From the Guidelines
Gallbladder polyps should be monitored with ultrasound at intervals determined by their size, with polyps 10mm or larger generally warranting surgical consultation for possible cholecystectomy due to increased malignancy risk. The recommended ultrasound monitoring guidelines for gallbladder polyps are as follows:
- For polyps smaller than 6mm, follow-up ultrasound is recommended every 1-2 years, as the risk of malignancy is extremely low, with no cases of gallbladder cancer (GBC) seen in polyps of 5 mm or less in a 2014 meta-analysis 1.
- For polyps 6-9mm, ultrasound monitoring should occur every 6-12 months, as the risk of malignancy increases with size, but is still relatively low, with a rate of 1.3 per 100,000 patients for those with polyps smaller than 6 mm 1.
- For polyps 10-14mm, follow-up US at 6,12, and 24 months is recommended, as the risk of malignancy increases further, with a rate of 8.7 per 100,000 patients for those with polyps at least 6 mm but smaller than 10 mm 1.
- For polyps 15mm or larger, surgical consultation is recommended, as the risk of malignancy is significantly higher, with a rate of 128 per 100,000 patients for those with polyps 10 mm or larger 1. Risk factors that may necessitate more frequent monitoring include age over 50, primary sclerosing cholangitis, rapid polyp growth (more than 4mm in 1 year), sessile polyps, and solitary polyps, as growth of up to 3 mm may be part of the natural history of nonmalignant gallbladder polyps, but growth of 4 mm or more within 1 year constitutes rapid growth 1. The monitoring schedule can be relaxed if polyps remain stable over 2-3 years, as regular ultrasound monitoring allows for early detection of concerning changes while avoiding unnecessary surgery for the majority of patients with benign, stable polyps.
From the Research
Ultrasound Monitoring Guidelines for Gallbladder Polyps
The recommended ultrasound (u/s) monitoring guidelines for gallbladder polyps are as follows:
- Primary investigation of polypoid lesions of the gallbladder should be with abdominal ultrasound 2.
- Cholecystectomy is recommended in patients with polypoid lesions of the gallbladder measuring 10 mm or more, providing the patient is fit for, and accepts, surgery 2, 3.
- If the patient has a 6-9 mm polypoid lesion of the gallbladder and one or more risk factors for malignancy, cholecystectomy is recommended if the patient is fit for, and accepts, surgery 2.
- Follow-up ultrasound of the gallbladder is recommended at 6 months, 1 year, and 2 years for patients with gallbladder polypoid lesions of 6-9 mm and no risk factors for malignancy, or risk factors for malignancy and a gallbladder polypoid lesion 5 mm or less 2.
- If the patient has no risk factors for malignancy, and a gallbladder polypoid lesion of 5 mm or less, follow-up is not required 2.
- If during follow-up the gallbladder polypoid lesion grows to 10 mm, then cholecystectomy is advised 2.
- If during follow-up the gallbladder polypoid lesion disappears, then monitoring can be discontinued 2.
Risk Factors for Malignancy
Risk factors for malignancy include:
- Age more than 60 years 2
- History of primary sclerosing cholangitis (PSC) 2
- Asian ethnicity 2
- Sessile polypoid lesion (including focal gallbladder wall thickening > 4 mm) 2
- Symptoms potentially attributable to the gallbladder 2, 3
Alternative Imaging Modalities
Alternative imaging modalities, such as contrast-enhanced and endoscopic ultrasound, may be useful to aid decision-making in difficult cases, but are not recommended for routine use 2, 3, 4.
Longitudinal Ultrasound Assessment
Longitudinal ultrasound assessment of changes in size and number of incidentally detected gallbladder polyps has shown that polyps can fluctuate in size, number, and visibility over serial examinations 5.
Projected Benefits of Ultrasound Surveillance
Projected benefits of ultrasound surveillance of small, incidentally detected gallbladder polyps are limited, with estimated life expectancy gains of less than 3 days across most cohorts and scenarios evaluated 6.