Trajectories of squamous cell carcinoma antigen and outcomes of patients with advanced penile cancer after chemotherapy based on paclitaxel, ifosfamid, and cisplatin regimen

Abstract Introduction Penile cancer (PC) is a lethal malignancy with no effective prognostic biomarker. We aim to investigate associations between trajectories of squamous cell carcinoma antigen (SCC‐A) and patient outcomes after chemotherapy based on paclitaxel, ifosfamid, and cisplatin (TIP) regimen. Methods Consecutive AJCC staging III/IV PC patients who received TIP chemotherapy and repeated SCC‐A measurements in 2014–2022 were analyzed. Latent class growth mixed (LCGM) models were employed to characterize patients' serum SCC‐A trajectories. Patient survival, and clinical and pathological tumor responses were compared. Inverse probability treatment weighting was used to adjust confounding factors. Results Eighty patients were included. LCGM models identified two distinct trajectories of SCC‐A: low‐stable (40%; n = 32) and high‐decline (60%; n = 48). Overall survival (HR [95% CI]: 3.60 [1.23–10.53], p = 0.019), progression‐free survival (HR [95% CI]: 11.33 [3.19–40.3], p