Outcomes in primary cutaneous diffuse large B-cell lymphoma, leg type.

Area of Science:

• Hematology
• Dermatology
• Oncology

Background:

• Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL, LT) is a rare and aggressive skin lymphoma.
• Over-expression of PD-L1/PD-L2 is common in PCDLBCL, LT, suggesting potential for immune checkpoint inhibitors (ICI).
• The efficacy of ICI in relapsed/refractory PCDLBCL, LT remains understudied.

Purpose of the Study:

• To evaluate the efficacy of front-line immunochemotherapy with or without involved-site radiation therapy (ISRT) for PCDLBCL, LT.
• To assess the outcomes of salvage immune checkpoint inhibitor (ICI) therapy in patients with relapsed/refractory PCDLBCL, LT.

Main Methods:

• Retrospective cohort study of 28 patients diagnosed with PCDLBCL, LT from 2000-2020.
• Kaplan-Meier method used to calculate progression-free survival (PFS), duration of response (DOR), and overall survival.
• Comparison of outcomes for patients receiving front-line R-CHOP with or without ISRT, and those treated with salvage ICI therapy.

Main Results:

• Patients treated with R-CHOP plus ISRT had a significantly longer median PFS (58 months) compared to R-CHOP without ISRT (14 months; p=0.04).
• Salvage ICI therapy showed a median PFS of 10 months and a median DOR of 23 months in heavily pre-treated patients.
• R-CHOP with ISRT demonstrated superior front-line efficacy for PCDLBCL, LT compared to R-CHOP alone.

Conclusions:

• Involved-site radiation therapy (ISRT) combined with R-CHOP improves progression-free survival in primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL, LT).
• Immune checkpoint inhibitors (ICI) represent a viable treatment option for relapsed/refractory PCDLBCL, LT, showing reasonable activity.
• Further research into ICI efficacy in PCDLBCL, LT is warranted.