Fluorescence staining of laryngeal neoplasms after topical application of 5-aminolevulinic acid: preliminary results.
OBJECTIVE
The prognosis of patients suffering from laryngeal carcinomas can be improved by early diagnosis. Exact demarcation of tumor margins could contribute to an optimum preservation of the larynx. Therefore, the aim of the present study was the evaluation of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PPIX) fluorescence as a new diagnostic procedure for the detection of laryngeal cancer.


METHODS
Sixteen patients with suspected malignancies of the larynx received 0.6 wt% 5-ALA-NaCl solution by means of a medical nebulizer. After a period of 1-2 hours, the patients underwent microlaryngoscopy under white light and fluorescence illumination (lambda(ex) = 375-440 nm). A quantitative analysis of the fluorescence contrast between neoplastic and surrounding tissue was performed using an optical multichannel analyzer.


RESULTS
Carcinoma, carcinoma in situ, and dysplasia showed red fluorescence that could be attributed to the 5-ALA-induced formation of PPIX. The surrounding normal tissue exhibited autofluorescence in the green spectral range, which was greatly reduced within the tumor. The results of macroscopic red fluorescence staining were correlated with the histologic diagnosis.


CONCLUSIONS
According to these preliminary results, the presented method seems to be a promising adjunct diagnostic procedure for the early identification of malignant neoplasms in the larynx. The aim of further investigations is the assessment of sensitivity and specificity and an evaluation of fluorescence-guided laser resections of laryngeal cancer. Lasers Med. Surg. 25:414-420, 1999.
Mehlmann
M
M
Laser-Research Laboratory at the Department of Urology, Ludwig Maximilian University, 81377 Munich, Germany.
Betz
C S
CS
Stepp
H
H
Arbogast
S
S
Baumgartner
R
R
Grevers
G
G
Leunig
A
A
D000287:Administration, Topical; D000622:Aminolevulinic Acid / Q000008:administration & dosage; D001706:Biopsy; D005069:Evaluation Studies as Topic; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology*; D007828:Laryngoscopy; D009330:Nebulizers and Vaporizers; D017319:Photosensitizing Agents / Q000008:administration & dosage; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid