Bulky disease has an impact on outcomes in primary diffuse large B-cell lymphoma of the breast: A retrospective analysis at a single institution

Objectives: Primary breast lymphoma (PBL) is rare, and its clinical behavior and standard initial treatment are not yet established. Methods: We retrospectively analyzed the clinicopathological features and treatment outcomes of 14 patients with primary breast diffuse large B-cell lymphoma. Results: There were nine patients with stage IE and five with stage IIE disease. The median largest tumor diameter was 4.5cm, and five patients had bulky disease >5cm. The complete response rate was 94%. However, the 5-year progression-free survival rate was 52% with a median follow-up of 5.2years. Patients with bulky disease had an unfavorable prognosis. All five patients with bulky disease progressed or relapsed. Of the four patients that recurred in the central nervous system (CNS), three had bulky disease although some received rituximab. There were no CNS recurrences in the three patients who received CNS prophylaxis. All eight patients who responded to radiotherapy (RT) did not have recurrences in the ipsilateral breast, although one patient with bulky disease relapsed in the adjacent regional lymph nodes within the RT field despite immunochemotherapy. Conclusions: Patients with bulky disease had a poorer prognosis and recurred frequently in the CNS. CNS prophylaxis might yield better outcomes, but a larger, prospective trial is needed to elucidate the optimal initial treatment of PBL in the rituximab era.