mexico showed that for myeloma patients from rural zip codes, the median survival was almost half of that seen in patients from urban areas (Biomed J Sci Tech Res 2017;1:579-585).
Experts have questioned whether disease characteristics differ in multiple myeloma, thus explaining the mortality differences seen, but currently there is limited evidence. A case-control study showed that farming for more than 10 years was linked to a greater risk of being diagnosed with multiple myeloma, but Ganguly cautioned that the study was observational in nature (Cancer Nurs 2009;32:456-464).
Part of the problem is the uptake of, and access to, treatments may not be the same across patient populations. For example, although an accepted treatment to improve survival for multiple myeloma, stem cell transplantation is not consistently used by all patients. A study showed that while the overall stem cell transplantation utilization rate was 30.8 percent in 2013 for patients, the rate varied by race. Non-Hispanic white patients had the highest uptake (37.8%) followed by non-Hispanic black patients (20.5%), and Hispanic patients (16.9%) had the lowest uptake (Cancer 2017;123(16):3141-3149). Another study found that, in an adjusted analysis, the odds of receiving stem cell transplantation were significantly higher among Caucasian patients compared with African-American patients (OR=1.75; 95% CI, 1.64-1.86; P<0.01) (Cancer 2010;116(14):3469-3476).
Furthermore, these differences in access to treatments can create survival differences. For instance, a study found that blacks were 37 percent less likely to have a stem cell transplantation and they were 21 percent less likely to be treated with bortezomib (Cancer 2017;123(9):1590-1596). “More importantly, what [the researchers] were able to show was that underutilization of these modalities was associated with 12 percent increased hazard of death,” said presenter Sikander Ailawadhi, MD, Associate Professor in the Division of Hematology-Oncology at Mayo Clinic. “Clearly if you don't get the patient the right treatment, survival is going to be poor.”
Clinical trial participation also differs by race, with the majority of patients being non-Hispanic white (83.4%), a study found (J Oncol Practice 2017;14(1):e1-e10). African-American patients made up only 6 percent of clinical trial participants and Hispanic 2.6 percent. Furthermore, the enrollment fraction, which considers a minority groups' representation in the overall population and their enrollment in trials, was 1.2 percent for non-Hispanic whites, 0.7 percent for African-Americans, and 0.4 percent for Hispanics. “This is dismal,” Ailawadhi said about the enrollment fractions of minority groups.
Because of a lack of disparities research, there may be areas where disparities exist but are currently not recognized. Take, for example, the adoption of triplet therapy among patients with newly diagnosed multiple myeloma. The use of triplet therapy has increased substantially from 8.7 percent in 2000 to 61.3 percent in 2014, but whether this trend is consistent for all patients is currently unknown (Leukemia 2017;31:1915-1921). “Awareness of using novel drugs in multiple myeloma has clearly advanced; but is this positive trend true for both urban and rural populations?” asked Ganguly, noting that currently the question is unanswered.
“We are left with more questions than answers because of lack of data,” said Ganguly, speaking broadly about disparities research.
The belief is that if patients had the same access to treatments, then the disparities gap would close, and studies are increasingly supporting this idea. For instance, a 2018 study evaluating the outcomes of rural and urban patients treated in 44 phase III and phase II/III SWOG clinical trials found no statistically significant difference in overall survival, progression-free survival, or cancer-specific survival (JAMA Netw Open 2018;1(4):e181235).
“If [patients are] given the proper opportunity, the outcomes are not different in clinical trials,” Ganguly summed up. The same trend can be also seen for stem cell transplantation. “Whether your Hispanic, African-American, Caucasian—the transplantation utilization rate is low—but as long as you get the transplant, the survival rates are the same,” he concluded.
Christina Bennett is a contributing writer.