DDIT3 and diffuse large B-cell lymphoma: After pegfilgrastim approval, the RDI of R-CHOP was able to be maintained at higher levels, the incidence of FN was lower, and significantly better clinical outcomes were achieved in clinically high-risk groups, suggesting that maintaining a high RDI in R-CHOP by administering pegfilgrastim to those who need it to keep the RDI at a high level is important for achieving favorable outcomes in patients with DLBCL.