An overview of the correlation between IPI and prognosis in primary breast lymphoma

Primary breast lymphoma (PBL), with diffuse large B-cell lymphoma (DLBCL) as the most histopathological type, is a rare disease with a poor prognosis. The International Prognostic Index (IPI) is an important clinical characteristic for risk stratification of PBL patients with different prognoses. However, the prognostic value of the IPI in PBL is controversial and needs to be refined. In this review, we described the clinical characteristics, pathogenesis, and treatment of PBL, with emphasis on the prognostic value of the IPI, its updated versions and IPIs for certain subtypes. A total of 9 types of IPIs were presented. In addition, the key issues with the various treatment modalities available were addressed, as well as the role of rituximab in therapy. We also summarized the current evidence and future challenges facing other types of prognostic indices. In particular, prospective clinical studies of treatment are rare, and the available data were mainly obtained from retrospective case series that included a small number of patients. Therefore, our conclusions and recommendations cannot serve as formal guidelines. However, this review attempts to provide an unbiased analysis of published data to provide clinicians with useful assistance in the treatment of this uncommon form of extranodal lymphoma.