Analysis of gallbladder polypoid lesion size as an indication of the risk of gallbladder cancer

Interpretation, Reporting, Imaging-Based Workups, and Surveillance of Incidentally Detected Gallbladder Polyps and Gallbladder Wall Thickening: 2025 Recommendations From the Korean Society of Abdominal Radiology

Incidentally detected gallbladder polyps (GBPs) and gallbladder wall thickening (GBWT) are frequently encountered in clinical practice. However, characterizing GBPs and GBWT in asymptomatic patients can be challenging and may result in overtreatment, including unnecessary follow-ups or surgeries. The Korean Society of Abdominal Radiology (KSAR) Clinical Practice Guideline Committee has developed expert recommendations that focus on standardized imaging interpretation and follow-up strategies for both GBPs and GBWT, with support from the Korean Society of Radiology and KSAR. These guidelines, which address 24 key questions, aim to standardize the approach for the interpretation of imaging findings, reporting, imaging-based workups, and surveillance of incidentally detected GBPs and GBWT. This recommendation promotes evidence-based practice, facilitates communication between radiologists and referring physicians, and reduces unnecessary interventions.

Risk prediction and analysis of gallbladder polyps with deep neural network

The aim of this study is to analyze the risk factors associated with the development of adenomatous and malignant polyps in the gallbladder. Adenomatous polyps of the gallbladder are considered precancerous and have a high likelihood of progressing into malignancy. Preoperatively, distinguishing between benign gallbladder polyps, adenomatous polyps, and malignant polyps is challenging. Therefore, the objective is to develop a neural network model that utilizes these risk factors to accurately predict the nature of polyps. This predictive model can be employed to differentiate the nature of polyps before surgery, enhancing diagnostic accuracy. A retrospective study was done on patients who had cholecystectomy surgeries at the Department of Hepatobiliary Surgery of the Second People's Hospital of Shenzhen between January 2017 and December 2022. The patients' clinical characteristics, lab results, and ultrasonographic indices were examined. Using risk variables for the growth of adenomatous and malignant polyps in the gallbladder, a neural network model for predicting the kind of polyps will be created. A normalized confusion matrix, PR, and ROC curve were used to evaluate the performance of the model. In this comprehensive study, we meticulously analyzed a total of 287 cases of benign gallbladder polyps, 15 cases of adenomatous polyps, and 27 cases of malignant polyps. The data analysis revealed several significant findings. Specifically, hepatitis B core antibody (95% CI -0.237 to 0.061, p < 0.001), number of polyps (95% CI -0.214 to -0.052, p = 0.001), polyp size (95% CI 0.038 to 0.051, p < 0.001), wall thickness (95% CI 0.042 to 0.081, p < 0.001), and gallbladder size (95% CI 0.185 to 0.367, p < 0.001) emerged as independent predictors for gallbladder adenomatous polyps and malignant polyps. Based on these significant findings, we developed a predictive classification model for gallbladder polyps, represented as follows, Predictive classification model for GBPs = -0.149 * core antibody - 0.033 * number of polyps + 0.045 * polyp size + 0.061 * wall thickness + 0.276 * gallbladder size - 4.313. To assess the predictive efficiency of the model, we employed precision-recall (PR) and receiver operating characteristic (ROC) curves. The area under the curve (AUC) for the prediction model was 0.945 and 0.930, respectively, indicating excellent predictive capability. We determined that a polyp size of 10 mm served as the optimal cutoff value for diagnosing gallbladder adenoma, with a sensitivity of 81.5% and specificity of 60.0%. For the diagnosis of gallbladder cancer, the sensitivity and specificity were 81.5% and 92.5%, respectively. These findings highlight the potential of our predictive model and provide valuable insights into accurate diagnosis and risk assessment for gallbladder polyps. We identified several risk factors associated with the development of adenomatous and malignant polyps in the gallbladder, including hepatitis B core antibodies, polyp number, polyp size, wall thickness, and gallbladder size. To address the need for accurate prediction, we introduced a novel neural network learning algorithm. This algorithm utilizes the aforementioned risk factors to predict the nature of gallbladder polyps. By accurately identifying the nature of these polyps, our model can assist patients in making informed decisions regarding their treatment and management strategies. This innovative approach aims to improve patient outcomes and enhance the overall effectiveness of care.

Risk of developing gallbladder cancer in patients with gallbladder polyps detected on transabdominal ultrasound: a systematic review and meta-analysis

OBJECTIVE

To estimate the risk of malignancy in gallbladder polyps of incremental sizes detected during transabdominal ultrasound (TAUS).

METHODS

We searched databases including MEDLINE, Embase, and Cochrane Library for eligible studies recording the polyp size from which gallbladder malignancy developed, confirmed following cholecystectomy, or by subsequent follow-up. Primary outcome was the risk of gallbladder cancer in patients with polyps. Secondary outcome was the effect of polyp size as a prognostic factor for cancer. Risk of bias was assessed using the Quality in Prognostic Factor Studies (QUIPS) tool. Bayesian meta-analysis estimated the median cancer risk according to polyp size. This study is registered with PROSPERO (CRD42020223629).

RESULTS

82 studies published since 1990 reported primary data for 67,837 patients. 67,774 gallbladder polyps and 889 cancers were reported. The cumulative median cancer risk of a polyp measuring 10 mm or less was 0.60% (99% credible range 0.30-1.16%). Substantial heterogeneity existed between studies (I2 = 99.95%, 95% credible interval 99.86-99.98%). Risk of bias was generally high and overall confidence in evidence was low. 13 studies (15.6%) were graded with very low certainty, 56 studies (68.3%) with low certainty, and 13 studies (15.6%) with moderate certainty. In studies considered moderate quality, TAUS monitoring detected 4.6 cancers per 10,000 patients with polyps less than 10 mm.

CONCLUSION

Malignant risk in gallbladder polyps is low, particularly in polyps less than 10 mm, however the data are heterogenous and generally low quality. International guidelines, which have not previously modelled size data, should be informed by these findings.

ADVANCES IN KNOWLEDGE

This large systematic review and meta-analysis has shown that the mean cumulative risk of small gallbladder polyps is low, but heterogeneity and missing data in larger polyp sizes (>10 mm) means the risk is uncertain and may be higher than estimated.Studies considered to have better methodological quality suggest that previous estimates of risk are likely to be inflated.

Follow-up of gallbladder polyps in a high-risk population of gallbladder cancer: a cohort study and multivariate survival competing risk analysis

BACKGROUND

The risk of neoplasia in gallbladder polyps seems to be low, but the evidence from populations at high-risk of gallbladder cancer is limited. We aimed to estimate the risk and to identify the factors associated with neoplastic polyps in a high-risk Hispanic population.

METHODS

A retrospective cohort was recruited between January 2010 and December 2019 at a Chilean university center. Multivariate survival analyses were conducted. Fine-Gray models were fitted to account for competing risks. Covariate adjustment was conducted using propensity scores. The main outcome was the development of gallbladder adenomas or adenocarcinoma.

RESULTS

Overall, 748 patients were included, 59.6% underwent cholecystectomy. The median follow-up of patients not subjected to cholecystectomy was 54.7 months (12-128.6 months). Seventeen patients (2.27%) developed the outcome. After adjustment by age, sex, intralesional blood flow, lithiasis and gallbladder wall thickening, only polyp size (≥10 mm, adjusted-HR: 15.01, 95%CI: 5.4-48.2) and number of polyps (≥3 polyps, adjusted-HR: 0.11, 95%CI: 0.01-0.55) were associated with neoplasia.

CONCLUSION

In a Hispanic population at high-risk for gallbladder cancer, gallbladder polyps seem to have a low risk of neoplasia. Polyp size was the main risk factor, while having multiple polyps was associated with an underlying benign condition.

Causes of misdiagnosis and missed diagnosis and therapeutic and preventive strategies for unexpected gallbladder carcinoma

Laparoscopic cholecystectomy (LC) has been widely used in the treatment of gallbladder diseases. Since the indications for operation are constantly expanding, the intraoperative or postoperative incidence of unexpected gallbladder carcinoma (UGC) is gradually increasing. The incidence of UGC in LC and open cholecystectomy is 2.09% and 0.91%, respectively. Because gallbladder carcinoma is often accompanied by gallstones or inflammation and lacks specific clinical manifestations, imaging features, and specific serum tumor markers, the preoperative diagnostic rate of gallbladder carcinoma is only 30%, and 30% of cases of gallbladder carcinoma are diagnosed intraoperatively or postoperatively. Pathological T stage, lymph node metastasis, and gallbladder rupture are independent risk factors for the prognosis of patients with UGC. Preoperative imaging combined with serological tumor markers, intraoperative careful exploration, and rapid pathological examination are important measures to reduce the misdiagnosis and missed diagnosis of UGC. For patients with benign gallbladder diseases with a high potential of canceration, performing cholecystectomy in time and strictly grasping the indications for preserving gallbladder for benign gallbladder diseases are important preventive measures to reduce the incidence of UGC.

Gallbladder polyps: Correlation of size and clinicopathologic characteristics based on updated definitions

BACKGROUND

Different perspectives exist regarding the clinicopathologic characteristics, biology and management of gallbladder polyps. Size is often used as the surrogate evidence of polyp behavior and size of ≥1cm is widely used as cholecystectomy indication. Most studies on this issue are based on the pathologic correlation of polyps clinically selected for resection, whereas, the data regarding the nature of polypoid lesions from pathology perspective -regardless of the cholecystectomy indication- is highly limited.

METHODS

In this study, 4231 gallbladders -606 of which had gallbladder carcinoma- were reviewed carefully pathologically by the authors for polyps (defined as ≥2 mm). Separately, the cases that were diagnosed as "gallbladder polyps" in the surgical pathology databases were retrieved.

RESULTS

643 polyps identified accordingly were re-evaluated histopathologically. Mean age of all patients was 55 years (range: 20-94); mean polyp size was 9 mm. Among these 643 polyps, 223 (34.6%) were neoplastic: I. Non-neoplastic polyps (n = 420; 65.4%) were smaller (mean: 4.1 mm), occurred in younger patients (mean: 52 years). This group consisted of fibromyoglandular polyps (n = 196) per the updated classification, cholesterol polyps (n = 166), polypoid pyloric gland metaplasia (n = 41) and inflammatory polyps (n = 17). II. Neoplastic polyps were larger (mean: 21 mm), detected in older patients (mean: 61 years) and consisted of intra-cholecystic neoplasms (WHO's "adenomas" and "intracholecystic papillary neoplasms", ≥1 cm; n = 120), their "incipient" version (<1 cm) (n = 44), polypoid invasive carcinomas (n = 26) and non-neoplastic polyps with incidental dysplastic changes (n = 33). In terms of size cut-off correlations, overall, only 27% of polyps were ≥1 cm, 90% of which were neoplastic. All (except for one) ≥2 cm were neoplastic. However, 14% of polyps <1 cm were also neoplastic. Positive predictive value of ≥1 cm cut-off -which is widely used for cholecystectomy indication-, was 94.3% and negative predictive value was 85%.

CONCLUSIONS

Approximately a third of polypoid lesions in the cholecystectomies (regardless of the indication) prove to be neoplastic. The vast majority of (90%) of polyps ≥1 cm and virtually all of those ≥2 cm are neoplastic confirming the current impression that polyps ≥1 cm ought to be removed. However, this study also illustrates that 30% of the neoplastic polyps are <1 cm and therefore small polyps should also be closely watched, especially in older patients.

The management of gallbladder polyps

Neoplastic gallbladder polyps (NGP) are rare; the prevalence in the overall population is less than 10%. NGP are associated with a risk of malignant degeneration and must be distinguished from other benign gallbladder polypoid lesions that occur more frequently. NGP are adenomas and the main risk associated with their management is to fail to detect their progression to gallbladder cancer, which is associated with a particular poor prognosis. The conclusions of the recent European recommendations have a low level of evidence, based essentially on retrospective small-volume studies. Abdominal sonography is the first line study for diagnosis and follow-up for NGP. To prevent the onset of gallbladder cancer, or treat malignant degeneration in its early phases, all NGP larger than 10mm, or symptomatic, or larger than 6mm with associated risk factors for cancer (age over 50, sessile polyp, Indian ethnicity, or patient with primary sclerosing cholangitis) are indications for cholecystectomy. Apart from these situations, simple sonographic surveillance is recommended for at least five years; if the NGP increases in size by more than 2mm in size, cholecystectomy is indicated. Laparoscopic cholecystectomy is possible but if the surgeon feels that the risk of intra-operative gallbladder perforation is high, conversion to laparotomy should be preferred to avoid potential intra-abdominal tumoral dissemination. When malignant NGP is suspected (size greater than 15mm, signs of locoregional extension on imaging), a comprehensive imaging workup should be performed to search for liver extension: in this setting, radical surgery should be considered.

Strategy for discriminating cholesterol and premalignancy in polypoid lesions of the gallbladder: a single-centre, retrospective cohort study

BACKGROUND

The present study aimed to assess the risk factors of cholesterol and premalignancy in polypoid lesions of the gallbladder (PLGs) and to establish an appropriate treatment strategy.

METHODS

Data from patients who underwent cholecystectomy at the First Affiliated Hospital, School of Medicine, Zhejiang University, between January 2011 and July 2017, were collected retrospectively.

RESULTS

A total of 1561 patients were included in the present study. The cohort comprised of 636 (40.7%) males and 925 (59.3%) females, with a mean age of 49.5 (range 16-88) years; 65.6% (1024/1561) demonstrated cholesterol lesions in this cohort, among which cholesterol polyps accounted for 81.0%. Age younger than 50 years and multiple number of polyps were found to be independent predictive variables for cholesterol lesions (odds ratio (OR) 3.461, 95% confidence interval (CI) 2.058-5.820, P < 0.001 and OR 3.321, 95% CI 1.988-5.547, P < 0.001, respectively). The presence of polyp growth was associated with premalignancy (OR 5.366, 95% CI 1.466-19.637, P = 0.011), and the presence of clinical symptoms indicated benign non-cholesterol lesions (OR 0.368, 95% CI 0.153-0.885, P = 0.026).

CONCLUSION

In the case of patients ≥50 years old with single asymptomatic polyp, cholecystectomy was recommended if the polyp presented growth at a rate above 3-4 mm within 6 months. If not, trimonthly ultrasound follow up was recommended, and clinicians should carefully assess the risk factors for premalignancy in PLGs.