Role of laparoscopic cholecystectomy in treating gallbladder polyps

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.

Transabdominal ultrasound and endoscopic ultrasound for diagnosis of gallbladder polyps

BACKGROUND

Approximately 0.6% to 4% of cholecystectomies are performed because of gallbladder polyps. The decision to perform cholecystectomy is based on presence of gallbladder polyp(s) on transabdominal ultrasound (TAUS) or endoscopic ultrasound (EUS), or both. These polyps are currently considered for surgery if they grow more than 1 cm. However, non-neoplastic polyps (pseudo polyps) do not need surgery, even when they are larger than 1 cm. True polyps are neoplastic, either benign (adenomas) or (pre)malignant (dysplastic polyps/carcinomas). True polyps need surgery, especially if they are premalignant or malignant. There has been no systematic review and meta-analysis on the accuracy of TAUS and EUS in the diagnosis of gallbladder polyps, true gallbladder polyps, and (pre)malignant polyps.

OBJECTIVES

To summarise and compare the accuracy of transabdominal ultrasound (TAUS) and endoscopic ultrasound (EUS) for the detection of gallbladder polyps, for differentiating between true and pseudo gallbladder polyps, and for differentiating between dysplastic polyps/carcinomas and adenomas/pseudo polyps of the gallbladder in adults.

SEARCH METHODS

We searched the Cochrane Library, MEDLINE, Embase, Science Citation Index Expanded, and trial registrations (last date of search 09 July 2018). We had no restrictions regarding language, publication status, or prospective or retrospective nature of the studies.

SELECTION CRITERIA

Studies reporting on the diagnostic accuracy data (true positive, false positive, false negative and true negative) of the index test (TAUS or EUS or both) for detection of gallbladder polyps, differentiation between true and pseudo polyps, or differentiation between dysplastic polyps/carcinomas and adenomas/pseudo polyps. We only accepted histopathology after cholecystectomy as the reference standard, except for studies on diagnosis of gallbladder polyp. For the latter studies, we also accepted repeated imaging up to six months by TAUS or EUS as the reference standard.

DATA COLLECTION AND ANALYSIS

Two authors independently screened abstracts, selected studies for inclusion, and collected data from each study. The quality of the studies was evaluated using the QUADAS-2 tool. The bivariate random-effects model was used to obtain summary estimates of sensitivity and specificity, to compare diagnostic performance of the index tests, and to assess heterogeneity.

MAIN RESULTS

A total of 16 studies were included. All studies reported on TAUS and EUS as separate tests and not as a combination of tests. All studies were at high or unclear risk of bias, ten studies had high applicability concerns in participant selection (because of inappropriate participant exclusions) or reference standards (because of lack of follow-up for non-operated polyps), and three studies had unclear applicability concerns in participant selection (because of high prevalence of gallbladder polyps) or index tests (because of lack of details on ultrasound equipment and performance). A meta-analysis directly comparing results of TAUS and EUS in the same population could not be performed because only limited studies executed both tests in the same participants. Therefore, the results below were obtained only from indirect test comparisons. There was significant heterogeneity amongst all comparisons (target conditions) on TAUS and amongst studies on EUS for differentiating true and pseudo polyps.Detection of gallbladder polyps: Six studies (16,260 participants) used TAUS. We found no studies on EUS. The summary sensitivity and specificity of TAUS for the detection of gallbladder polyps was 0.84 (95% CI 0.59 to 0.95) and 0.96 (95% CI 0.92 to 0.98), respectively. In a cohort of 1000 people, with a 6.4% prevalence of gallbladder polyps, this would result in 37 overdiagnosed and seven missed gallbladder polyps.Differentiation between true polyp and pseudo gallbladder polyp: Six studies (1078 participants) used TAUS; the summary sensitivity was 0.68 (95% CI 0.44 to 0.85) and the summary specificity was 0.79 (95% CI 0.57 to 0.91). Three studies (209 participants) used EUS; the summary sensitivity was 0.85 (95% CI 0.46 to 0.97) and the summary specificity was 0.90 (95% CI 0.78 to 0.96). In a cohort of 1000 participants with gallbladder polyps, with 10% having true polyps, this would result in 189 overdiagnosed and 32 missed true polyps by TAUS, and 90 overdiagnosed and 15 missed true polyps by EUS. There was no evidence of a difference between the diagnostic accuracy of TAUS and EUS (relative sensitivity 1.06, P = 0.70, relative specificity 1.15, P = 0.12).Differentiation between dysplastic polyps/carcinomas and adenomas/pseudo polyps of the gallbladder: Four studies (1,009 participants) used TAUS; the summary sensitivity was 0.79 (95% CI 0.62 to 0.90) and the summary specificity was 0.89 (95% CI 0.68 to 0.97). Three studies (351 participants) used EUS; the summary sensitivity was 0.86 (95% CI 0.76 to 0.92) and the summary specificity was 0.92 (95% CI 0.85 to 0.95). In a cohort of 1000 participants with gallbladder polyps, with 5% having a dysplastic polyp/carcinoma, this would result in 105 overdiagnosed and 11 missed dysplastic polyps/carcinomas by TAUS and 76 overdiagnosed and seven missed dysplastic polyps/carcinomas by EUS. There was no evidence of a difference between the diagnostic accuracy of TAUS and EUS (log likelihood test P = 0.74).

AUTHORS' CONCLUSIONS

Although TAUS seems quite good at discriminating between gallbladder polyps and no polyps, it is less accurate in detecting whether the polyp is a true or pseudo polyp and dysplastic polyp/carcinoma or adenoma/pseudo polyp. In practice, this would lead to both unnecessary surgeries for pseudo polyps and missed cases of true polyps, dysplastic polyps, and carcinomas. There was insufficient evidence that EUS is better compared to TAUS in differentiating between true and pseudo polyps and between dysplastic polyps/carcinomas and adenomas/pseudo polyps. The conclusions are based on heterogeneous studies with unclear criteria for diagnosis of the target conditions and studies at high or unclear risk of bias. Therefore, results should be interpreted with caution. Further studies of high methodological quality, with clearly stated criteria for diagnosis of gallbladder polyps, true polyps, and dysplastic polyps/carcinomas are needed to accurately determine diagnostic accuracy of EUS and TAUS.

Gallbladder Polyps

Most small gallbladder polyps are benign and do not change significantly over time. They are usually incidental findings on ultrasound. Therefore, these polyps should be checked periodically with routine percutaneous ultrasonography. In the asymptomatic patient, gallbladder polyps that are greater than 1 cm in diameter should be treated with cholecystectomy. The size of the polyp and the patient greater than 50 years are important risk factors for malignant potential. Patients who have biliary pain and small gallbladder polyps without gallstones present a difficult management decision for the clinician. If the physician is confident that the polyps are the source of the pain, patients should be referred for cholecystectomy. Endoscopic ultrasound and positron emission tomography may prove to be useful in assessing the malignant potential of large gallbladder polyps. Laparoscopic cholecystectomy is the treatment of choice for most gallbladder polyps. If a malignant polyp is suspected, patients should undergo an open cholecystectomy.

Polypoid lesions of the gallbladder

BACKGROUND

Polypoid lesions of the gallbladder encompass a wide variety of pathology. Although most of these lesions are benign, some early carcinomas of the gallbladder do present as polypoid lesions. Problems remain in selecting patients with polypoid lesions of the gallbladder for surgery, the operative approach, and the method of follow-up of those deemed not needing surgery.

DATA SOURCES

This review was done by Medline search of the English literature by the keywords "polypoid lesions of gallbladder," "gallbladder polyps," "carcinoma of gallbladder," and "benign tumors of gallbladder."

CONCLUSIONS

Most small polypoid lesions of the gallbladder are benign and remain static for years. Three- to six-monthly ultrasonography examination is warranted in the initial follow-up period but it is probably unnecessary after 1 or 2 years. Age more than 50 years and size of polyp more than 1 cm are the two most important factors predicting malignancy in polypoid lesions of the gallbladder. Other risk factors include concurrent gallstones, solitary polyp, and symptomatic polyp. Laparoscopic cholecystectomy is the treatment of choice unless the suspicion of malignancy is high, in which case it is advisable to have open exploration, intraoperative frozen section, and preparation for extended resection.

Late follow-up of polypoid lesions of the gallbladder smaller than 10 mm

OBJECTIVE

To determine the variation in number, size, and symptoms in patients with polypoid lesions of the gallbladder.

SUMMARY BACKGROUND DATA

A polypoid lesion is any elevated lesion of the gallbladder mucosa. Several studies have been reported in patients undergoing cholecystectomy, but little information exits regarding the natural history of these lesions in nonoperated patients.

METHODS

A total of 111 patients with ultrasound diagnosis of polypoid lesions smaller than 10 mm were followed up by clinical evaluation and ultrasonography. Twenty-seven patients underwent cholecystectomy.

RESULTS

There was no difference in terms of gender. Nearly 80% of the lesions were smaller than 5 mm; they were single in 74%. In nonoperated patients, 50% remained of similar size at the late follow-up, 26.5% increased in number and size, and 23.5% shrank or disappeared. Among the operated patients, 70% corresponded to cholesterol polyps. None of the patients developed symptoms of biliary disease or gallstones or adenocarcinoma.

CONCLUSIONS

Ultrasound is useful in the follow-up of patients with polypoid lesions of the gallbladder. Lesions smaller than 10 mm do not progress to malignancy or to development of stones, and none produced symptoms or complications of biliary disease.

Role of laparoscopic cholecystectomy in the management of polypoid lesions of the gallbladder

This retrospective clinicohistopathologic study was performed to delineate the role of laparoscopic cholecystectomy in the management of polypoid lesions of the gallbladder. One hundred forty-three consecutive patients who had a preoperative sonographic diagnosis of polypoid lesions of the gallbladder with a diameter less than 1.5 cm and who underwent laparoscopic cholecystectomy at Cathay General Hospital were included in the analysis. Histopathologic study showed that 22 (15.4%) patients had true tumors, including adenoma (16), adenoma with focal adenocarcinoma (2), adenocarcinoma (3), and carcinoid tumor (1). Tumorlike lesions were found in 121 (84.6%) patients and included cholesterol polyp (106), adenomyomatous hyperplasia (10), inflammatory polyp (3), and papillary hyperplasia (2). The mean diameter of malignant polypoid lesions of the gallbladder was 1.35 +/- 0.42 cm, which was significantly larger than that of cholesterol polyps (0.66 +/- 0.40 cm, P = 0.0001) but not significantly larger than that of adenomyomatous hyperplasias (1.12 +/- 0.42 cm) and adenomas (1.08 +/- 0.47 cm). The mean age of patients with malignant polypoid lesions of the gallbladder (61.2 +/- 13.3 years old) was significantly older than that of patients with adenomyomatous hyperplasia (46.6 +/- 13.4 years, P = 0.03), cholesterol polyps (44.5 +/- 10.5 years, P = 0.0003), and adenomas (41.4 +/- 9.4 years, P = 0.0008). Clinical follow-up showed that most (98.6%) patients benefited from the minimal invasiveness of laparoscopic cholecystectomy with satisfactory surgical results. We conclude that laparoscopic cholecystectomy is a reliable, safe, and minimally invasive biopsy procedure and definite management of polypoid lesions of the gallbladder with a diameter less than 1.5 cm.

Isolated Small Gallbladder Polyps: An Indication for Cholecystectomy in Symptomatic Patients

To evaluate patients with gallbladder polyps and to compare them with patients with chronic acalculous cholecystitis, 301 patients with chronic acalculous disease of the gallbladder, of which 45 had polyp disease of the gallbladder, were reviewed out of 7181 cholecystectomies performed from June 1985 through June 1995. Of the 45 patients, 30 (Group A) were diagnosed preoperatively by ultrasound and 15 (Group B) postoperatively on pathologic examination. In each group, the most common polyp was cholesterol type (19/45) with multiple lesions in 10 of these 19 patients. Chronic cholecystitis was present elsewhere in the gallbladder in 40 per cent of Group A and 80 per cent of Group B patients ( P = 0.02). Forty-three patients had polyps less than 5 mm in diameter, one a 1.5-cm gallbladder cholesterol polyp, and one a 1.3-cm tubulovillous polyp with a focus of carcinoma in situ. During this same period, 17 patients had primary malignancy of the gallbladder, none of which were found in polypoid lesions. In Group A patients there were significantly fewer preoperative tests than in typical acalculous patients [2.3 versus 3.8 ( P < 0.03)], including upper endoscopy ( P < 0.02) and hepatobiliary scintigraphy ( P < 0.00001). Of the patients with polyps, 42 of 45 (93.3%) had resolution of symptoms postoperatively with a mean follow-up of 178.9 ± 505.0 days (range 1–2438 days). Most patients with biliary tract symptoms and a small (<5-mm) gallbladder polyp underwent fewer preoperative diagnostic tests than patients with chronic acalculous cholecystitis. This abbreviated preoperative workup appears warranted in view of the high incidence of symptom resolution.

Superficial elevated-type early gallbladder carcinoma treated by laparoscopic cholecystectomy

A 60-year-old woman was admitted to our department for detailed examination of a polypoid lesions of the gallbladder detected at the time of a mass survey by ultrasound. Endoscopic ultrasonography (EUS) demonstrated a broad-based mass lesion, about 10 mm in size, with an irregular surface, at the peritoneal side of the body of the gallbladder. The layer structure of the gallbladder wall had not been destroyed by the mass. Computed tomography showed no direct invasion of the liver or other evidence of metastasis. Type-IIa (superficial elevated-type) early gallbladder cancer was suspected and laparoscopic cholecystectomy was performed. Histologically, the tumor proved to be a papillo-tubular adenocarcinoma, 9 x 8 mm in size, confined to the mucosa and without lymphatic permeation, vascular involvement, perineural invasion, or other signs of metastasis. Laparoscopic cholecystectomy for gallbladder cancer can be indicated only when a lesion is a pedunculated protruded-type (type-Ip) cancer, or a broad-based cancer 10 mm or less in size located on the peritoneal side with no destruction of the layer structure of the wall demonstrated by EUS. This strategy is justified only with precise evaluation of the lesion by EUS.

Reliability of frozen section diagnosis of gallbladder tumor for detecting carcinoma and depth of its invasion

BACKGROUND

An accurate frozen section diagnosis is important when deciding the surgical strategy against a gallbladder tumor intraoperatively. Little has been reported on the accuracy of frozen section diagnosis of the gallbladder.

PATIENTS AND METHODS

In a total of 86 consecutive patients with gallbladder tumor, the accuracy of the frozen section diagnosis was examined. There were 32 patients with polypoid lesions and 54 with nonpolypoid tumors.

RESULTS

The frozen tissue diagnosis and final diagnosis were identical in 82 of the 86 cases, that is, benign in 65 and malignant in 17. The other four cases had different diagnoses, that is, conversion from benign to malignant in two and from malignant to benign in two. The overall accuracy of frozen diagnosis was 95.3% (97.0% for benign and 94.7% for malignant). In 32 polypoid lesions, the accuracy of frozen section diagnosis was 91% (93% for benign; 89% for malignant). In 54 nonpolypoid lesions, the accuracy of diagnosis was 98% (100% for benign; 93% for malignant). The diagnosis of depth of invasion was identical only in 7 (70%) of the 10 carcinoma cases examined, while it was diverse in the remaining 3, that is, conversion from adenocarcinoma invading the subserosa to that limiting to the mucosa in one, from carcinoma within the mucosa to that infiltrating the muscle coat in one, and from carcinoma affecting the muscle layer to that invading the subserosa in the other. Alterations of frozen section diagnosis about being benign or malignant and about the depth of invasion were encountered in seven patients, five of whom had a polypoid tumor.

CONCLUSIONS

The intraoperative frozen tissue diagnosis is fairly reliable as to whether lesions are malignant or benign; however, accuracy is low in patients with polypoid lesions of the gallbladder. Also, frozen section diagnosis does not reliably measure the depth of invasion of gallbladder carcinoma.

Reliability of frozen section diagnosis of gallbladder tumor for detecting carcinoma and depth of its invasion

BACKGROUND

An accurate frozen section diagnosis is important when deciding the surgical strategy against a gallbladder tumor intraoperatively. Little has been reported on the accuracy of frozen section diagnosis of the gallbladder.

PATIENTS AND METHODS

In a total of 86 consecutive patients with gallbladder tumor, the accuracy of the frozen section diagnosis was examined. There were 32 patients with polypoid lesions and 54 with nonpolypoid tumors.

RESULTS

The frozen tissue diagnosis and final diagnosis were identical in 82 of the 86 cases, that is, benign in 65 and malignant in 17. The other four cases had different diagnoses, that is, conversion from benign to malignant in two and from malignant to benign in two. The overall accuracy of frozen diagnosis was 95.3% (97.0% for benign and 94.7% for malignant). In 32 polypoid lesions, the accuracy of frozen section diagnosis was 91% (93% for benign; 89% for malignant). In 54 nonpolypoid lesions, the accuracy of diagnosis was 98% (100% for benign; 93% for malignant). The diagnosis of depth of invasion was identical only in 7 (70%) of the 10 carcinoma cases examined, while it was diverse in the remaining 3, that is, conversion from adenocarcinoma invading the subserosa to that limiting to the mucosa in one, from carcinoma within the mucosa to that infiltrating the muscle coat in one, and from carcinoma affecting the muscle layer to that invading the subserosa in the other. Alterations of frozen section diagnosis about being benign or malignant and about the depth of invasion were encountered in seven patients, five of whom had a polypoid tumor.

CONCLUSIONS

The intraoperative frozen tissue diagnosis is fairly reliable as to whether lesions are malignant or benign; however, accuracy is low in patients with polypoid lesions of the gallbladder. Also, frozen section diagnosis does not reliably measure the depth of invasion of gallbladder carcinoma.

Appraisal of intraoperative ultrasonography during laparoscopic cholecystectomy

BACKGROUND

The usefulness of intraoperative ultrasonography during laparoscopic cholecystectomy (LC) has yet to be evaluated fully.

METHODS

In 50 patients who underwent LC, the intraoperative ultrasonography findings were compared with those of preoperative ultrasonography, intraoperative cholangiography, and histology, and then its usefulness for examining anatomic relationships in the hepatoduodenal ligament, detecting bile duct stones, diagnosing gallbladder polyps and abnormally thickened walls, and determining the propriety of LC was appraised.

RESULTS

The preoperative ultrasonography diagnoses were gallstones in 38 patients, polyps in 10, and cancer and adenomyomatosis in one each. In four patients endoscopic retrograde cholangiography showed bile duct stones. In all 50 patients intraoperative ultrasonography was useful for examining the anatomic relationships between the bile duct and vessels, such as the portal vein and hepatic artery, and showing the presence or absence of bile duct stones. On the basis of the intraoperative ultrasonography findings, gallstones were diagnosed in 38 patients, in five of whom bile duct stones were shown clearly, cholesterol polyps in eight, early-stage cancer or adenoma in two, and adenomyomatosis in two, and subsequently LC was performed. Histologic diagnoses of cholesterol polyps were made in eight of ten patients with polyps, and intramucosal cancer and an inflammatory polyp in one each. In one patient with a preoperative diagnosis of cancer the apparently elevated flat lesion was found to be partial thickening of the gallbladder wall, which was diagnosed as adenomyomatosis, and LC was chosen as the operative procedure.

CONCLUSIONS

Intraoperative ultrasonography during LC is useful for detecting bile duct stones, diagnosing gallbladder polyps and abnormally thickened walls, and deciding whether LC is adequate for resection of the gallbladder.

How should polypoid lesions of the gallbladder be treated in the era of laparoscopic cholecystectomy?

BACKGROUND

Definitive criteria for choosing the most appropriate treatment for each type of polypoid lesion of the gallbladder (PLG) have yet to be established.

METHODS

The shapes, sizes, echo patterns, and echogenicities of PLGs that had been evaluated by means of ultrasonography in 72 patients who had undergone resective surgery were analyzed retrospectively to elucidate the ultrasonic characteristics of polypoid cancers and to establish criteria for selecting the most suitable treatment such as laparoscopic cholecystectomy for each type of PLG.

RESULTS

Histologic examinations showed cholesterol polyps in 47 patients, adenomas in 8, cancers in 16, and an inflammatory polyp in 1. The diameters of 61% of the benign PLGs were less than 10 mm, whereas those of 88% of the cancers were more than 10 mm; 80% of the former were pedunculated and 56% of the latter were sessile. Seven of eight early-stage cancers had diameters less than 18 mm, whereas those of all eight more advanced cancers were greater than 18 mm. Five of the eight early-stage cancers were pedunculated, and six of the eight more advanced cancers were sessile. Cholecystectomy with or without full-thickness dissection were main surgical procedures used to resect benign PLGs and early-stage cancers, whereas cholecystectomy with partial liver resection was used for more advanced cancers. Laparoscopic cholecystectomy was performed in the recent 34 patients, four of whom had early-stage cancers.

CONCLUSIONS

A PLG with a diameter of less than 18 mm is a potential early-stage cancer and therefore can be resected by laparoscopic cholecystectomy with full-thickness dissection. However, when cancer invades the subserosal layer or beyond, a second-look operation is necessary. A PLG with a diameter of greater than 18 mm may be an advanced cancer and should be removed by using cholecystectomy with partial liver resection or a more extended procedure with lymph node dissection.