Treatment Patterns and Survival Outcomes in Elderly Veterans Diagnosed with Diffuse Large B-Cell Lymphoma

Introduction: Diffuse large B-cell lymphoma(DLBCL) is the most common non-Hodgkin's lymphoma and its incidence steadily increases with age. The elderly population diagnosed with DLBCL are a heterogenous group with no standardized age cut-off in literature. There is also a paucity of data regarding the treatment of elderly DLBCL patients due to lack of participation and/or inclusion in clinical trials. The VHA (Veterans Health Administration) is one of the largest integrated provider of cancer care in the United States and its population, on average, is older than the general US population, giving us a unique advantage in exploring real-world outcomes in this elderly population.

Methods: This is a retrospective chart review of 5199 randomly selected patients with an ICD code for lymphoma treated within the VHA between 1/1/2011 and 12/31/2019. Data abstractors collected baseline patient and disease characteristics and treatment responses. Survival time was determined via electronic health record query on 7/25/2022. Chi-square tests were used to analyze the relationship between age and variables of interest.

Results: Of the 2697 patients that met the inclusion criteria, one-third of the patients were <65 years (n=916, 34%) and two-thirds of the patients were ≥65 years(n=1781, 66%) out of which 51.5%(n=1390) were within 65-79 years and 14.5% were above 80 years (n=391). Though ECOG status decreased with increasing age, more than 2/3^rd of the patients within each of the above subgroups had a preserved ECOG score of 0-2. ABC phenotype was statistically more common in patients >80 years when compared to <65 years and 65-79 years as shown in Table 1. No difference was seen in the distribution of double or triple hit status between the three groups.

The percentage of patients that did not receive any treatment increased with age (3.2% vs 6% vs 20.7% in <65, 65-79 and >80 year groups respectively, p<0.001), and the number of patients receiving 2 or more lines of treatment decreased with age (10.2% vs 7.5% vs 2.3%, p<0.001).

Across all age groups, R-CHOP remained the common first-line regimen (73.3%, 67.9%, 39.1%) with more proportion of the >80 years group receiving R-mini-CHOP (0.3% vs 2.1% vs 15.1%) when compared to the other groups. In terms of completion of first-line treatment(R-CHOP or R-mini-CHOP), patients <65 years were more likely to complete 6 cycles when compared to patients >65-79 and 80 years (73.9% vs 67.8% vs 59.8%, p<0.001).

The overall median OS decreased with increasing age, 63.7 months in <65 years, 48.3 months in 65-79 and 23.6 months in >80 years age group. Patients of all age groups, who received 6 or more cycles of first-line anthracycline-based regimen had almost double the duration of 1-, 2- year and overall survival when compared to patients who received ≤5 cycles as shown in Table 2.

Conclusion: Veterans older than 65 years who are diagnosed with DLBCL present with a higher stage of disease, higher IPI score and ABC phenotype. Amongst them, the very elderly patients older than 80 years old had the shortest survival along with low treatment initiation and completion rates despite comparable functional status at diagnosis. When able to complete 6 or more cycles of first line R-CHOP/R-mini-CHOP they attained almost double the duration of median OS when compared to receiving <6 cycles of chemo-immunotherapy. Given that the incidence of DLBCL has been increasing over the age of 65 years, therapeutic approaches that optimize treatment efficacy while minimizing toxicity are needed. With the advent of genomic profiling and identification of molecular abnormalities in DLBCL, novel antibodies or small molecules with relatively low toxicity can increase tolerance in upfront setting leading more elderly patients towards completion of necessary lines of treatment and improved overall survival.

Nooruddin:Astrazeneca: Research Funding.