With advances in treatment for multiple myeloma, some studies have reported improved survival rates, especially among young white patients and, to a lesser extent, in patients of other ethnicities.
But in a recent study, researchers at the University of Alabama at Birmingham show that these differences are not due to race itself, but instead to the socioeconomic differences observed between whites and ethnic minorities.
The study, “Impact of marital status, insurance status, income, and race/ethnicity on the survival of younger patients diagnosed with multiple myeloma in the United States,” published in the jurnal Cancer, shows that marital status, insurance status, and income — but not ethnicity — were all associated with a patient’s chance of survival.
Multiple myeloma, the second most common hematologic cancer, occurs mostly in black individuals. But despite substantial improvements in response rates and survival of myeloma patients in the last 20 years — due largely to the wider use of high-dose chemotherapy and autologous stem cell transplants — white patients have shown the greatest improvements in survival compared to ethnic minorities.
Also, improvements in survival are observed mainly in younger patients, with older patients showing smaller increases in overall survival rates.
A variety of factors are known to affect the survival of myeloma patients. These include the disease stage, gene expression patterns, age, race, the co-occurrence of other diseases, and response to treatment.
In this study, researchers hypothesized that due to the complexity and high cost of treatments, other sociodemographic factors could be influencing the survival of young myeloma patients, including income, insurance status, and marital status.
Although these factors had been extensively studied in more common solid tumors, no studies had evaluated their impact in myeloma patients, particularly among those diagnosed before age 65.
In their study, Dr. Luciano Costa, MD, PhD, and his colleagues examined data from more than 10,000 U.S. myeloma patients younger than 65. They found that the four-year overall survival was 71.1 percent in patients who were married, had insurance, and lived in a high-income county.
However, patients who had one, two, or three adverse sociodemographic factors saw their four-year overall survival drop to 63.2 percent, 53.4 percent, and 46.5 percent, respectively.
The adverse sociodemographic factors included being unmarried; uninsured or having Medicaid; and living in a low-income county.
As an example, compared to patients who were married, had private insurance, and lived in a medium- to high-income county, a patient who was unmarried, inunsured, and lived in a low-income county had a 25 percent lower likelihood of being alive four years after being diagnosed.
And although Hispanic and non-Hispanic black patients had a higher risk of death, when the researchers adjusted their data for marital status, insurance status, and income, as well as sex and age, they found that race or ethnicity no longer influenced survival of these patients.
This suggests that the apparent impact of ethnicity on survival may only be a consequence of disparities in sociodemographic factors among different ethnicities.
“This finding strongly suggests that there is a huge disparity in outcomes that could potentially be overcome by improving access and affordability of treatments,” Costa said in a press release.
“With the recent emphasis on comparative effectiveness in oncology, it also becomes crucial that all variables affecting outcomes — including sociodemographic factors — are accounted for when comparisons between different therapeutic approaches and healthcare systems are made.”