Treatment outcomes between cyclosporin and chemotherapy in adult subcutaneous panniculitis-like T-cell lymphoma: a report from nation-wide Thai lymphoma study group registry.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare subtype of T-cell lymphomas with a characteristic feature of subcutaneous nodules associated with hemophagocytic lymphohistiocytosis (HLH). Treatment options for SPTCL are mainly chemotherapy (CMT) or immunosuppressive agents with selection currently dependent on physician decisions. Outcomes between the 2 treatment remedies have not yet been comprehensively compared. This study aimed to compare complete remission (CR) rates between SPTCL patients receiving cyclosporin (CSA)-based regimen (CSA +/- steroid) and CMT. The 5-year overall survival (OS) and 5-year progression free survival (PFS) were also analyzed. Clinical data from patients with SPTCL were drawn from the Thai Lymphoma Study Group registry who were newly diagnosed between 2007 and 2023. A total of 93 patients were selected with 45 cases having received CSA-based regimen and 48 cases having received CMT. There were more patients with limited stage at skin in the CSA group (63.8% vs. 36.2%, p = 0.003), while more patients with hepato- and/or splenomegaly were found in the CMT group (56.2% vs. 24.5%; p = 0.002). Germline HAVCR2 mutations were detected in 26/33 (78.8%) cases. The CR rate was significantly higher in patients treated with CSA (87% vs. 58.3%; OR = 6.5 [95%CI, 2.7-15.3]; p = 0.002). At a median follow-up of 87.8 months (range 0-185), the 5-year OS (98% vs. 87%, p = 0.19) and PFS (72.4% vs. 69.2%, p = 0.19) showed a trend favoring patients treated with CSA. Based on our study, CSA-based regimens are the preferred first-line treatment remedy for newly diagnosed SPTCL, especially in patients with limited cutaneous involvement.