En Bloc, Standard Resection for NMIBC Compared

BY JOHN SCHIESZER

EN BLOC resection has the potential to improve outcomes in patients with non-muscle invasive bladder cancer (NMIBC) compared with standard resection, according to investigators.

In the multicenter, randomized phase 3 EB-StaR trial, which compared the surgical approaches in patients with tumors measuring 3 cm or less, researchers found that patients having an en bloc resection had a significantly lower 1-year recurrence rate (the trial’s primary outcome) compared with those undergoing standard resection (28.5% vs 38.1%).

“Bladder tumors are resected in a piecemeal manner,” said Jeremy Teoh, MD, an assistant dean and Associate Professor of Urology at The Chinese University of Hong Kong, who presented the study findings at the American Urological Association’s 2023 Annual Scientific Meeting. “It is difficult to ensure a complete and uniform tumor resection down to the detrusor muscle layer. Therefore, residual tumor can be present even after standard resection.” bloc resection, complete resection can be ascertained not only by the surgeon’s judgment, but also based on the histological assessment of the resection margins of the en bloc resected specimen.”

During standard resection, tumor cells float inside the bladder, Dr Teoh explained. These tumor cells can reimplant to the bladder mucosa and lead to early disease recurrence.

The 1-year progression rate was 0% in the en bloc group and 2.6% in the standard resection arm, a nonsignificant difference. The en bloc group had a significantly longer operative time compared with the standard resection group (33.4 vs 24.7 minutes).

All other outcomes were similar between the treatment arms, according to investigators. These included the detrusor muscle sampling rates, occurrence of obturator reflex, use of postoperative mitomycin C instillation, 30-day complication rate, hospital stay, and residual disease and upstaging of disease.

If en bloc was widely adopted, it could help minimize tumor fragmentation and the risk of tumor re-implantation, he said.

“I strongly believe oncological principles exist for good reasons. En bloc resection aims to uphold all oncological principles, and I am not surprised it did lead to a better oncological control,” he said.

“As urologists, we should try our best to perform high-quality surgery in order to deliver the best possible outcomes.”

For EB-StaR trial, the investigators randomly assigned 276 patients with histologically confirmed NMIBC to receive an en bloc procedure (143 patients, mean age 69.6 years, 75.5% male) or undergo standard resection (133 patients, mean age 69.1 years, 82.7% male).

“En bloc resection is a potentially superior technique in treating bladder cancer,” Dr Teoh said. “It is important to have a large-scale multicenter randomized trial to investigate whether en bloc resection can lead to a better oncological control in patients with nonmuscle-invasive bladder cancer. With en

Chad R. Ritch MD, MBA, associate professor of urologic oncology within the Desai Sethi Urology Institute at the University of Miami’s Miller School of Medicine in Florida, said the current study is notable because it could lead to increased use of en bloc in this patient