Electrochemotherapy of unresectable cutaneous tumours with reduced dosages of intravenous bleomycin: analysis of 57 patients from the International Network for Sharing Practices of Electrochemotherapy registry.

Background: Electrochemotherapy (ECT) is currently used to treat unresectable superficial tumours of different histotypes through the combination of cytotoxic chemotherapy and local application of electric pulses. In 2006, a collaborative project defined the ESOPE (European Standard Operating Procedures of Electrochemotherapy) guidelines to standardize the procedure. The International Network for Sharing Practices of Electrochemotherapy (InspECT) aims to refine the ESOPE and improve clinical practice. Limiting patient exposure to systemic chemotherapy would be advisable to ameliorate ECT safety profile.

Objective: The aim of this study was to evaluate the efficacy and toxicity of ECT with reduced chemotherapy dosages.

Methods: In a retrospective analysis of a prospectively maintained database (InspECT registry), we evaluated the outcome of patients who received ECT with reduced dosages of bleomycin (7500, 10 000 or 13 500 IU/m , instead of the standard dose of 15 000 IU/m ). Tumour response in melanoma patients was compared with melanoma patients of the InspECT registry who received the standard dose of bleomycin.

Results: We identified 57 patients with 147 tumours (melanoma, 38.6%; squamous cell carcinoma, 22.8%; basal cell carcinoma, 17.5%; breast cancer 7%; Kaposi sarcoma 7%; other histotypes, 7.1%). Per-tumour complete response (CR) rate at 60 days was 70.1% (partial, 16.3%); per-patient CR was 57.9% (partial, 21.1%). Local pain was the most frequently reported side-effect (n = 22 patients [39%]), mostly mild; two patients experienced flu-like symptoms, one patient nausea. We observed the same CR rate (55%) in patients with melanoma treated by reduced or conventional bleomycin dosages (P = 1.00).

Conclusions: Electrochemotherapy performed with reduced bleomycin dosages could be as effective as with currently recommended dose. Patients with impaired renal function or candidate to multiple ECT cycles could benefit from a reduced dose protocol. Our findings need prospective confirmation before being adopted in clinical practice.