Background: To evaluate the clinical performance of photodynamic diagnostic (PDD) after oral administration of 5-aminolevulinic acid (5-ALA) for assessment of tumor type and surgical margins in laparoscopic nephron-sparing surgery.
Materials and methods: This is a prospective, non-randomized single-center study. A total of 77 patients with a renal mass < 4 cm diameter underwent laparoscopic partial nephrectomy (LPN). For photosensitization, 1.5 g 5-ALA was administered orally 4 h prior to surgery. During the operation, the resection site and the outer tumor border were inspected under excitation light for characteristic red fluorescence. The results of PDD were matched up to the histological findings.
Results: Mean operative time was 94.1 min with a mean warm-ischemia time of 23 min. Fifty-eight of 61 (95.1%) renal cell carcinomas showed a positive response when exposed to excitation light. In 16 cases (21%), final pathology revealed a nonmalignant lesion. However, characteristic fluorescence was also detected in 1 angiomyolipoma of 16 nonmalignant lesions. False-negative rate was 3/61 (4.9%) and false-positive rate was 1/77 (1.3%), with these data corresponding to a sensitivity of 95% and a specificity of 94%. Further, PDD with 5-ALA was able to predict the type of the lesion with an accuracy of 94% and with a positive predictive value of 98%. Furthermore, PDD with 5-ALA also identified both cases with positive resection margins, which were confirmed on histological examinations. No side effects of systemic 5-ALA administration were observed.
Conclusions: PDD after systemic administration of 5-ALA is a reliable tool to assess the type and the resection status of a suspected renal tumor during laparoscopic nephron-sparing surgery.