Radiotherapy in the Treatment of Primary Cutaneous CD4+ Small/Medium T-Cell Lymphoproliferative Disorder

Abstract

<h3>Purpose/Objective(s)</h3> Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSM-LPD) is a rare disorder, typically presenting in adults as a solitary lesion in the head and neck. Data describing the role of radiotherapy (RT) in the management of PCSM-LPD are limited. <h3>Materials/Methods</h3> We retrospectively reviewed 46 patients (pts) with PCSM-LPD confirmed at our institution from 2/1/2009-11/30/2021. Clinical/treatment characteristics, response, and toxicity (CTCAE v5.0) were extracted from the medical records. Statistics were performed using Mann-Whitney U and Chi-square tests. <h3>Results</h3> The median age at diagnosis was 57 years (interquartile range (IQR) 43-67)) and 22 (48%) were female. 38 pts (83%) presented with a solitary lesion. Of 57 biopsied lesions, 28 (49%) were located in the head and neck, 19 (33%) were on the trunk, and 10 (18%) were on the upper extremities. 36 pts (78%) had systemic staging with PET/CT or CT; 8 pts (17%) underwent bone marrow examination. Histologic evaluation showed an atypical, polymorphous, lymphocytic infiltrate involving the dermis, with unequivocal epidermotropism in 2 pts (4%), and minimal/focal epidermotropism in an additional 19 pts (41%). Immunohistochemical analysis showed that all cases were positive for CD4 (n=46) and CD3 (n=45 assessed). CD7 was positive in 26 (57%), PD1 in 25 (54%), and CD5 in 24 (52%) cases. CD4:CD8 ratio was available in 20 pts, with a median of 5 (IQR 4-8). Monoclonal T-cell receptor beta/gamma rearrangements were present in 38 of 41 pts (93%) assessed. Of 44 evaluable pts, management following diagnostic biopsy included observation (16, 36%), steroid (12, 27%), steroid and RT (8, 18%), and RT (7, 16%). One additional pt achieved CR after biopsy following a course of antibiotics for bronchitis. With median follow-up of 16 months (IQR 4-85 months), pts with residual lesions after biopsy achieved CR with steroids (12/19, 63%) or RT (12/14, 86%) (p = 0.007). Seven RT pts received prior steroid with incomplete response. One pt received intralesional steroids after RT with a CR, and one pt is in partial response one month post-RT. RT was given with electrons (12, 80%) or orthovoltage (3, 20%). The median dose was 4 Gy in 2 fractions (range 4-30 Gy in 1-15 fractions); 10 pts received 4 Gy. Four pts (27%) developed a grade 1 skin reaction following RT (3 erythema, 1 itching). There was no difference in response based on RT dose (p = 0.28), RT modality (p = 0.45), or steroid use prior to RT (p = 0.92). Prescribed doses decreased after reclassification of the diagnosis from lymphoma to LPD in 2016, median 12 Gy (IQR 6-30) vs. 4 Gy (IQR 4-4) (p = 0.002). Of 36 pts with sufficient follow-up, recurrence (all out of field) occurred in 4 (11%), more commonly in pts with multiple lesions at diagnosis (3/7 vs. 1/29, p = 0.02). <h3>Conclusion</h3> PCSM-LPD has an indolent course and responds well to low-dose RT. Treatment should be guided by a multidisciplinary team.