The Characteristics, Treatment Patterns, and Outcomes of Older Adults with Multiple Myeloma

Background: Advances in the treatment for multiple myeloma (MM) have dramatically improved outcomes for younger patients. Older adults, particularly those 80 years of age or older at diagnosis, have seen more modest gains. MM incidence increases with age, and as more of the population is living later into life, the segment of the MM population over 80 will continue to grow. In this study, we sought to better understand the characteristics, treatment, and outcomes of older patients with MM.

Methods: We identified all patients diagnosed with MM at age 80 or older in the Surveillance, Epidemiology, and End Results Program (SEER) database from 2007-2013 to determine incidence and outcomes. Subset analysis was then performed on patients included in the SEER-Medicare linked database who were enrolled in Medicare Parts A, B, and D to further explore patient characteristics and treatment patterns.

Results: The incidence of MM increases over age, peaking after age 80. The annual incidence for those aged 65-69, 70-74, 75-79, 80-84 and 85+ was 24.4, 32.7, 39.5, 42.8 and 36.4 per 100,000, respectively. Based on 2010 US population estimates, approximately 4,500 new cases of MM were diagnosed annually 2007-2013 in patients age 80 or older. In that period, 8,093 cases, approximately 1,150 per year, were reported to SEER. The estimated median overall survival (OS) of these patients was 14 months (95% CI 13.2-14.8). The estimated relative 12 month survival was 58.9% (95% CI 57.4-60.4) compared to their peers without cancer.

Of the 8,093 cases of MM reported to SEER during the study period, 2,385 were present in the SEER-Medicare linked dataset. Of these, 225 were identified as smoldering MM using a previously established algorithm (Fiala, et al, JCOCCI, 2018) and excluded leaving 2,160 for the analyses. The median age was 84 (range 80-100) and 55% were female. 81% were white, 13% black or African-American, and 6% another race. At disease presentation, 22% had claims indicating hypercalcemia, 61% renal failure or chronic kidney disease, 59% anemia, and 34% MM bone involvement. The estimated median OS was 13.4 months (95% CI 12.2-15.1).

Only 52% of patients had claims indicating they received systemic MM treatment within 6 months post-diagnosis. Nearly all that did received novel agents; 38% received bortezomib-based treatment, 41% immunomodulatory drug (IMID)-based, and 14% both. The others received antineoplastic chemotherapies such as melphalan or cyclophosphamide. Interestingly, bortezomib utilization increased incrementally from 25% of patients treated in 2007 to 62% in 2013 while IMID utilization declined from 67% to 49%.

The median OS of those receiving treatment was 21 months (95% CI 18.5-23.1) compared to 6.3 months (95% CI 5.3-7.3) for those who did not (p <0.0001). MM treatment was associated with a 26% decrease in hazard for death (aHR 0.74; 95% CI 0.67-0.82; p < 0.0001) independent of age, race, gender, poverty, comorbidities, and proxy measures of performance status. Outcomes improved for patients in more recent years; the hazard for death decreased by 3% (HR 0.97; 95% CI 0.94-0.99; p = 0.0096) each year 2007-2013. This can be attributed to increasing treatment rates. In 2007, only 41% of patients received treatment compared to 61% in 2013. After controlling for MM treatment, the year of diagnosis was no longer a significant predictor of survival.

Conclusions: The outcomes of patients with MM over 80 years old are still relatively poor; nearly half of the patients do not receive systemic treatment and for those who do the median OS is just 21 months. The population over 80, when MM incidence peaks, is projected to triple over the next few decades. It is imperative that we improve our understanding of the needs of this vulnerable subgroup of patients of MM.