Photodynamic Therapy with 3-(1'-hexyloxyethyl) pyropheophorbide a (HPPH) for Cancer of the Oral Cavity
Menée sur 40 patients présentant une dysplasie de la cavité buccale, un carcinome in situ ou un carcinome épidermoïde de la tête et du cou de stade précoce (durée de suivi : 5 à 40 mois), cette étude évalue l'efficacité, du point de vue de la réponse tumorale à 3 mois, et la sécurité d'une thérapie photodynamique à base d'un composé appelé HPPH
Purpose : The primary objective was to evaluate safety of 3-(1'-hexyloxyethyl)pyropheophorbide-a (HPPH) photodynamic therapy (HPPH-PDT) for dysplasia and early squamous cell carcinoma of the head and neck (HNSCC). Secondary objectives were the assessment of treatment response and reporters for an effective PDT reaction. Experimental Design : Patients with histologically proven oral dysplasia, carcinoma in situ (CiS ) or early stage HNSCC were enrolled in two sequentially conducted dose escalation studies with an expanded cohort at the highest dose level. These studies employed an HPPH dose of 4 mg/m2 and light doses from 50 to 140 J/cm2. Pathologic tumor responses were assessed at 3 months. Clinical follow up range was 5 to 40 months. PDT induced cross-linking of signal transducer and activator of transcription 3 (STAT3) were assessed as potential indicators of PDT effective reaction. Results : Forty patients received HPPH-PDT. Common adverse events were pain and treatment site edema. Biopsy proven complete response rates were 46% for dysplasia and CiS, and 82% for SCCs lesions at 140 J/cm2. The responses in the CiS/dysplasia cohort are not durable. The PDT induced STAT3 cross-links is significantly higher (P=0.0033) in SCC than in CiS/dysplasia for all light-doses. Conclusion : HPPH-PDT is safe for the treatment of CiS/dysplasia and early stage cancer of the oral cavity. Early stage oral HNSCC appears to respond better to HPPH-PDT in comparison to premalignant lesions. The degree of STAT3 cross-linking is a significant reporter to evaluate HPPH-PDT mediated photoreaction.