Abstract 3833: Primary cutaneous diffuse large B-cell lymphoma-leg type and clinicopathologic determinants of survival: Analysis of a pooled database

Abstract Background: Primary Cutaneous Diffuse Large B-cell Lymphoma-Leg Type (PCDLBCL-LT) is a rare but non-indolent subtype of B-cell lymphoma. While most PCDLBCL-LT starts over the lower extremities, some cases may present at other cutaneous sites. The determinants of survival outcomes in this disease are not very well defined. Therefore, we conducted this pooled database analysis to identify the prognostic factors, clinicopathological characteristics, and therapeutic strategies that influence survival in this disease. Methods: To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 122 cases that fit the diagnostic criteria for PCDLBCL-LT. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS) and disease-free survival (DFS). Results: A total of 122 patients with confirmed PCDLBCL-LT were identified. The median age was 76. There was a male preponderance with M: F of 2. 4. Seventy-three percent involved the extremities. The median duration of symptoms before diagnosis was 3. 5 months. Involvement of lymph nodes, bone marrow, bone, and CNS occurred in 11%, 3%, 4%, and 3%, respectively. Constitutional symptoms were reported in 5%. The median OS and DFS of the whole group were 39 and 32 months, respectively. Patients younger than 70 had better median DFS (NR vs. 24 months, p=0. 02) with a non-significant better median OS. Lymphadenopathy (45 vs. 18 months, p=0. 006) and stage T3 compared to T1/T2 (16 vs 41 months, p=0. 006) were associated with worse OS. Sex, constitutional symptoms, IHC phenotype, extra-lymphatic/extra-cutaneous organ involvement, and histologic cutaneous patterns did not impact OS. Compared to no treatment, chemotherapy, XRT+/-surgery, and stem cell transplant had numerically better OS without reaching statistical significance (5 vs. 39 vs. 41 vs. NR months, p=0. 15). Patients who attained CR as their best response also had a superior median OS compared to responses less than CR and none (61 vs. 23 vs. 11 months, p0. 0001). Conclusion: This study presents updated clinicopathologic data from a large, pooled cohort of patients with PCDLBCL-LT. It identifies age, lymph node involvement, T stage, type of therapy, and quality of response to treatment as critical determinants of OS. Citation Format: Philip A. Haddad, Millicent Amankwah. Primary cutaneous diffuse large B-cell lymphoma-leg type and clinicopathologic determinants of survival: Analysis of a pooled database abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 3833.