****An overlooked prognostic factor****
Current treatment decisions for diffuse large B-cell lymphoma (DLBCL) are primarily based on biological factors, such as the International Prognostic Index (IPI), which considers age, disease stage, performance status, and the number of affected areas outside the lymph nodes. First-line treatment generally involves a combination of CD20-directed monoclonal antibody with chemotherapy. However, we recognize a growing gap in current treatment guidelines: non-biological factors like socioeconomic status (SES) are not yet integrated, despite growing evidence that SES can influence cancer outcomes.
Studies from Denmark, the UK, and the US have shown that patients with lower SES tend to have poorer survival rates. Delays in receiving care, lower treatment intensity, or inadequate healthcare access were frequently cited as main reasons for explaining these disparities. Yet, non-medical factors such as employment status, income, and type of health insurance also play crucial roles in shaping a patient’s s treatment journey.
In our previous research focusing on the city of Hamburg – a population with excellent access to health care, statutory health insurance but also huge socioeconomic differences – we demonstrated that the introduction of rituximab-based treatments likely helped mitigate SES-related survival gaps. Building on this, we aimed to evaluate the long-term impact of SES for DLBCL survival across Germany as a whole. This nationwide study marks the first comprehensive analysis of its kind in the country.
****Understanding the interplay of regional deprivation, comorbidity burden and health care****
To assess how SES influences DLBCL survival, we analyzed data from the German Centre for Cancer Registry Data (ZfKD). Our dataset included all adult patients diagnosed with DLBCL between 2004 and 2019, totaling 49,465 cases. Alongside patient characteristics such as age, sex, place of residence, year of diagnosis, and history of other tumors, we also considered regional factors, including the presence of certified hospitals and premature mortality rates, the latter serving as a proxy for comorbidity burden.
We measured regional socioeconomic status using the German Index of Socioeconomic Deprivation (GISD). This index categorizes German country districts into low, middle, or high SES based on education, employment, and income levels. Using Cox proportional hazard models, we compared adjusted 5-year survival across these groups.
Our findings revealed strong disparities. Patients from low SES regions experienced worse survival rates compared to those from middle or high SES areas. However, when we accounted for premature mortality, the direct impact of SES diminished. This suggests that survival disparities were largely driven by lifestyle factors and comorbidity burdens rather than differences in access to or quality of cancer care.
****SES and comorbidities: Factors in DLBCL survival disparities:****
Our nationwide study documented large differences in 5-year survival across socioeconomic groups. Patients from middle and high SES areas had a 9–15% lower risk of mortality compared to their counterparts in low SES regions. These findings align with studies from other countries, such as Denmark, the UK, and the US, reinforcing the global relevance of socioeconomic factors in cancer care. At the same time, our findings also indicate that in settings with statutory health insurance, survival differentials are less driven by inadequate quality of care but rather comorbidities and unhealthy lifestyle that are themselves related to socioeconomic disadvantages. According to findings from the Swedish lymphoma registry, patients with comorbid conditions were less likely to receive curative treatment, which negatively impacted their overall survival. However, those who did undergo curative treatment showed no significant differences in lymphoma-specific survival. This highlights the critical need to address coexisting conditions, particularly in older patients, to ensure equitable treatment outcomes.
This is the first nationwide study in Germany to analyze the impact of regional SES on overall survival DLBCL patients, using one of the largest study populations worldwide. Despite its strengths, our study had limitations. The cancer registry dataset provided robust insights into patient demographics and tumor diagnoses but lacked detailed more specific prognostic variables like the IPI or Ann Arbor classification. While regional information as used in this study itself may not directly explain individual lymphoma survival, it serves as a powerful indicator of underlying health conditions affecting patient prognosis as same disease-related markers.
****Addressing SES-related factors: A key to improving DLBCL outcomes in Germany****
This nationwide study in a setting with statutory health insurance provides valuable insights for healthcare policymakers and professionals, offering evidence that addressing broader health disparities could have a profound impact on cancer outcomes in Germany. In sum, our findings suggest that while SES itself may not directly impact lymphoma survival addressing comorbidities and lifestyle factors in low SES patients could significantly improve long-term survival and close the gap between socioeconomic groups. Future research should uncover those comorbidities primary related to SES and survival in lymphoma patients to ultimately integrate strategies for their management in oncological treatment guidelines.
