(UroToday.com) On the second day of the American Society for Clinical Oncology (ASCO) Genitourinary Cancer Symposium 2022 focused on urothelial carcinoma, in Poster Session B, Dr. Kawai presented an analysis assessing the role of photodynamic diagnosis-assisted TURBT (PDD-TURBT) to reduce the residual tumor in patients with high-risk non-muscle-invasive bladder cancer (NMIBC). High-risk NMIBC has a high rate of residual tumor following TURBT (40-60%). Thus, many guideline bodies recommend a second re-TUR. However, photodynamic diagnosis-assisted TURBT (PDD-TURBT) using 5-aminolevulinic acid (5-ALA) has been reported to reduce residual tumors and intravesical recurrence.
In this investigator-initiated multicenter prospective observational study (BRIGHT study; UMIN000035712), the authors enrolled patients who underwent PDD-TURBT using 5-ALA and second TUR for high-risk NMIBC (high-grade UC or pT1 or concurrent CIS) and compared them to historical controls. The primary endpoint was tumor residual rate and the secondary endpoint was recurrence-free survival. The PDD-TURBT group was matched to historical controls using a propensity score with a caliper width of 0.2. Assuming a between-group difference of 20%, the planned number of cases was statistically set to 200 PDD-TURBT cases and 300 historical data cases, and the registration period was 2 years from January 2019 to December 2020 with follow-up continuing for 2 years after the second TUR.
The authors ended up including 188 patients in the PDD-TURBT group and 313 patients in the historical group of whom 177 patients and 306 patients were included in the final analysis, respectively. After PSM adjustment, 167 patients in both groups were compared, and no significant differences were observed in age, gender, history of bladder cancer, tumor diameter, number of tumors, history of upper tract urothelial cancer, and period from initial TURBT to second TUR. The tumor residual rate was 25.8% in the PDD-TURBT group compared with 47.3% in the historical group, showing a significant decrease (odds ratio 0.39 [95% CI: 0.24–0.63]; p = 0.000064).
Further, the authors identified that current or past smoking history, multiple tumors, and non-pTa (pT1 or pTis) tumors were associated with higher rates of residual tumor among patients treated with PDD-TURBT. Focusing on these three factors, patients with 0–1 of these three factors have a significantly lower tumor residual rate compared with patients with 2–3 factors (8.33% vs. 33.3%; odds ratio 5.46 [95% CI: 1.81–22.3]; p = 0.00052).
Thus, the authors concluded that the use of PDD-TURBT for high-risk NMIBC significantly reduced the tumor residual rate at the second TUR compared to the conventional TURBT. They therefore suggested that PDD-TURBT using 5-ALA may enable the omission of a second TUR in some patients with high-risk NMIBC.
Written By: Christopher J.D. Wallis, MD, Ph.D., Assistant Professor in the Division of Urology at the University of Toronto, @WallisCJD on Twitter during the 2022 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, Thursday Feb 17 – Saturday Feb 19, 2022