This Trial is a Prospective Observational Study of Newly Diagnosed Diffuse Large B Cell Primary Breast Lymphomas

In this study, the investigators propose that the addition of rituximab will lower the risk of systemic and local relapses in patients with localized PBL. Patients will be treated with 6 cycles of RCHOP-14 or RCHOP-21. The administration of radiotherapy following chemotherapy is strongly recommended, based on the findings of the retrospective IELSG study, but will be at the discretion of the treating center.