(UroToday.com) The 2024 American Urological Association (AUA) Annual Meeting held in San Antonio, TX between May 3rd and 6th, 2024 was host to a bladder and upper tract transitional cell carcinoma podium session. Dr. Takeshi Sano presented the results of a single-center, retrospective analysis evaluating the diagnostic performance of photodynamic diagnosis with oral 5-aminolevulinic acid (ALA) for bladder and upper tract urothelial carcinoma.
Photodynamic diagnosis (PDD) enhances the endoscopic detection of urothelial carcinoma in the urinary tract. While there is plenty of evidence to support its role in bladder tumors, there are concerns that this modality may be limited in the upper tract setting owing to the cylindrical anatomy/morphology of the upper tracts.
The objective of this study was to compare the performance of PDD enhanced with oral 5-ALA between the bladder and upper tract. The study cohort included 18 patients with upper tract disease from the PDD-URS cohort of 20 patients who were enrolled in this prospective clinical trial and 110 consecutive bladder cancer patients from the PDD-TURBT cohort.
The baseline patient characteristics are summarized below. The median patient age was 76–78 years. Pre-operative urine cytology was suspicious or malignant in 22% of patients in the PDD-URS cohort versus 62% of patients in the PDD-TURBT cohort. 61% of patients in the PDD-URS cohort had visible tumors versus 44% in the PDD-TURBT cohort. In the PDD-TURBT cohort, 62 (56.4%) and 30 patients (27.3%) had a history of TURBT and BCG treatment, respectively.
In patients in the PDD-URS cohort, PDD was associated with a sensitivity of 91%, specificity of 76%, and AUC of 0.84 for the diagnosis of upper tract disease. This significantly outperformed white light endoscopy in all these domains. Conversely in the PDD-TURBT cohort, PDD demonstrated a sensitivity of 71%, specificity of 75%, and AUC of 0.73 for diagnosing bladder tumors. The performance of white light endoscopy was comparable to PDD as demonstrated by comparable AUCs (0.69 and 9.73). Overall, it appears that the performance of PDD was superior in the upper tract (AUCs: 0.84 versus 0.73).
Amongst patients in the PDD-TURBT group, stratified by prior TURBT (naïve versus recurrent) and BCG treatment, it appears that PDD had the best performance characteristics in the PDD-TURBT naïve subgroup.
In the PDD-URS cohort, 63 biopsy samples were obtained of which 25 were obtained from endoscopically negative sites and 38 from endoscopically suspicious/positive sites. Of the 25 endoscopic negative biopsy samples, 22 (88%) were negative for malignancy. Conversely, only 18% of those from suspicious/positive sites were negative for disease. The corresponding figures from the PDD-TURBT sample were 79% and 34%, respectively.
What are the pathologic findings of PDD false-positive lesions? In the PDD-URS cohort, 4 out of 7 samples had features of potential precancerous lesions (one suspicious for malignancy and three dysplasia). In contrast, only eight of 101 samples in the PDD-TURBT cohort showed precancerous features (four suspicious for malignancy and four dysplasia). Thus, PDD false-positive samples in the PDD-URS cohort showed a significantly higher incidence of precancerous findings than those in the PDD-TURBT cohort. Imaged below are two pictures showing PDD false-positive samples in the PDD-URS cohort.
Most of the PDD false-positive samples in the PDD-TURBT cohort had features of reactive changes, such as inflammation and vascular proliferation. The image on the left shows a PDD-negative normal urothelium, and the image on the right shows a false-positive sample with infiltration of immune cells and proliferation of vasculature. The arrowheads indicate blood vessels under the urothelium.
Dr. Sano concluded that:
- PDD in the upper urinary tract exhibits a better overall diagnostic performance compared with that in the bladder.
- False positive PDD samples in the PDD-URS cohort show a significantly higher incidence of precancerous findings compared to those in the PDD-TURBT cohort.
Presented by: Takeshi Sano, MD, PhD, FRCS, Department of Urology and Andrology, Kansai Medical University, Osaka, Japan
Written by: Rashid Sayyid, MD, MSc - Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2024 American Urological Association (AUA) Annual Meeting, San Antonio, TX, May 3rd - 6th, 2024