Electroporation therapy for head and neck cancer including carotid artery involvement

Electroporation therapy with intralesional bleomycin (EPT) is a novel, technically simple outpatient technique in which high-voltage electric impulses delivered into a neoplasm transiently increase cell membrane permeability to large molecules, including cytotoxic agents, causing localized progressive necrosis. Unlike many laser ablation methods, EPT can treat bulky tumors (>2 cm) with complete penetration. Our recent publication confirms an excellent response rate in the use of EPT in a clinical trial.

Following our initial prospective study report in 1998, we have followed our entire initial cohort (10 patients) of patients with head and neck cancer beyond 24-months follow-up. Additionally, we have used this approach to treat four additional patients (total: 9 males/5 females) with upper aerodigestive tract squamous cell carcinoma, including three with internal carotid artery (ICA) involvement up to or within the skull base. Two patients underwent preoperative balloon test occlusion with cerebral perfusion studies followed by carotid embolization. EPT was then done safely at least 2 weeks later to avoid the temporary hypercoagulable state.

Within the overall cohort (14 patients) 6 patients had a complete response, 6 had a partial response, and 2 did not respond (overall 85.7% response rate). Both patients with ICA involvement had a partial or complete response to treatment; neither patient had a hemorrhagic or neurologic complication. Overall, 13 of the 14 patients were treated for persistent or recurrent head and neck cancer. Two of the four patients with early recurrent stage tumors had no evidence of recurrence after EPT with an average follow-up of 31.5 months. The overall early stage tumor group had four complete responders out of five (80%). On the contrary, only 2 of 9 patients with advanced recurrent stage tumors were disease-free at 18 months. Morbidity was low for early stage tumors, but higher for advanced tumors with complications, including poor wound healing, dysphagia, and osteomyelitis. There were no treatment-related deaths.

We found EPT to be safe and efficacious in patients with head and neck cancer, even with internal carotid artery involvement. Patients with early stage recurrences have the potential for prolonged survival beyond 2 years without the morbidity of surgery and radiation or toxicity of systemic chemotherapy. Because of its superb access qualities even for bulky tumors, EPT is a potential method of delivery for other tumoricidal agents such as in genetic-altering schemes.