[Diagnosis of cervical squamous intraepithelial lesions by fluorescence imaging: clinical feasibility study]

Fluorescence diagnosis is still undeveloped in gynaecology. In order to diagnose and localize squamous intraepithelial lesion (SIL) of the cervix, a new method improving the low specificity of colposcopy would be useful. The goal of this study was to assess the feasibility and safety of colposcopic fluorescence diagnosis of SIL after topically application of methyl aminolevulinate (MAL).

Patients with histologic proved cervical intraepithelial neoplasia (CIN) and planned for loop electrosurgical excision procedure (LEEP) under general anesthesia were included in a prospective study. Before general anesthesia, a thick layer of MAL (Metvix-160 mg/mL cream) was applied on the cervix for 35-150 min. Fluorescent colposcopic inspection of the cervix was performed using a rigid 10-mm laparoscope inserted in the vaginal cavity and connected to D-light AF system (Karl Storz Endoskope, Tuttlingen Germany). In order to confirm neoplasic status, fluorescent foci underwent directed punch biopsy(ies).

Fourteen patients were included in the study. Colposcopic fluorescence imaging revealed red fluorescent foci in 71.4% of cases (10/14) (neoplasic status of fluorescent foci was confirmed in 80%). Concerning MAL, the mean of application time was 73 min (35-150). Two cases presented a false-positive fluorescence and four cases of false-negative fluorescence. For all cases of false-negative fluorescence, application time of MAL was less than 60 min. We observed no systemic or local toxicity of MAL application in any group.

Using topical application of MAL to the cervix, we demonstrated that fluorescence diagnosis of SIL is feasible. This study justifies the further development of fluorescence imaging that combines classical white light colposcopy with the use of a photosensitizer.