mTHPC-mediated photodynamic therapy for early oral squamous cell carcinoma

Abstract

Surgery and radiotherapy are standard treatments for early oral squamous cell carcinoma, both resulting in good tumour control. However, neither of these modalities is without consequent functional or cosmetic impairment, and there are patients in whom both are contraindicated. Furthermore, there is a significant risk of metachronous tumours developing in the oral cavity, and salvage or retreatment with either surgery or radiotherapy poses difficulties. Photodynamic therapy (PDT) offers the potential for improved functional and cosmetic outcomes, while achieving comparable tumour control. We conducted an open-label, multicentre study to assess the efficacy and safety of meta-tetrahydroxyphenylchlorin (mTHPC) in patients with early oral cancer. One hundred twenty-one patients received intravenously administered mTHPC, followed 96 hr later by illumination of the tumour surface with 652 nm laser light. Of these patients, 114 were protocol compliant. A complete tumour response was achieved in 85% of protocol-compliant patients (97 of 114 patients). A complete response was maintained in 85% of responders at 1 year and in 77% at 2 years. One- and 2-year actuarial survival rates were 89% and 75%, respectively. In the opinion of the investigators, tumour clearance was accompanied by excellent cosmetic and functional results, without impact on the patients' performance status. Mild-to-moderate pain at the treatment site, a recognised side effect of PDT in the oral cavity, was reported by 82% of patients but was manageable with appropriate analgesia. Mild-to-moderate skin photosensitivity reactions were reported for 13% of patients. mTHPC offers an effective alternative treatment for early oral squamous cell carcinoma. It is associated with excellent functional and cosmetic results and can be used in conjunction with other standard therapies.