Survival Difference in Multiple Myeloma By Place of Birth

Introduction:

Multiple Myeloma (MM) survival has improved in last decade with better understanding of disease process and use of novel agents. There is limited data if there is survival difference in MM by place of birth. We choose United States and South Asian Association for Regional Cooperation (SAARC) countries to see if there any difference in survival among these two geographical regions. SAARC consists of 8 south Asian countries: Afghanistan, Bangladesh, Bhutan, India, Sri Lanka, Nepal, Maldives and Pakistan.

Methods:

We analyzed Surveillance Epidemiology and End Results (SEER), SEER 18 registry to compare relative survival (RS) of US born and SAARC countries born MM patients, who were diagnosed with MM during (1973-2011). We analyzed RS during three eras: pre transplant era (1973-1995), transplant era (1996-2002) and era of novel agents (2003-2011) by age (≤65 and >65 years) and sex. We used SEER*Stat software to calculate Z value.

Results:

There were 228 SAARC born and 42,629 US born MM patients diagnosed during (1973-2011). Median age of diagnosis for SAARC countries born MM patients was 64 years (range: 27-88) and 82 of them were female. Median age of diagnosis for US born MM patients was 68 years (range: 18-99) and 19,385 of them were female.

There was no significant difference in RS between SAARC born and US born MM patients during pre-transplant and transplant eras. In the era of novel agents, RS of SAARC born MM patients was significantly higher compared to US born MM patients (64±5.1% vs 47.6±0.5%, Z value 3.4) at 3 years and (47.6±6.2% vs 32.2±0.5%; Z value 3.3) at 5 years.

Analysis by sex showed, both male and female SAARC born MM patients had higher RS compared to US born MM patients at 3 and 5 years during era of novel agents.

Similarly, younger (≤65 years) SAARC born MM patients had significantly better survival than US born MM patients at 3 and 5 years. Older (>65 years) SAARC born MM patients also had significantly better survival at 3 years but there was no significant difference at 5 years.

Conclusions:

Our study showed that there is survival difference Multiple Myeloma patients by place of birth. MM patients born is SAARC countries have better survival than patients born in US. It could possibly be related to difference in disease biology, socioeconomic status and access to health care. We need more studies in future to confirm these findings and individualise treatment plan.