EAU 2024: Photodynamic Diagnosis (PDD) Directed Biopsies vs White Light Bladder Mapping in Patients with Positive Cytology and Negative Preoperative Workup: An International Multicenter Retrospective Study

(UroToday.com) The 2024 European Association of Urology (EAU) annual congress held in Paris, France between April 5th and 8th was host to a non-muscle invasive bladder cancer (NMIBC) abstract session. Dr. Fulvia Colucci presented the results of an international multicenter retrospective study of photodynamic diagnosis (PDD) directed biopsies versus white light bladder mapping in patients with positive cytology and a negative preoperative workup.

Dr. Colucci noted that bladder carcinoma in situ (CIS) is a flat, non-vegetating, high-grade tumor and is associated with a high risk of disease progression to muscle invasive cancer (MIBC), especially if not diagnosed and treated in a timely fashion. Since it may not be visible with white light cystoscopy (WL), international guidelines recommend the use of bladder mapping in case of suspected CIS (positive urine cytology and negative preoperative workup). Photodynamic diagnosis (PDD) has been shown to improve the sensitivity for the detection of CIS compared to WL cystoscopy and can be used for this purpose, when available. However, a direct comparison between PDD-guided biopsies and WL bladder mapping is lacking. The aim of this study was to compare the diagnostic ability of PDD-guided biopsies with that of WL bladder mapping for detecting CIS using a large multicenter international cohort of patients.

The investigators conducted a retrospective analysis across 6 European referral centers of patients with a positive urinary cytology and negative flexible cystoscopy and/or negative CT scan between March 2018 and September 2023. Patients with visible lesions or areas suspicious for CIS at WL cystoscopy were excluded. Eligible patients were those who underwent either PDD-guided biopsies or WL bladder mapping, as per international guidelines. The primary study endpoint was the sensitivity for the detection of CIS. Recurrence-free and progression-free survivals were investigated as secondary endpoints.

Overall, 149 patients (54%) underwent PDD-guided biopsies, while 126 (46%) received WL bladder mapping. There were no differences in baseline characteristics between the two groups. Bladder CIS was detected in 21 patients (14%) among the PDD-guided biopsies group and in 11 patients (9%) among the WL bladder mapping group (p=0.2). On univariable logistic regression analysis, the intervention modality was not significantly associated with the odds of CIS diagnosis (OR: 1.72, 95% CI: 0.79–3.71). There were no significant differences in disease recurrence rates (p=0.08) or progression-free survival (p=0.6) between patients across the two modalities.

Dr. Colucci concluded that there were no statistically significant differences between the PDD-guided biopsies and the WL bladder mapping groups for the diagnosis of CIS. WL bladder mapping remains a valid alternative to PDD-guided biopsies in patients with suspected CIS, when PDD equipment is not available. The main limitations of this study are inherent to its retrospective nature and possible underlying selection biases.

Presented by: Fulvia Colucci, MD, AOU Città della Salute e della Scienza di Torino University of Turin School of Medicine, Dept. of Urology, Turin, Italy 

Written by: Rashid Sayyid, MD, MSc - Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2024 European Association of Urology (EAU) annual congress, Paris, France, April 5th - April 8th, 2024