Development and validation of a nomogram for predicting postoperative survival in gallbladder cancer

Gallbladder cancer (GBC) exhibits significant heterogeneity in postoperative prognosis, and the traditional tumor-nodes-metastasis (TNM) staging system has limitations in individualized survival prediction. This study aimed to develop and validate a nomogram integrating preoperative systemic status, ultrasonographic features, and postoperative pathological parameters for quantitatively predicting the overall survival (OS) of GBC patients after surgery, to aid clinical risk stratification and decision-making.

Clinicopathological data of 61 GBC patients who underwent surgical treatment at Peking Union Medical College Hospital (PUMCH) between August 2008 and December 2022 were retrospectively collected. Univariate and multivariate Cox proportional hazards regression models were employed to screen for independent prognostic factors. The model was optimized based on the Akaike Information Criterion (AIC), and a nomogram for predicting 1-year, 3-year, and 5-year OS was constructed. Internal validation was performed using the Bootstrap method (500 resamples). The model's discrimination and calibration were comprehensively assessed using the concordance index (C-index), time-dependent receiver operating characteristic (ROC) curves, and calibration curves. The optimal cutoff value for the risk score was determined using the maximal selected rank statistics (MaxStat) method.

During the median follow-up period, 54.1% of patients died. Multivariate Cox regression analysis identified four independent adverse prognostic factors: elevated American Society of Anesthesiologists (ASA) classification [grade III vs. grade I: hazard ratio (HR) =9.68, 95% confidence interval (CI): 2.46-38.01, P=0.001], preoperative low serum albumin (Alb) (per 1 g/L decrease: HR =1.10, P=0.03), lymph node metastasis (N1/N2 vs. N0: HR =4.72, 95% CI: 1.90-11.74, P<0.001), and hyperechoic tumor appearance on ultrasonography (hyperechoic vs. hypoechoic: HR =7.69, 95% CI: 1.35-43.70, P=0.02). The nomogram constructed based on these factors demonstrated excellent discrimination (C-index =0.733). The area under the curve (AUC) values for predicting 1-year, 3-year, and 5-year survival rates were 0.882, 0.845, and 0.840, respectively. Calibration curves showed high agreement between predicted probabilities and actual observations. The risk stratification system divided patients into low-risk and high-risk groups, with the high-risk group having a median survival of only 14.5 months (P<0.001).

The nomogram developed in this study innovatively integrates multidimensional indicators reflecting patients' physiological reserve (ASA classification), nutritional/immune status (Alb), and tumor biological behavior (ultrasonographic echogenicity, N stage). Notably, the discovery of "hyperechoic" appearance as an independent adverse prognostic imaging marker holds significant clinical implication. This model demonstrates high accuracy and strong practicality, effectively identifying high-risk postoperative populations and guiding individualized adjuvant therapy and follow-up strategies.