Clinical Characteristics and Outcomes of Primary Breast Lymphoma: The Cleveland Clinic Experience.

Introduction Primary breast lymphoma (PBL) is a rare malignancy that accounts for less than 0.5% of all breast malignancies. Materials and Methods We retrospectively analyzed 36 PBL patients to report the clinical characteristics and outcomes of patients with indolent and aggressive histologic subtypes. Results Thirteen (36%) patients had aggressive and 23 (64%) had indolent PBL. Marginal zone lymphoma was the most common histologic subtype (33%). Stage IE, IIE, and IV disease were seen in 27 (75%), six (17%), and three (8%) patients, respectively. Patients with aggressive PBL more often presented with a breast lump and/or B symptoms (unexplained weight loss, fever, night sweats) (78% vs. 31%, p = 0.005). Commonly used treatment modalities for aggressive vs. indolent PBL were chemotherapy alone (23% vs. 26%, p = 0.8), chemoradiotherapy (46% vs. 9%, p = 0.009), radiotherapy alone (15% vs. 22%, p = 0.6), and observation (0% vs. 26%, p = 0.07), respectively. The five-year overall survival (OS) and progression-free survival (PFS) of PBL patients were 82% (95% CI: 67 - 100) and 63% (95% CI: 45 - 89), respectively. The five-year OS of patients with aggressive vs. indolent PBL were 92% (95% CI: 77 - 100) vs. 80% (95% CI: 63 - 100), respectively (p = 0.6). The five-year OS of patients who received > 1, 1, and 0 treatment modalities were 92% (95% CI: 77 - 100), 86% (95% CI: 63 - 100), and 53% (95% CI: 21 - 100), respectively. Conclusion In our cohort, the higher utilization of chemoradiotherapy in aggressive PBL was able to overcome the worse prognosis of these patients. At least one treatment modality should be considered in patients with indolent PBL, given that observation alone was associated with a poor prognosis.