Known as Foscan photodynamic therapy (PDT) 1, it is an "effective and well tolerated treatment" and can be administered without surgery, said Mr Colin Hopper of the National Medical Laser Centre, in London.
Addressing ECCO 11 -the European Cancer Conference in Lisbon, Mr Colin Hopper presented the results of a study examining the response to Foscan PDT of 114 patients with primary head and neck cancers.
After two years of follow up, the data showed that 85% of patients achieved a complete response (elimination of the tumour) with PDT alone, and a further 6% achieved a complete response with PDT followed by surgery or radiotherapy - an overall response rate of 91%.
The one-and two-year overall survival rates were 90% and 81% respectively. Eleven patients died during the first year, but their deaths were not associated with the treatment.
Mr Hopper said "These response rates are comparable to those published for surgery or radiotherapy, but photodynamic therapy has the advantage of not being associated with the major toxicity of radiotherapy nor the tissue loss associated with surgery. It produces excellent cosmetic results, preserving form and function and does not compromise future treatment options."
This is particularly important, as there is a significant risk in head and neck cancer that another cancer will develop at or near the original site, requiring further treatment.
In PDT the drug or "photosensitizer" is injected into the body and is retained by cancer cells. When non-thermal laser light of the appropriate wavelength is shone onto the tumour, the photosensitizer absorbs the light and produces a highly reactive form of oxygen (so called "singlet oxygen") which destroys the surrounding cells. Normal healing takes place within months of treatment. The most common adverse event is pain at the treatment site due to the destruction of the tumour, but this can be managed with standard analgesic treatment. As the photosensitizing agent remains in the body for up to four weeks, patients must avoid bright light, but they can tolerate normal indoor light.
The study was conducted in 15 centres in six countries and was a non-randomised phase II study 11 in patients with primary head and neck cancers.
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