Primary signet-ring cell carcinoma of the bile duct: clinical characteristics, survival comparison with cholangiocarcinoma, and SEER-based prognostic nomograms.

ABSTRACT:

Background

Signet-ring cell carcinoma (SRCC) of the bile duct is a rare malignancy with poorly characterized clinical features and prognosis. Given its rarity and the critical need to differentiate its behavior from common cholangiocarcinoma (CCA), this population-based study aimed to characterize SRCC and compare survival outcomes with CCA, while developing prognostic nomograms for individualized prediction.

Methods

We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database [2000-2021], identifying 98 SRCC and 18,979 CCA cases. Propensity score matching (PSM) analysis (1:5 ratio) was conducted to balance baseline characteristics between groups (98 SRCC vs. 490 CCA). Independent prognostic factors for overall survival (OS) and cancer-specific survival (CSS) were identified using multivariable Cox regression. These factors were incorporated into nomograms for OS and CSS prediction. Model performance was evaluated using the concordance index (C-index), calibration curves, receiver operating characteristic (ROC) curve analysis, and decision curve analysis (DCA).

Results

SRCC predominantly involved the extrahepatic bile duct (86.7%) and exhibited poor survival [median OS (mOS) 7.0 months, 95% confidence interval (CI): 4.0-10.0; median CSS (mCSS) 8.0 months, 95% CI: 5.0-12.0]. After PSM, no significant survival difference was observed between SRCC and CCA (P>0.05). Older age and distant metastasis were independent factors associated with poor survival, whereas surgery and chemotherapy were independently associated with better survival. The nomograms demonstrated moderate predictive accuracy (C-index: OS 0.78, 95% CI: 0.71-0.84; CSS 0.78, 95% CI: 0.70-0.85). Calibration curves showed excellent agreement between predicted and observed survival, ROC analysis confirmed discriminative ability, and DCA indicated strong clinical utility.

Conclusions

SRCC of the bile duct is a rare, aggressive malignancy with a prognosis similar to CCA. The developed nomograms, integrating readily available clinical factors, provide clinically applicable tools for individualized prognosis prediction.

SUBMITTER: Wen Y 

PROVIDER: S-EPMC12554459 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature