An International Comparison Of Survival Disparities In Patients With Lymphoma and Myeloma
Authors: Pulte Dianne , Redaniel Theresa , Jeffreys Mona 
Published: October 2019

Abstract

Background
Relative survival in older patients with lymphomas is significantly lower than in younger patients. Possible reasons for the discrepancy may include increased aggressiveness of the disease in older patients, increased frailty and co-morbidities complicating treatment in older patients, and under-treatment of older patients due to concern about increased risk of intolerance to treatment. Distinguishing between these problems on a population basis can be difficult as clinical trial data often provides data only on the “ideal” patient and may not be applicable to the general population. Here, we determine 5-year relative survival and excess mortality by age for patients diagnosed with Hodgkin's lymphoma (HL), non-Hodgkin lymphoma (NHL) and multiple myeloma.

Methods
Data was obtained from the Surveillance, Epidemiology, and End Results (SEER) database in the United States (US) and Cancer Registry data covering the whole of England (UK) for all patients diagnosed with HL, NHL and myeloma between 1996 and 2010. Five year relative survival was calculated by categories of age (15-24; 25-44; 45-64; 65-74 and 75+ years) using period analysis. Relative survival was calculated using age, race, gender, and country specific life tables. In addition, region specific life tables were used in the UK. Excess mortality modellingwas used to determine excess risk for older compared to younger patients, using patients age 25-44 for the reference group.

Results
Five year relative survival was lower for older patients diagnosed with HL, NHL, and myeloma in the US and UK. The most dramatic difference in survival by age was observed for patients with HL among whom survival for 15-24 year olds was 96.2% and 92.5% in 2006-10 in the US and UK, respectively but only 51.0% and 22.8%, respectively, for patients age 75+, representing an excess mortality of 14.02 (95% CI 12.22-16.09) and 15.69 (14.21-17.33), respectively, for the US and UK for patients age 75+ compared to 25-44. Similar, although less extreme, differences were observed for NHL and myeloma (see Table). Excess mortality ratios of 1.91 (1.84-1.99) and 3.81 (3.67-3.96) was observed for patients with NHL at age 75+ as compared to 25-44 in the US and UK, respectively. For patients with myeloma, excess mortality ratios of 2.79 (2.52-3.09) and 3.60 (3.27-3.962) for patients age 75+ compared to 25-44 were observed, respectively, for the US and UK. Adjustment for gender, ethnicity, period of diagnosis, and income (UK data only) did not significantly affect excess mortality ratios.

Conclusions
Survival of patients with lymphoma, especially patients with HL, is dramatically lower for older patients in both the US and UK. Older patients with lymphoma had a higher survival in the US as compared to the UK. This finding suggests that older patients in the UK may experience under-treatment. Physicians should be encouraged to evaluate patients' frailty and co-morbidities as well as their age when considering treatment options for patients with lymphoma and myeloma.

Disclosures:
No relevant conflicts of interest to declare.