Association of prophylactic G-CSF use with survival outcomes in patients with aggressive B-cell lymphomas treated with R-CHOP.

e19061 Background: R-CHOP is the standard first-line regimen for aggressive CD20-positive B-cell lymphomas, including diffuse large B-cell lymphoma. Outcomes depend on maintaining chemotherapy dose intensity, but myelosuppression and febrile neutropenia (FN) frequently lead to treatment delays or dose reductions. Prophylactic granulocyte colony-stimulating factors (G-CSFs) reduce FN risk and preserve dose intensity and are guideline-recommended for patients at moderate-to-high FN risk; however, evidence for improved long-term survival in real-world R-CHOP–treated populations remain limited. We evaluated the association between prophylactic G-CSF use and survival and safety outcomes using a multi-institutional electronic health record network. Methods: We conducted a retrospective study using the TriNetX research network from 2012-2024. Adults with aggressive B-cell lymphomas who received R-CHOP were grouped based on whether or not they received prophylactic G-CSF within 3-days of cycle 1. Propensity score matching was used to balance cohorts before comparing survival using a Kaplan-Meier survival analysis. Secondary outcomes included early neutropenia and septic shock or vasopressor use. Results: After propensity score matching, 4,007 patients receiving R-CHOP with G-CSF were well balanced with 4,007 patients receiving R-CHOP without G-CSF across baseline characteristics. At 6 months, mortality was 6.20% with G-CSF versus 7.33% without (risk difference −1.13%, 95% CI −2.23% to −0.02%; HR 0.84, 95% CI 0.71–0.99; p = 0.045). At 12 months, mortality was 10.20% vs 11.42% (risk difference −1.22%, 95% CI −2.58% to 0.15%; HR 0.88, 95% CI 0.77–1.00; p = 0.08), and at 24 months remained lower with G-CSF (13.48% vs 15.10%; risk difference −1.63%, 95% CI −3.16% to −0.09%; HR 0.87, 95% CI 0.78–0.98; p = 0.038). Survival probabilities favored G-CSF at 6 months (93.7% vs 92.5%), 12 months (89.4% vs 88.1%), and 24 months (85.6% vs 83.7%). Neutropenia was more frequently documented with G-CSF (28.7% vs 26.7%; HR 1.13, 95% CI 1.04–1.23; p < 0.001) but not after excluding patients with prior neutropenia (22.45% vs 23.03%; HR 1.02, 95% CI 0.93–1.13; p = 0.56). Rates of septic shock (1.20% vs 1.22%; HR 0.98, 95% CI 0.66–1.46; p = 0.91) and septic shock or vasopressor use were low and similar between groups, including in sensitivity analyses. Conclusions: In this large real-world, propensity-matched cohort of patients with B-cell lymphomas treated with R-CHOP, prophylactic G-CSF use was associated with improved early and long-term survival without a difference in septic shock or severe infectious complications. Apparent increases in neutropenia were not observed after accounting for baseline history, suggesting no excess risk of new-onset neutropenia. These findings support the routine use of G-CSF with R-CHOP and suggest a potential survival benefit beyond neutropenia prevention.