Longer Survival for Black vs White Myeloma Patients With Same Care
Black people with multiple myeloma live longer than white patients with similar disease symptoms when both receive the same new and updated medical treatments, according to an analysis of the Surveillance, Epidemiology, and End Results (SEER) database.
However, Black myeloma patients were less likely to receive such novel treatments than white individuals — even when matched for demographics, socioeconomic status, and co-existing medical conditions, the analysis showed.
“Our findings reinforce the importance of equitable access to effective treatment modalities to further improve the survival of [Black] patients with [multiple myeloma],” the researchers wrote.
Notably, with similar symptoms, non-Hispanic Black patients had “significantly longer 5-year survival” than non-Hispanic white people when given like treatment for the rare blood cancer.
The database analysis was published in the Blood Cancer Journal, in a study titled “Black patients with multiple myeloma have better survival than white patients when treated equally: a matched cohort study”
Among non-Hispanic Black people, myeloma occurs up to three times more often, starts at a younger age, and has more than double the mortality rate compared with non-Hispanic white patients, previous research has found.
Studies have suggested that Black myeloma patients also have lower rates of treatment with new therapeutic agents, but whether these lower treatment rates translate into worse outcomes remains unclear.
Now, using data from the SEER Medicare database, which contains information on cancer statistics, researchers based at the Medical College of Wisconsin Cancer Center examined ethnic disparities in myeloma survival and associated factors.
“We sought to study whether [white] patients with MM [multiple myeloma] who present similar to [Black] patients with MM receive similar myeloma therapies as [Blacks], and if not, to what extent treatment differences explain the disparities in survival,” the team wrote.
Overall, 24,150 patients, newly diagnosed with myeloma between 1999 and 2017, were selected for the analyses. These included 3,319 non-Hispanic Blacks (13.7%) and 20,831 non-Hispanic whites (86.3%). On average, Black patients were younger than whites (76.1 vs. 77.1 years), more likely to be female (60.0% vs. 48.0%), and unmarried at diagnosis (42.0% vs. 25.2%).
Black individuals also had lower socioeconomic status (SES) scores — based on neighborhood poverty, income, and education level — but more co-existing medical conditions, or comorbidities.
To properly compare treatment and outcomes in these two populations, four groups of 3,319 white patients were matched with the same set of 3,319 Black patients. In each group, matching was based on demographics (sex, age at diagnosis, marital status, year of diagnosis, and SEER site); socioeconomic status (SES, plus demographics); disease presentation factors (SES plus demographics and comorbidities), and treatment-related factors (myeloma therapies plus disease presentation, demographics, and SES).
When compared with the demographics-matched sample of white patients, Black patients were significantly less likely to be treated with proteasome inhibitors (28.3% vs. 32.7%), immunomodulatory therapies (16.4% vs. 21.3%), and stem cell transplantation (3.8% vs. 6.4%).
Similar disparities were seen in the groups matched for socioeconomic status and disease presentation. There was, however, no difference in the use of traditional chemotherapy between the two groups.
Statistical analysis of these data showed that ethnicity, sex, year of diagnosis, age at diagnosis, marital status, SEER site, and socioeconomic status significantly influenced who received these novel treatments.
During follow-up, 16,479 white patients (79.1%) and 2,595 Black patients (78.2%) died. In demographically-similar patients, the median survival time was similar between the two groups (30.0 vs. 32.0 months).
However, the median survival times after matching socioeconomic status, then presentation, followed by treatment, sequentially lowered median survival times in white patients from 32 months to 30 to 28 to 26 months.
Therefore, when Black and white patients had the same disease presentation and myeloma treatment, Black individuals showed a significantly longer median survival time – 30 months vs. 26 months.
Likewise, while the five-year survival was similar in demographically-matched groups, significantly more Black patients survived five years when groups were matched based on presentation or treatment.
Compared with Black myeloma patients with the same disease presentation, white patients had a 9% relatively higher mortality risk at five years. The relative risk increased to 13% after matching treatments.
Exploring the data over time found that, before 2003, when chemotherapy remained the primary treatment for myeloma, there were no survival differences between the two groups, “which likely reflected the factor that no difference in chemotherapy was observed in our study,” the researchers wrote.
For those diagnosed between 2003 and 2007, when new myeloma therapies became available, the difference in survival rates between Black and white patients was significant only after matching treatment regimens.
For patients diagnosed in 2008 and later, a time when 75% of newly diagnosed myeloma patients received a new myeloma therapy, the treatment-matched survival difference was only marginally significant, “indicating that the widespread use of novel agents helped to reduce the racial survival disparity,” the researchers added.
“In summary, in the SEER-Medicare population, [non-Hispanic Blacks] with MM were less likely to receive novel antimyeloma treatment and [stem cell transplant] compared with [non-Hispanic whites], and these disparities in treatment could not be explained by sociodemographic factors,” the investigators wrote.
“Although the [overall survival] was comparable between [non-Hispanic Blacks] and [non-Hispanic whites] across the entire population, [non-Hispanic Blacks] had a superior survival when they were treated similar as [non-Hispanic whites],” they added.
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