Predictive Factors for Gastrointestinal and Hepatic Adverse Events During 5-Aminolevulinic Acid–Guided Photodynamic Diagnosis in Bladder Cancer: Exploratory Analysis of the Phase III SPP2C102 Trial

Objective: To evaluate the incidence and clinical predictors of gastrointestinal and hepatic adverse events following oral administration of 5-aminolevulinic acid hydrochloride (5-ALA) before transurethral resection of bladder tumors (TURBT). Methods : Safety data were analyzed from 145 patients enrolled in the prospective, single-arm, multicenter phase III SPP2C102 trial who received 5-ALA 4–8 h before TURBT. The incidence and severity of nausea, vomiting, and liver dysfunction, defined by elevations in aspartate aminotransferase, alanine aminotransferase, and/or gamma-glutamyltransferase, were assessed according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Potential risk factors were evaluated using univariable and multivariable logistic regression; results are reported as adjusted odds ratios (aOR) with 95% confidence intervals (CIs). Results: Nausea/vomiting occurred in 28/145 patients (19.3%), all CTCAE grade 1–2. Female sex was independently associated (aOR 3.15, 95% CI 1.17–8.47), and diastolic blood pressure ≥ 80 mmHg showed a borderline association (aOR 2.37, 95% CI 0.99–5.78). Prophylactic antiemetics yielded a numerically lower rate (21.1% vs. 9.1%; p = 0.25). Liver-enzyme elevations similarly occurred in 28/145 patients (19.3%), all CTCAE grade 1–2. Systolic blood pressure ≥ 130 mmHg remained independently associated (aOR 4.73, 95% CI 1.62–13.78), whereas associations for hypertensive comorbidity and BMI ≥ 25 kg/m² in univariable analyses did not persist after adjustment. Conclusion: 5-ALA–related nausea, vomiting, and transient liver-enzyme elevations were common but generally mild. Simple bedside variables—particularly sex and blood pressure—may guide selective antiemetic prophylaxis and closer biochemical monitoring in routine practice.