Long-Term Follow-Up after Radiotherapy of Hidradenitis Suppurativa.

Background: Patients with hidradenitis suppurativa (HS) are still often disappointed with the current treatments offered and there is a clear demand for more effective options. Since the late 1990s there has been a revival in the use of radiotherapy (RT) for different benign diseases, including HS. During the past 20 years one case series and some scattered case reports have described promising results of RT.

Objectives: To evaluate the long-term efficacy of RT in early-stage HS.

Methods: A postal survey-based long-term follow-up with simple factual questions of partly retrospective and partly contemporary characteristics was performed. Sixty-four patients (96 axillae), diagnosed with mild to moderate HS were irradiated with a orthovoltage unit with 100 kV, 3 mm Al or 200 kV, 0.5 Cu filtering, respectively. Four to six biweekly fractional doses ranging from 0.75 to 1 Gy up to a total dose of 6 Gy in one series, and in chronic cases followed by four daily fractions of 2 Gy up to a total dose of 14 Gy, were given. Late treatment toxicity and the rate of remission of the disease were evaluated.

Results: The overall response rate of the survey was 64.1% with 40.6% (26/64) valid, complete questionnaires. In total, 40 axillae were irradiated in these 26 patients. After a median follow-up of 40 years (range 32-52) complete remission of the lesions occurred in 34 of the 40 sites (85%). None of the 26 patients with 40 irradiated sites reported adverse effects at the time of the survey.

Conclusions: RT appears to be an effective treatment for early and mild HS in the majority of patients. In this case series, no side effects were reported after a median follow-up period of 40 years.