Efficacy and safety of HpD-PDT for Extramammary Paget's Disease refractory to conventional therapy: A prospective, open-label and single arm pilot study

Extramammary Paget's Disease (EMPD) is an intraepithelial cancer that is prone to recurrence and sometimes refractory to therapy. A few EMPD cases have been treated with Photodynamic therapy (PDT), which reported high complete remission (CR) rates and low recurrence with hematoporphyrin derivatives (HpD) The aim of this study was to further explore the efficacy and safety of HpD-PDT for EMPD patients.Open-label, single arm, pilot study was designed to investigate the role of HpD-PDT in EMPD. The HpD sensitizer was given intravenously at a dose of 3 or 5 mg/kg 48 h before light irradiation with a laser 630 nm red light at a dose level of 150-200 J/cm2. Clinical parameters involving gender, age, disease course, previous treatment, tumor thickness, long diameter of lesion, TNM staging, EMPD staging, HpD dosage, Visual Analogue Scale (VAS) score, 1st month visit result, subsequent treatment, follow up period and endpoint outcomes were collected to evaluate efficacy and safety of the intervention.Eleven patients with pathologic confirmed EMPD were treated with HpD-PDT. The thickness of skin lesions which were located in vulva, penis, scrotum, and perianal area is 0.8∼6.7 mm (mean thickness 2.9 mm). All patients were followed up for an average of 17.4 months (12∼27 months). Complete remission (CR) rate and partial remission (PR) rate at the 1st month were 90.1% (10/11) and 9.1% (1/11) respectively. At the end of follow-up, 72.7% of the subjects (8/11) showed CR. Pain, infection, photosensitivity and uroschesis are recorded as adverse events (AEs) in this population, and no event of hepatic impairment was reported. After treatment, all the eleven patients showed different degrees of scar in the treatment site, but none of them had any structural or functional abnormalities.According to our study, HpD-PDT in EMPD is able to offer acceptable disease outcomes including relatively high CR rate, with good cosmetic and functional outcomes, and could be considered a potential recommended therapy for patients with EMPD.Chinese Clinical Trial Register (ChiCTR-1900024965).