Low-Dose Radiation Therapy in Treatment of Recalcitrant Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a benign, chronic inflammatory condition involving painful lesions that can progress to abscesses, skin tunnels, and fibrotic scars. Treatment of recalcitrant disease often involves immunomodulatory agents or surgery, but these often result in modest improvement. This study's objective was to determine the effectiveness of external beam low-dose radiation therapy (LD-RT) as an adjunct treatment for recalcitrant HS.

HS patients receiving LD-RT at a single institution from 2017 to 2024 were retrospectively identified. LD-RT dose included 750 cGy in 3 fractions or 800 cGy in 4 fractions. Patient demographics and comorbidities were recorded. Treatment response was categorized as excellent, partial, or no response, and site-specific symptoms were recorded based on available records.

Thirteen patients with HS underwent LD-RT to 38 sites were identified with a median follow-up period of 1.45 years from completion of LD-RT (range, 0.4-7 years). The majority of sites were Hurley stage III (34/38). At the patient level, all had been previously treated with antibiotics, 9 with prednisone, 12 with biologic agents, and 7 with a surgical procedure. Clinical response per site included 4 of 38 (10.5%) excellent, 26 of 38 (68.4%) partial, and 8 of 38 (21.1%) nonresponders. Four patients reported a reduction in pain score at first radiation oncology follow-up. For those with a response, median time from LD-RT to next rescue intervention was 2.2 months (range, 0.6-23.1 months). Three sites underwent surgery at a median time of 9.3 months from LD-RT completion. Two patients with 5 sites were retreated without response 1 year after LD-RT.

LD-RT for HS demonstrates high rates of response, with the majority of treated areas having some subjective improvement in disease burden, although most only have partial improvement. Need for rescue intervention shortly after this treatment is common.