ABCL-398 Primary Breast Diffuse Large B-Cell Lymphoma: An Indian Experience

Abstract

Primary breast diffuse large B-cell lymphoma (PB-DLBCL) is a rare site of localized extranodal DLBCL. It represents 0.5% of all primary malignant neoplasms of the breast and around 2% of extranodal lymphomas. There is a paucity of data regarding the clinicopathologic characteristics, cell of origin, response, and outcome of treatment with uniform treatment protocol in patients from India diagnosed with PB-DLBCL. This was a retrospective study of 18 consecutive cases of PB-DLBCL registered at All India Institute of Medical Sciences between 2006 and 2021 treated with uniform 3x weekly cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) ±rituximab (R) with involved-field radiotherapy. The patients were classified as germinal center B-cell-like or activated B-cell (ABC) type using the Hans classification. The median age was 43 (21-67) years with a male:female ratio of 1:17. All the patients presented with a breast lump with a median tumor size of 5 cm. The right side was involved in 11 (61.1%) cases. Eight patients were diagnosed with lumpectomy, 9 patients with biopsy, and one patient with mastectomy specimen. Out of 18 patients, Ann Arbor: Stage I was seen in 6 (33.3%) patients, Stage IIE in 11 (61.1%) patients, and Stage 1V in 1 (5.5%) patient. B-symptoms and bulky disease were seen in 6 (33.3%) and 7 (38.8%) patients, respectively. Cell of origin data were available in 14 patients, and 11 (71.4%) were ABC in origin. Low- and intermediate-risk International Prognostic Index was seen in 42% and 48% of patients, respectively. The median number of chemotherapy cycles was 4 (3-6), rituximab was used in 10 (55.5%) cases, and CNS prophylaxis with intrathecal methotrexate was used in 10 (55.5%) cases. The complete response rate was 83.3%. After a median follow-up of 42 months, the 3-year progression-free survival and overall survival were 75% and 88%, respectively. The most common site of relapse (n=3) was parenchymal brain disease. Multimodality combination therapy (chemotherapy, immunotherapy, and radiation) can give good survival with PB-DLBCL but adding high-dose methotrexate to existing protocol needs further exploration.