Interstitial photodynamic therapy for a symptom-targeted treatment of complex vascular malformations in the head and neck region

Photodynamic therapy is based on an interaction of a drug and light in oxygenated tissue. The photosensitizing drug Foscan is licensed in the EU for the treatment of advanced head and neck cancer. The light can be applied by surface illumination or directly into tumour tissue by optical fibres. One interesting feature of PDT is that it does not cause major damage to nerves and major blood vessels. This raises the possibility of using this therapy in the treatment of benign neoplasms in the head and neck.

A total of 11 patients with lymphatic [8] or venous malformation [3] were treated on 25 occasions. The treatments were carried out using Temoporphin (Foscan) 0.15 mg/kg; the drug-light-interval was 4 days. Illumination was performed at 652 nm delivered interstitially through bare tip fibres at a total light dose of 20 J per fibre. Multiple fibres were positioned either image guided [13] or clinically [12] to ensure accurate targeting of tissue while avoiding damage of the surrounding and overlying tissue.

In all cases there was a significant reduction in the volume of abnormal tissue without damage to the overlying skin; the results were objectified using MRI-imaging, CT-volumetry and surface optical scanning. The best results were obtained with lymphatic malformations, especially for those that had not undergone previous surgery. Post-treatment pain and swelling were successfully controlled with steroids and a variety of analgesics (opioids and non-steroidal anti-inflammatories). No vascular or neurological signs were encountered.

This minimally invasive approach to treat complex benign neoplasias seems promising. The treatment is safe, effective and repeatable and merits further evaluation.