A post-clearance nomogram for predicting 12-month clinical recurrence after 5-ALA photodynamic therapy in patients...

To develop and internally validate a post-clearance prediction model for estimating 12-month clinical recurrence after 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) in patients with multiple penile condyloma acuminatum (CA) who achieved clinical complete clearance, and to define its role in follow-up planning.

This single-center retrospective cohort study included adults with multiple penile CA who received standardized 5-ALA PDT between January 2018 and December 2024 and achieved clinical complete clearance. The database was locked on December 31, 2025, ensuring at least 12 months of post-clearance follow-up. The index time point was documented clinical complete clearance, and the endpoint was 12-month clinical recurrence. Candidate predictors included baseline clinical, virological, host-related, and treatment-course variables available by the post-clearance time point. LASSO regression was used for variable selection, followed by multivariable logistic regression. Model performance was evaluated using ROC-AUC, bootstrap internal validation, calibration measures, Brier score, the Hosmer-Lemeshow test, and decision curve analysis.

Among 500 patients, 118 developed clinical recurrence within 12 months (23.6%). Multiple HPV infection, high-risk HPV positivity, higher wart number, mucosal involvement, immunosuppression, and previous treatment history independently predicted higher recurrence risk. A greater number of PDT sessions completed before clinical clearance was associated with lower observed recurrence risk within this post-clearance prediction framework. The fixed final model achieved an apparent AUC of 0.87 (95% CI, 0.83-0.90) and an optimism-corrected AUC of 0.85 after bootstrap internal validation. Calibration was favorable, with a non-significant Hosmer-Lemeshow test (P = 0.41), and decision curve analysis suggested exploratory net benefit across threshold probabilities of 10%-60%.

This internally validated post-clearance nomogram estimates 12-month clinical recurrence risk after 5-ALA PDT in patients with multiple penile CA. Because it incorporates treatment-course information and has not been externally validated, the model should be regarded as a preliminary tool for post-clearance follow-up planning, not as a pretreatment decision rule or justification for prescribing additional PDT sessions.