Multiple Myeloma (MM) Clinical Characteristics, Prognostic Factors and Survival in Adolescents and Young Adults (AYA)

Background

Multiple Myeloma (MM) is considered as a malignancy of the elders (PMID: 28829925) but can also be seen in Adolescents and Young Adults (AYA) aged 15 to 39 years (PMID: 28829925). The prevalence of AYA-MM have been described between 0.8% to 9.6% (PMID: 32959221, PMID: 28829925). Younger MM patients have been considered to have better outcomes based on less frequency of comorbidities and increased tolerability to treatment, but non-standardized definitions of age range for young MM population make comparisons among literature difficult (PMID: 37722944). For patients <45 years, female gender and high income have been associated with better survival outcomes, and the impact of race is conflicting (PMID: 37541820). 3-year Overall Survival (OS) for AYA have been described as 80.2% (PMID: 28829925) and 5-year OS as 71% (PMID: 32959221). The objective of our study is to describe the clinical and sociodemographic characteristics, prognostic factors and survival in AYA-MM patients in the US.

Materials and Methods

Cases of MM classified in the 9732/3 diagnosis were obtained from the Surveillance, Epidemiology, and End Results (SEER) Database from 2000 to 2020. AYA age range was defined based on the National Cancer Institute (Ages 15–39, https://seer.cancer.gov/statfacts/html/aya.html). Statistical analyses were conducted with SPSS® version 25. Patient characteristics were reported in frequencies and compared with the Chi-squared test. The Kaplan-Meier method was used to estimate the median OS. Cox Regression was done to identify independent prognostic factors of survival. A p-value ≤0.05 was considered statistically significant.

Results

A total of 11,210 cases were identified. The median age at diagnosis was 75 years (IQR: 17). 78 AYA cases (0.7% of total population) were found. 51.3% of AYA were females, 42.3% were Non-Hispanic Whites (NHW) and 85.9% lived in metropolitan areas. A median income of ≥$75,000 was found in 25.6% of AYA. Chemotherapy was received by 43.6% and radiation therapy was given to 19.2%. The median OS for the AYA patients was not reached, with a 3-years OS of 86%. The median OS for the whole MM population was 23 months (CI 95%: 21.7-24.3).

Age groups comparisons found more NHW patients among the olders vs the AYA (64.8% vs 42.3%, p<0.001), more patients treated with chemotherapy among the AYA vs the olders (43.6% vs 29.8%, p=0.008) and that AYA patients were more prone to receive radiotherapy (19.2% vs 6.9%, p<0.001). The multivariate analysis specific for AYA population found that Hispanic patients had poor prognosis compared with other races (HR=9.1, CI 95%: 1.9-42.8, p=0.005).

Multivariate analysis performed for the whole population found that age is an independent prognostic factor for survival (HR=0.17, CI 95%: 0.1-0.3, p<0.001) in favor of the AYA. A better prognosis for patients diagnosed after 2016 vs before 2010 (HR=0.79, CI 95%: 0.74-0.85, p<0.001) was found. Compared to people with income <$35,000, the patients with income ≥$75,000 had better prognosis (HR=0.75, 95% CI: 0.62-0.89, p=0.002). Patients living in metropolitan areas showed better prognosis compared to those living in non-metropolitan areas (HR=0.91, 95% IC: 0.85-0.97, p=0.01). Better prognosis was found for NHB (HR=0.84, 95% IC: 0.79-0.89, p<0.001) and Asian-pacific patients (HR=0.86, 95% IC: 0.78-0.97, p=0.013) when compared to NHW. No difference was found for Hispanics (p=0.14).

Better prognosis was found for patients that received chemotherapy vs no-chemotherapy (HR=0.68, 95% IC: 0.65-0.72, p<0.001), meanwhile Beam radiotherapy was associated with increased mortality risk (HR=1.14, 95% IC: 1.05-1.24, p=0.002). No difference was found for gender (p=0.67).

Conclusions

Our study confirms an advantage in OS for younger age and add new information of the impact of race in OS for AYA. Factors such as income, place of residency and treatment were not found to have an impact on AYA, but are prognostic factors for OS in the whole MM population. Limitations include the sample size of the AYA population. Standardization of age ranges defining AYA such as the NCI range to facilitate comparisons of outcomes among literature is needed.