Treatment Selection and Survival in Patients with Gray Zone Lymphoma: A Comprehensive Population-Based Analysis.

Abstract

Background and objectives: There are no treatment guidelines for gray-zone lymphoma (GZL), given the disease's rarity and being a relatively new entity. Our objective was to assess factors affecting treatment selection in GZL and its effect on survival, focusing on combined modality treatment (CMT) versus chemotherapy alone.

Patients and methods: We identified 1047 patients with GZL treated with CMT or chemotherapy alone between 2004 and 2016 from the National Cancer Database (NCDB). We excluded patients without histologic confirmation of the diagnosis, those who did not receive chemotherapy, and those who started chemotherapy >120 days or radiation >365 days from diagnosis to account for immortal time bias. Factors affecting treatment selection were investigated using a logistic regression model. A propensity score-matched methodology was used to compare survival outcomes.

Results: Only 164 patients (15.7%) received CMT, while 883 (84.3%) received chemotherapy alone. Treatment selection was affected by clinical factors (age, odds ratio [OR] 0.99, 95% confidence interval [CI] 0.98-0.997, p-value 0.01 and advanced stage, OR for stage 4: 0.21, 95% CI 0.13-0.34, p-value < 0.001) but not socioeconomic factors. Higher median income was associated with better survival, while increased age, higher comorbidity score, and B symptoms were associated with worse survival. The use of CMT had a survival advantage over chemotherapy alone (hazard ratio [HR] 0.54, 95% CI 0.351-0.833, p-value 0.005).

Conclusion: CMT is associated with survival advantage in our analysis. Careful selection of patients is essential to achieve the best outcomes with minimal toxicity. Socioeconomic factors affect treatment selection in patients with GZL that can alter outcomes. Future work should focus on strategies that access disparities without compromising survival.