The treatments available for multiple myeloma (MM) have evolved over time, improving survival for those with the disease. Although it is known that there are racial disparities in MM treatment and prognosis for patients, it has been established that non-Hispanic African American (NHAA) individuals are twice as likely to develop and die from MM compared to their non-Hispanic White (NHW) counterparts. Authors of a new study published in Cancer Medicine evaluated the treatment patterns and survival of MM among older patients and assessed racial differences in the receipt of treatment, timing of treatment initiation, and survival between NHAA and NHW Medicare beneficiaries with MM within real-world settings.
A total of 2094 NHAA and 11,983 NHW patients with MM aged 66 years and older were included in the study. The enrolled patients were diagnosed with MM between 2007 and 2017 with no previous cancer diagnoses, enrolled in Medicare A & B continuously, and had no previous enrollment in health maintenance organizations from 12 months prior to diagnosis to death or December 31, 2019, whichever occurred first. In addition, the study utilized the Surveillance, Epidemiology, and End Results (SEER)-Medicare database to link patient-level cancer information of Medicare beneficiaries from SEER registries with individual-Medicare claims (eg, inpatient, outpatient, physician services, hospice care, prescription drugs). MM treatment was defined as the receipt of belantamab, bendamustine, bortezomib, carfilzomib, carmustine, cisplatin, cyclophosphamide, daratumumab, doxorubicin, elotuzumab, etoposide, isatuximab, ixazomib citrate, lenalidomide, melphalan, panobinostat, pomalidomide, selinexor, thalidomide, vincristine, unspecified antineoplastic chemotherapy or immunotherapy, or autologous or allogeneic stem-cell transplant.
Key Takeaways
- Racial Disparities in Patients With Multiple Myeloma: Non-Hispanic African American (NHAA) patients with multiple myeloma (MM) are twice as likely to develop and die from the disease compared to non-Hispanic White (NHW) patients. This study aimed to evaluate treatment patterns and survival among older patients with MM, focusing on racial differences in treatment receipt, timing, and overall survival.
- Disparities in Treatment: The study included 2,094 NHAA and 11,983 NHW Medicare beneficiaries aged 66 and older with MM. According to the analysis, NHAA patients were more likely to be female, younger, unmarried, and have Part D enrollment. Although the proportion of treated patients increased in both groups over time, NHAA patients were still more likely to experience delays in MM treatment initiation compared to NHW patients.
- Survival Rates in 2 Patient Groups: After adjusting for baseline characteristics, NHAA patients had later treatment initiation than NHW patients; however, survival rates were similar between NHAA and NHW patients who received treatment. NHAA patients without treatment within the first year also had a reduced risk of death compared to NHW patients, highlighting complexities in the relationship between race, treatment, and survival. The study authors emphasize the need for addressing racial disparities and barriers to MM treatment access.
The study’s main endpoint was 5-year overall survival (OS). The authors note that in order to reduce the risk of potential immortal time bias, patients who did not receive a MM-related treatment within the first year after diagnosis were randomly assigned a pseudo-treatment initiation date. In addition, the secondary outcome was time to initiate treatment. Patients were followed from treatment imitation (patients who received treatment within the first year after diagnosis) or from pseudo-treatment initiation (patients who did not undergo treatment within the first year) until death, 5 years following treatment initiation, or December 31, 2019, depending on which came first.
Patient characteristics (eg, age at diagnosis, sex, marital status, residential region, and socioeconomic status) were summarized at diagnosis (baseline). In addition, the year of MM diagnosis (2007-2009, 2010-2013, or 2014-2017) was recorded.
The investigators followed NHAA and NHW patients for a median of 1.88 years (IQR: 0.44–3.92) and 2.17 years (IQR: 0.50–4.27), respectively, with median ages of 75 years (IQR: 70–81) for NHAA patients and 77 years (IQR: 71–83) for NHW patients. NHAA patients were more likely to be female, younger, unmarried, and have Part D enrollment, unlike NHW patients.
During the first year following MM diagnosis, approximately 59.5% of the NHAA patients and 64.8% of the NHW patients received treatment. In the NHAA group, patients who received treatment within 1 year of diagnosis increased from 51.5% in 2007 through 2009 to 64.5% in 2014 through 2017, and the NHW group increased from 54.3% to 71.4% during the same period. Although the discrepancy in the proportion of patients treated for MM in the first year between the 2 groups was not considered significant in 2007 through 2009, it was statistically significant in 2010 through 2013 and 2014 through 2017.
Further, after adjustments were made for baseline characteristics, treatment initiation was still noticeably later among the NHAA patient population than in NHW patients (HR = 0.91, 95% CI: 0.85–0.97, p < 0.01), with treatment initiation earlier for patients diagnosed in more recent periods (2014–2017: HR = 1.54, 95% CI: 1.46–1.63; 2010–2013: HR = 1.37, 95% CI: 1.30–1.44) than for those diagnosed in 2007 through 2010. In addition, in the separate analysis for treatment status, it was determined that NHAA and NHW patients who received treatment had similar survival rates (HR = 0.98, 95% CI: 0.90-1.06, p = 0.63); however, NHAA patients without any treatment within the first year of diagnosis had a reduced risk of death compared to NHW patients (HR = 0.84, 95% CI: 0.77-0.98, p < 0.01). The investigators noted that the year of MM diagnosis was a predictor of survival for patients who received treatment for MM but did not give an indication being associated with survival among patients who were not treated.
Limitations of the study include a lack of information on why treatment was delayed or not initiated, the database’s exclusion of information on individual-level socioeconomic status, and the limited patient population (individuals aged ≥66 with continuous Medicare fee-for-service coverage), resulting in the analyses not being applicable to younger individuals or those who are covered by other insurances. Further, the study authors emphasize the lack of comprehensive clinical, laboratory, and pathologic details in the SEER-Medicare database, noting that it prevented an accurate evaluation of disease stage, severity, and cytogenetic risk factors that could impact MM treatment choices and survival.
Although there are multiple therapeutic options available for treating MM, the findings presented an increasing trend of racial disparities present in the utilization of treatment. Because of the price of novel agents, inequity may continue to increase if financial burden is the barrier for NHAA patients with MM who are trying to access care. The authors note that despite changes such as the Affordable Care Act and Inflation Reduction Act, further measures need to be made to eliminate racial disparity and barriers to treatment for NHAA patients.
Reference
Wang R, Neparidze N, Ma X, Colditz GA, Chang S-H, Wang S-Y. Racial differences in treatment and survival among older patients with multiple myeloma. Cancer Med. 2024; 00: 1-11. doi:10.1002/cam4.6915
