Laser photoradiation therapy of cancer: An update of the experience at the university of California, Irvine

This update of the experience at the University of California at Irvine with laser photoradiation therapy (PRT) encompasses the period between May 1981 and June 1983. The results of treatment of 77 patients are reported (head and neck, 39; breast, 33, and lung 5). Head and neck cancer patients received treatment to 114 sites with a complete response (CR) in 28, partial response (PR) in 42, stable disease (SD) in three, and no response (NR) in 34, and an undetermined response in seven. Breast cancer patients were treated in 395 sites with CR in 222, PR in 74, SD in one, NR in 92, and undetermined response in six. The lung cancer patients in this series responded poorly, if at all. In addition to the above patient trials, we have investigated the interaction to laser hematoporphyrin derivative (HPD)- PRT with a chemotherapeutic agent, Cisplatin, against an experimental tumor (RIF-1) in an animal model. We have been unable to demonstrate an additive effect of laser HPD-PRT at total light doses of 25 j/cm2and 75j/cm2 with Cisplatin at a dose of 7 mg/kg. However, no additional toxicity was observed on combination therapy, suggesting that sequential application of laser HPD-PRT and Cisplatin may be safely employed in clinical situation. Another area of investigation has been the evaluation of the light-scattering characteristics of a lipid emulsion designed for laser HPD-PRT of bladder tumors. We have demonstrated that it is feasible to gain uniform illumination of the bladder surface with the use of this light-dispersing medium. We now believe that it is appropriate to begin clinical trials in which laser HPD-PRT is utilized as the initial form of therapy. Sites that appear most appropriate for this therapy are early cancers of the head and neck and early cancer of the bladder.