Clinical presentation, outcome, and prognostic markers in patients with intravascular large B‐cell lymphoma, a lymphoma study association (LYSA) retrospective study

BACKGROUND: Intravascular large B‐cell lymphoma (lVLBCL) is a very rare type of large B‐cell lymphoma. METHODS: We conducted a retrospective study on IVLBCL patients treated from 2000 to 2016 in LYSA cooperative group centers. RESULTS: Sixty‐five patients were identified in 23 centers. Median age at diagnosis was 69 years (range 23–92). Thirty‐four patients (64%) had an IPI score >3 and 40 patients (67%) had a performance status ≥2. The most frequent extra‐nodal locations were bone marrow (n = 34; 52%), central nervous system (n = 25; 39%), and skin (n = 21; 33%). Nodal involvement and endocrine system were observed in 34% (n = 22) and 18% (n = 12) of all cases, respectively. Twenty‐six patients (41%) had macrophage activation syndrome. Tumor cells were frequently CD5 positive (52%) with a non‐germinal center origin (86%). BCL2 was expressed in 87% of all samples analyzed (n = 20) and 43% of patients had a MYC/BCL2 double expression. Fifty‐six patients were treated with a regimen of chemotherapy containing rituximab, among whom 73% reached complete remission. The median progression‐free survival (PFS) and median overall survival (OS) were 29.4 months and 63.8 months, respectively. History of autoimmune disorder (Hazard ratio [HR] 3.3 [1.4–7.8]; p < 0.01), nodal involvement (HR 2.6 [1.4–5.1]; p < 0.01), lack of anthracycline (HR 0.1 [0–0.4] for use; p < 0.001), or no intensification at first‐line regimen (p = 0.02) were associated with worse PFS. High‐dose methotrexate use was not associated with better PFS or OS. CONCLUSIONS: Our study highlights the aggressive clinical picture of IVLBCL, in particular the frequency of macrophage activation syndrome, and the need for new therapies despite a response to R‐CHOP‐like regimen similar to non‐intravascular diffuse large B‐cell lymphomas.