P019: Unfavorable prognostic value of the predominance of THRLBCL-like histopathological growth patterns in nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL)

Abstract

Introduction: NLPHL is characterized by variable morphology and histopathological growth patterns of the tumor substrate. Our study demonstrated the prognostic significance of THRLBCL-like histopathological growth patterns. Purpose: to evaluate the efficacy of 1st line therapy of NLHLP depending on THRLBCL-like histopathological growth patterns in the tumor substrate. Materials and Methods: We analyzed the results of 1st line therapy in 150 patients with NLHLP from 2010 to 2021 yrs. Growth patterns without THRLBCL-like sites were noted in 87/150 (58%), THRLBCL-like patterns - in 63/150 (42%). Additionally, patients with a predominance of THRLBCL-like areas (more than 50% of the cut area) were identified - 32/150 (21%) pts. Results: In 87 (58%) pts with growth patterns without THRLBCL-like areas, 30/87 (34%) pts did not receive chemotherapy; radiation therapy was applied in 20/30 (complete remission (CR) was achieved in all 20 pts); observation after surgical treatment - 10/30 pts; 5 pts - no data. Chemotherapy (R-ABVD - 44%; R-BEACOPP-14–38%; other - 17% pts) was performed in 52/87 (60%) pts; CR was achieved in 68/87 (78%). In 63 (42%) pts with THRLBCL-like patterns, 2/63 (3%) did not receive chemotherapy; 1 patient - in CR after radiation therapy; 1 - under observation after surgical treatment; 4 patients - no data. Chemotherapy (R-ABVD - 18%; R-BEACOPP-14–54%; R-CHOP - 21%; other - 7% pts) received 57/63(90%) pts; CR was achieved in 31/63(49%) pts, partial remission (PR) - in 15/63(24%), stabilization (S) - 2(3%), progression - 4(6%) pts. In 32 (21%) pts with predominance of THRLBCL-like areas, 30 pts underwent chemotherapy (R-ABVD - 16%; R-BEACORP-14–57%; R-CHOP- 27% pts); CR was achieved in 12 (37%), PR-10 (31%), S-1 (3%), progression - 4 (13%) pts. In 2 pts - no data. The 5-year OS for groups with the absence, presence and predominance of THRLBCL-like patterns was 99%, 100%, 68% (p-<0.0001), respectively, the 5-year EFS was 75%, 68%, 32% (p-< 0.0001) respectively. Median follow-up is 34 months. Conclusion: In NLHLP the group of patients with a predominance of THRLBCL-like patterns has the most unfavorable prognosis - CR achieved in 37%, 5-year OS does not exceed 68%, EFS - 32%. Therefore an intensification of first-line therapy is needed for this group of patients.