Photodynamic diagnosis of breast tumours after oral application of aminolevulinic acid

Photodynamic diagnosis is of increasing interest for diagnosis in oncology. It is based on a more intense incorporation of a fluorescent dye in rumour s compared to normal tissue. As a feasibility study we investigated the eff ectiveness of oral application of 5-aminolevulinic acid for photodynamic di agnosis of human primary mammary tumours. The study included 16 patients wi th palpable breast tumours. Aminolevulinic acid was administered at a conce ntration of 40 mg kg(-1) bodyweight 150-420 min prior to tumourectomy. Intr aoperatively blue light (405 nm) was applied to the operation site. Section s of the excised tumour and some lymph nodes were prepared and analysed wit h a fluorescent microscope. All primary mammary tumour tissues showed signi ficantly higher fluorescence intensity than surrounding normal mammary tiss ue. Fluorescence of the mammary tumours could also be discriminated macrosc opically and intraoperatively. Fluorescence intensity in nonmetastatic lymp h node tissue was higher in 2 out of 3 patients than in primary tumour tiss ue. By photodynamic diagnosis using aminolevulinic acid we were able to rel iably distinguish primary mammary tumours from normal mammary tissue micros copically and macroscopically in all our patients. We suggest that photodyn amic diagnosis with aminolevulinic acid for breast tumours should be furthe r investigated and developed for intraoperative use and may well be a simpl e tool for better intraoperative diagnosis and recognition of tumour margin s. We hypothesize that lymph node metastasis of breast tumours will not be detectable by this method. (C) 2001 Cancer Research Campaign http://www.bjc ancer.com.