A new NCI-supported clinical trial has revealed that extended lymph node removal during surgery for localized muscle-invasive bladder cancer does not improve survival rates compared to standard lymph node removal. The study, published in the New England Journal of Medicine, challenges the conventional wisdom of more extensive surgery and suggests a more selective approach may be beneficial.
The trial, conducted by the SWOG Cancer Research Network, involved approximately 600 patients with localized muscle-invasive bladder cancer undergoing surgery to remove the bladder. Participants were randomly assigned to either standard or extended lymph node removal. After a median follow-up of 6.1 years, researchers found no statistically significant differences in overall survival or disease-free survival between the two groups.
No Survival Advantage, Increased Complications
The estimated 5-year disease-free survival was 60% in the standard surgery group and 56% in the extended group. The 5-year overall survival rates were 63% and 59%, respectively. These differences were not statistically significant. Furthermore, the extended surgery group experienced a higher incidence of serious side effects, such as anemia requiring blood transfusions and wound complications (54% versus 44%). There was also an increased risk of death within 90 days of surgery in the extended lymph node removal group.
According to Seth P. Lerner, M.D., of the Baylor College of Medicine and lead investigator of the study, these findings, combined with those of a previous German trial, indicate that standard lymph node surgery is sufficient for most patients when performed meticulously.
Challenging Surgical Norms
Despite limited evidence, extended lymph node removal has become standard practice at many medical centers for muscle-invasive bladder cancer. The results of this trial highlight the importance of rigorous scientific evaluation of surgical procedures before widespread adoption.
Ashish Kamat, M.D., director of bladder cancer research at the University of Texas MD Anderson Cancer Center, anticipates that these findings will encourage surgeons to adopt a more selective approach to extended lymph node dissection. He emphasized that "less is often more," and the study demonstrates that extended lymph node dissection does not improve survival for most patients while increasing the risk of complications.
Future Research Directions
Dr. Lerner and his team are now analyzing bladder tumor tissue samples from trial participants to identify molecular profiles associated with survival. This research may help to personalize surgical approaches in the future.
The trial's findings have been generally well-received by the surgical community, with some surgeons expressing relief at no longer needing to perform extended node dissections in the patient population represented in the trial. The results empower surgeons to avoid unnecessary harm, potentially leading to faster recovery and improved quality of life for patients.
