Retrospective Cohort Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Aug 15, 2023; 15(8): 1436-1450
Published online Aug 15, 2023. doi: 10.4251/wjgo.v15.i8.1436
Comparison of clinicopathological characteristics and survival outcomes between gallbladder mucinous adenocarcinoma and gallbladder adenocarcinoma: A propensity score-matched study
Wen-Wei Yang, Yu-Ting Fang, Ya-Ru Niu, Yong-Kun Sun
Wen-Wei Yang, Yu-Ting Fang, Ya-Ru Niu, Yong-Kun Sun, Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
Yong-Kun Sun, Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Hebei Cancer Hospital, Langfang 065001, Hebei Province, China
Author contributions: Yang WW contributed to the study design, data collection and analysis, and manuscript composition; Fang YT and Niu YR helped to perform and check the statistical analysis; Sun YK contributed to proofreading and final approval of the article; All authors read and approved the final version.
Supported by The National Key Research and Development Program of China, No. 2021YFF1201300.
Institutional review board statement: As the SEER database is publicly available and de-identified, therefore, the ethical approval was exempted by the ethics committee of our hospital.
Informed consent statement: The SEER database is a public-use database. After submitting a request to the SEER database project and obtaining permission, data freely downloaded from the SEER database did not require patients’ informed consent or institutional approval.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at email address. Participants gave informed consent for data sharing.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Yong-Kun Sun, MD, Professor, Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 17 Panjiayuan Nanli, Chaoyang District, Beijing 100021, China. hsunyk@cicams.ac.cn
Received: March 25, 2023
Peer-review started: March 25, 2023
First decision: May 22, 2023
Revised: June 3, 2023
Accepted: June 19, 2023
Article in press: June 19, 2023
Published online: August 15, 2023
Processing time: 138 Days and 4.6 Hours
ARTICLE HIGHLIGHTS
Research background

Gallbladder carcinoma (GBC) is the most common biliary tract cancer worldwide and the sixth most common gastrointestinal tumor. GBC is widely regarded as a highly aggressive malignancy with a poor overall 5-year survival rate of less than 5% and median overall survival (OS) of only six months. The biological features, clinical manifestations, and prognoses are obviously different in various histological subtypes of GBC. Gallbladder mucinous adenocarcinoma (MAC) (GBMAC) is an uncommon subtype of gallbladder adenocarcinoma (GBAC) and has unique clinicopathological characteristics and prognosis.

Research motivation

Due to the rarity of GBMAC, there are few large randomized clinical studies of GBMAC, and characterization of clinicopathological features, prognosis, and clinical risk factors have been limited to individual case reports or small retrospective series. With limited understanding, clinical practices in typical GBAC are also applied to GBMAC. However, GBMAC has distinct histologic, clinical, and molecular features, thus making a differential approach necessary. The clinical prognosis of GBMAC compared to typical GBAC remains unknown.

Research objectives

We performed a retrospective analysis to investigate clinicopathologic characteristics, prognostic factors, and treatment outcomes for GBMAC by comparing GBMAC patients and typical GBAC patients using data from the Surveillance, Epidemiology, and End Results (SEER) database.

Research methods

This retrospective study was conducted using data from the SEER database. Cases of GBMAC and typical GBAC diagnosed between January 2010 and December 2017 were included in this study. Finally, 187 GBMAC patients and 4524 typical GBAC were included in the study. To analyze the prognostic factors of GBMAC, the clinicopathological features and OS of these GBMAC patients were compared with a large cohort of typical GBAC patients. The Pearson chi-square test or Fisher exact test was used to examine the differences between these two cohorts. In addition, a propensity score matching (PSM) analysis was performed to balance the differences and biases between the GBMAC and typical GBAC groups. The PSM model was based on race, marital status, radiotherapy status, and American Joint Committee on Cancer (AJCC) stage. The baseline characteristics of the GBMAC and typical GBAC were also determined in the matched data. Cox proportional hazards models were used to analyze associations of different variables with OS and cancer-specific survival (CSS). Only variables significantly associated with survival in the univariate Cox analysis were included in the multivariate Cox analysis. Hazard ratios and 95% confidence intervals were calculated, and the univariate and multivariate Cox analyses were applied to the whole and matched data set. Moreover, the Kaplan-Meier method was used to establish the survival curves, and the log-rank test was used to assess any significant differences in OS and CSS stratified by histology before and after PSM. The univariable survival analysis applied the Kaplan-Meier method and log-rank test to identify statistically significant covariates associated with CSS. Statistical analyses were performed using the R software (version 4.1.2).

Research results

In our study, compared with typical GBAC, GBMAC was significantly associated with unmarried status, advanced AJCC stage, higher T stage, higher N1 stage rate, and lower N0 and N2 stage rates. After PSM analysis, there were no significant differences in the characteristics between these two groups. After univariate and multivariate analyses, only surgery, chemotherapy, and AJCC stage IV were independent risk factors for OS of GBMAC patients. Similar results were observed in multivariate analysis of CSS. Surgery, chemotherapy, and AJCC stage III and IV were independent prognostic indicators for CSS of GBMAC patients. As for OS and CSS, there was no significant difference between GBMAC and typical GBAC patients in the whole cohort. In the PSM cohort, patients with GBMAC also had similar OS and CSS to matched typical GBAC patients.

Research conclusions

Compared with typical GBAC, GBMAC showed different demographical and clinicopathological features with aggressive biological behaviors. The OS and CSS were not worse for patients with GBMAC than those with typical GBAC. Furthermore, we explored the correlation between various variables and the survival time of GBMAC patients. Finally, three prognostic predictors for GBMAC patients were identified, including surgery status, chemotherapy status, and AJCC stage.

Research perspectives

A further prospective study with large sample size and more comprehensive prognostic information is desired to verify our findings.