Elderly patients undergoing robot-assisted radical cystectomy (RARC) for muscle-invasive bladder cancer face high perioperative risk. Conventional risk stratification tools such as age, ASA score, and Charlson Comorbidity Index (CCI) often fail to predict postoperative complications accurately. The modified G8 (mG8) screening tool is a simplified frailty assessment developed for oncology patients but remains underexplored in surgical settings. This pilot study investigates the role of mG8 in predicting short-term morbidity and mortality following RARC.

We retrospectively analyzed 155 patients who underwent RARC with ileal conduit or orthotopic neobladder diversion from 2011 to 2020 at a single institution. Preoperative mG8 scores (excluding self-assessment item) were recorded, with a score ≥6 indicating frailty. Primary outcomes included severe postoperative complications (Clavien-Dindo Grade ≥3) and 90-day mortality. Logistic regression assessed associations between mG8 score, age, CCI, and clinical outcomes.

The median age was 69 years, with 76.1% male. An impaired mG8 score was present in 31.6% of patients. Severe complications occurred in 43.2%, and 90-day mortality was 6.5%. In multivariable analysis, impaired mG8 score was independently associated with severe complications (OR 2.65, 95% CI 1.29–5.45, p=0.008) and 90-day mortality (OR 5.72, 95% CI 1.46–22.81, p=0.015). Age and CCI were not independent predictors of these outcomes.

The mG8 score is a practical and effective preoperative tool that outperforms traditional metrics in identifying frail patients at risk of complications and mortality following RARC. Prospective, multicentre validation is warranted to confirm its utility in surgical decision-making and risk stratification.