A Novel Clinically Based Staging System for Gallbladder Cancer
Background: Current staging systems for gallbladder cancer (GBC) are primarily based on surgical pathology and therefore are not relevant for unresectable patients and those undergoing neoadjuvant chemotherapy. Methods: Patients with a confirmed diagnosis of GBC managed at a tertiary referral center (2000–2016) were included. Independent predictors of overall survival (OS) were identified using multivariable analysis (MVA). A combination of these variables was then assessed to identify a set of factors that provided maximal accuracy in predicting OS, and a nomogram and a new staging system were created based on these factors. Harrell’s C-statistic was calculated to evaluate the predictive accuracy of the nomogram and staging system. Results: A total of 528 patients were included in the final analysis. On MVA, factors predictive of poor OS were older age, ECOG performance status, hemoglobin level <9 g/dL, presence of metastases, and alkaline phosphatase (ALP) level >200 U/L. A nomogram and a 4-tier staging system predictive of OS were created using age at diagnosis, ECOG status, tumor size, presence or absence of metastasis, and ALP level. The C-statistic for this novel staging system was 0.71 compared with 0.69 for the TNM staging system (P=.08). In patients who did not undergo surgery, the C-statistics of the novel and TNM staging systems were 0.60 and 0.51, respectively (P<.001). Conclusions: We created a novel, clinically based staging system for GBC based on nonoperative information at the time of diagnosis that was superior to the TNM staging system in predicting OS in patients who did not undergo surgery, and that performed on par with TNM staging in surgical patients.
Submitted May 8, 2019; accepted for publication September 4, 2019.
Previous presentation: This work was presented as a poster at the ASCO 2019 Gastrointestinal Cancers Symposium; January 17–19, 2019; San Francisco, California.
Author contributions: Concept and design: Yadav, Tella, Mahipal. Acquisition, analysis, or interpretation of data: Yadav, Tella, Prasai, Mara, Mahipal. Drafting of manuscript: Yadav, Tella, Kommalapati. Critical revision of manuscript for important intellectual content: All authors. Approval of final manuscript: All authors. Yadav, Tella, and Mahipal had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Disclosures: The authors have disclosed that they have not received any financial consideration from any person or organization to support the preparation, analysis, results, or discussion of this article.
Disclaimer: The research was conducted ethically in accordance with the World Medical Association Declaration of Helsinki. The study protocol was approved by the Mayo Clinic Committee on Human Research.
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