PHOTODYNAMIC THERAPY OF MALIGNANT AND PREMALIGNANT LESIONS IN PATIENTS WITH FIELD CANCERIZATION OF THE ORAL CAVITY

The management of patients with 'field cancerization' of the oral muco sa. with multicentric foci of invasion, presents a considerable proble m for the head and neck surgeon. Surgical resection of synchronous or metachronous primary squamous cell carcinomas, along with adjacent pre malignant lesions, is likely to be associated with considerable mutila tion. Photodynamic therapy (PDT) has been shown to be of value in the treatment of superficial tumours in the upper aerodigestive tract, wit h excellent healing of treated areas. This study reports the use of PD T to treat 11 patients with 'field cancerization' occurring in the ora l cavity. Six 'patients had multiple primary cancers and five had sing le primary tumours. All had associated areas of leukoplakia. Each rece ived Photofrin 2 mg/kg 48 hours prior to photoirradiation with 50-100 J/cm2 red laser light by surface illumination. Six to eight weeks late r treated areas in 10 of the 11 patients showed a complete response to PDT; one patient had areas of residual leukoplakia. Two patients deve loped further areas of leukoplakia or erythroplakia within 12 months b ut no patient has had evidence of recurrent invasive carcinoma in the treated areas. Longer term follow-up will be necessary to exclude furt her recurrence. It is concluded that PDT offers an effective repeatabl e treatment option, whether on its own or as an adjunct to local excis ion, for patients with 'field cancerization' of the oral cavity.