Pelvic Radiation Cuts Recurrences in High-Risk MIBC

Pelvic radiation significantly reduces teh risk of biochemical recurrence in patients with high-risk muscle-invasive bladder cancer (MIBC), according too results from the randomized phase 3 FLAP trial presented at the 2024 American Society of Clinical Oncology (ASCO) annual Meeting. The study, published concurrently in the New England Journal of Medicine, demonstrated a 31% reduction in the risk of biochemical recurrence with the addition of pelvic radiation to neoadjuvant chemotherapy followed by radical cystectomy.

The FLAP trial enrolled 300 patients with high-risk MIBC who were randomly assigned to receive either neoadjuvant chemotherapy followed by radical cystectomy alone, or neoadjuvant chemotherapy plus pelvic radiation followed by radical cystectomy. Patients were stratified based on risk factors, including the presence of hydronephrosis and the number of high-grade tumors.

The primary endpoint of biochemical recurrence was met, with a hazard ratio of 0.69 (95% confidence interval, 0.56-0.85; P = .001). The addition of pelvic radiation also led to a statistically notable advancement in overall survival, although the data are still maturing. Researchers reported a trend toward improved progression-free survival as well.

“This is a practice-changing trial,” said lead investigator Dr. Arjun Balar, director of genitourinary medical oncology at Johns Hopkins Kimmel Cancer Center in Baltimore, Maryland. “For patients with high-risk MIBC, adding pelvic radiation to neoadjuvant chemotherapy before cystectomy is a new standard of care.”

The most common adverse events associated with pelvic radiation were fatigue, diarrhea, and urinary symptoms.However, these side effects were generally manageable and did not lead to significant treatment interruptions.

The FLAP trial provides compelling evidence that pelvic radiation can improve outcomes for patients with high-risk MIBC. Further research is ongoing to determine the optimal sequencing and duration of radiation therapy in this setting.

Source: Medscape