Clinical and treatment-related features determining the risk of late relapse in patients with diffuse large B-cell lymphoma.

It is still unclear whether there are clinically exploitable differences in the biology and behaviour of early versus late relapses in diffuse large B-cell lymphoma (DLBCL). The present study aimed to analyse a large population-based DLBCL cohort in order to identify (i) the frequency of late relapses (LR), (ii) parameters influencing the risk of LR, and (iii) the impact of introducing rituximab on the occurrence of LR. The data of 7247 DLBCL patients was obtained from the Danish Lymphoma Group Registry. Patients with LR had a lower International Prognostic Index and better performance score than early relapse (ER) patients. The use of radiotherapy lowered only the rate of ER while the use of rituximab yielded a lower occurrence of both ER and LR (P < 0·0001 and P < 0·0001, respectively), possibly suggesting a longer-lasting biological effect. Additionally, we found a female overrepresentation among LR patients that had received a rituximab-containing first line treatment. It was found that patients with LR had a significantly better 5-year overall survival compared to ER patients. In conclusion, LR was more frequently associated with low-risk features than ER. Furthermore, we found that the use of modern immunochemotherapy regimens in DLBCL lowers the risk of both ER and LR.