5582 Background: Administration of 5-aminolevulinic acid (5-ALA) results in tumor-selective accumulation of protoporphyrin IX, enabling visualization of malignant lesions as red fluorescence under blue light illumination. Although 5-ALA–based photodynamic diagnosis (ALA-PDD) is well established for non-muscle invasive bladder cancer, its role in gynecologic malignancies remains insufficiently characterized. We conducted an investigator-initiated clinical study to evaluate the efficacy and safety of ALA-PDD in ovarian, fallopian tube, and primary peritoneal cancers. Methods: From October 2024 to May 2025, patients scheduled for cytoreductive surgery or exploratory laparotomy were enrolled. After exclusion of one patient due to a change in treatment strategy, 22 patients received oral 5-ALA hydrochloride (20 mg/kg) 3–8 hours prior to surgery. Diagnostic performance for detecting peritoneal dissemination under blue light (BL) was compared with that under conventional white light (WL), assessing sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Statistical tests were performed using McNemar’s-test (sensitivity and specificity) or Chi-square test (PPV and NPV). Safety was evaluated based on the incidence and severity of adverse events. Results: Overall sensitivity was comparable between BL and WL (88.8% vs 80.9%), whereas BL demonstrated significantly higher specificity (67.3% vs 51.9%, p = 0.0229), indicating fewer false-positive findings. Notably, in patients undergoing interval debulking surgery (IDS; n = 9), BL significantly outperformed WL across all diagnostic metrics, including sensitivity, specificity, PPV, and NPV (all p < 0.05). These findings suggest that ALA-PDD enables more accurate intraoperative discrimination between malignant and non-malignant lesions following neoadjuvant chemotherapy. All patients experienced adverse events, predominantly Grade ≤2. One case of postoperative ileus was reported; however, no causal relationship with 5-ALA was identified, and no clinically relevant safety signals emerged. Conclusions: ALA-PDD appears to enhance intraoperative diagnostic accuracy compared with conventional white light inspection and demonstrates an acceptable safety profile in ovarian, fallopian tube, and primary peritoneal cancers. In IDS patients, ALA-PDD may serve as a clinically meaningful adjunct to achieve precise cytoreduction and support surgical decision-making in the neoadjuvant chemotherapy setting. Clinical trial information: jRCTs031240345.
Motohashi et al. (Wed,) studied this question.