New Study Links Frailty and Microbial Imbalance to GI Risks in Bladder Cancer Surgery

Gastrointestinal (GI) complications following radical cystectomy for bladder cancer continue to pose significant challenges for patient recovery. A study published in the journal Scientific Reports on July 1, 2025, reveals that both frailty and microbial imbalance are critical factors contributing to these complications. The research team, led by Associate Professor Kenji Zennami of Nagoya University School of Medicine and Fujita Health University School of Medicine in Japan, discovered a substantial link between the gut microbiota and postoperative outcomes in patients undergoing robot-assisted radical cystectomy with intracorporeal urinary diversion (iRARC).

The study involved analyzing fecal samples from the distal ileum and ascitic fluid of 146 patients who underwent iRARC without bowel preparation and received short-term antibiotic prophylaxis. Despite the antibiotics, the researchers found that persistent intra-abdominal bacteria and fungi were strongly associated with GI complications, such as postoperative ileus (POI) and intra-abdominal infections (IAI).

Dr. Zennami stated, “Although the distal ileal microbiota is usually sparse under short-term antibiotic prophylaxis, our findings show that the presence of residual intra-abdominal bacteria or fungi is strongly linked to GI complications.” The research highlights a concerning statistic: patients with positive bacterial or fungal growth in their ascitic fluid exhibited more than a six-fold increased risk of developing complications, with 72.5% of these patients facing POI or infection, compared to just 11.3% among those with negative cultures.

Impact of Frailty on Microbial Imbalance

Frailty emerged as a significant contributor to these complications. Using the Geriatric-8 questionnaire, the researchers identified frail patients as being more likely to harbor residual microbes and experience adverse outcomes. Only 12% of non-frail patients encountered GI complications, while this figure soared to 63% among frail individuals. Notably, frail patients displayed a unique microbial profile, with a higher prevalence of Enterococcus and Enterobacter, including strains resistant to carbapenems, which were absent in non-frail patients.

Dr. Zennami emphasized the limitations of current surgical techniques and perioperative protocols in fully preventing GI complications. “Frailty and gut microbiota play an equally important role, and addressing these factors may be essential for improving patient outcomes,” he added.

The findings carry significant implications for clinical practice. Current guidelines for perioperative antibiotic prophylaxis in urology are inconsistent. The study suggests that prophylactic regimens should be customized to target organisms likely to persist in frail patients. Additionally, incorporating frailty assessments and prehabilitation programs—such as exercise and nutritional support—into surgical planning may enhance recovery.

Future Directions for Patient Care

Microbiota-based interventions, including the use of probiotics and synbiotics, could further mitigate the risk of POI and infections by promoting a healthier gut environment prior to surgery. Although the study was conducted at a single center and utilized conventional culture methods, it offers some of the first direct evidence that frailty-associated gut dysbiosis is linked to negative surgical outcomes in bladder cancer patients.

The researchers advocate for larger, multicenter studies to validate these findings and to explore targeted interventions. “In the future, we may see microbiota-based management become a standard component of perioperative care,” concluded Dr. Zennami. “By integrating frailty assessment with strategies that support a healthier gut environment, we have the potential to improve recovery, reduce complications, and tailor treatment for vulnerable patients.”