ANTHRAPYRAZOLES AND INTERSTITIAL LASER PHOTOTHERAPY FOR EXPERIMENTAL TREATMENT OF SQUAMOUS-CELL CARCINOMA

Interstitial laser therapy (ILT) is an effective palliative treatment for advanced head and neck cancer, but recurrence often is seen at the margin. The objective of the current study was to test combined drug and laser therapy as an experimental approach for improved treatment o f human squamous cell carcinoma (SCCA). Human SCCA tumor transplants w ere grown in nude mice and injected with the photosensitive anthrapyra zole CI-941 before ILT. Intralesional drug injections alone at levels ranging from 60 to 1200 mu g/gm of tumor induced a growth delay at the higher doses, but recurrence was seen in all 35 tumors tested. SCCA t umor transplants injected with 240 mu g/gm CI-941 followed after 4 hou rs by ILT with the KTP532 laser led to a complete response rate of 72% (21/29) compared with 45% (13/29) for ILT alone. Laser chemotherapy w as a significant improvement compared with ILT when partial and comple te responses were combined (P < 0.03). The results provide preclinical evidence that laser chemotherapy may become a useful minimally invasi ve treatment for advanced squamous cell carcinoma of the head and neck .