Abstract and Introduction
Abstract
Background. Preoperative predictors of incidental gallbladder cancer (iGBC) have been poorly defined despite the frequency with which cholecystectomy is performed. The objective of this study was to define the incidence of and consider risk factors for iGBC at cholecystectomy.
Methods. The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database (2005–2009) was used to identify all patients who underwent cholecystectomy (N = 91,260). Patients with an International Classification of Diseases, Ninth Revision, diagnosis of gallbladder malignancy who underwent a laparoscopic cholecystectomy (LC; n = 80,924) or open cholecystectomy (OC; n = 10,336) alone were included.
Results. The incidence of iGBC was 0.19% (n = 170) for all cholecystectomy cases, but 0.05% at LC, 0.60% at LC converted to OC (P < 0.001 vs LC), and 1.13% at OC (P < 0.001 vs others). Patients undergoing OC were 17.3 times more likely to have iGBC than LC patients. Age 65 years or older, Asian or African American race, ASA (American Society of Anesthesiologists) class 3 or more, diabetes mellitus, hypertension, weight loss more than 10%, alkaline phosphatase levels 120 units/L or more, and albumin levels 3.6 g/dL or less were associated with iGBC. Multiple logistic regression identified having an OC, age 65 years or older, Asian or African American race, an elevated alkaline phosphatase level, and female sex as independent risk factors. Patients with 1, 2, 3, and 4 of these factors had a 6.3-, 16.7-, 30.0-, and 47.4-fold risk of iGBC, respectively, from a zero-risk factor baseline of 0.03%.
Conclusions. Surgeons' suspicion for GBC should be heightened when they are performing or converting from LC to OC and when patients are older, Asian or African American, female, and have an elevated alkaline phosphatase level.
Introduction
Cholecystectomy is one of the most common surgical procedures, with nearly 1 million laparoscopic cholecystectomy (LC) cases performed in the United States each year. As the safety of LC has been demonstrated, the procedure is being performed on younger patients, approximately 20% of whom do not have demonstrated cholelithiasis. This increase in LC combined with advances in imaging has led to earlier detection of gallbladder cancer (GBC). However, the US prevalence of this malignancy remains stable at 2 per 100,000 people and 8500 new cases are diagnosed annually. Classical surgical teaching has been that 1 of every 100 cholecystectomy cases (1%) has undiagnosed GBC, although 10,000 new cases of incidental GBC (iGBC) are not diagnosed each year. Despite earlier detection, recent reported rates of iGBC after LC have been estimated to be between 0.2% and 2.1%. Nevertheless, the true rate of iGBC is unknown.
Recent studies have revealed an increase in the diagnosis of iGBC, with approximately 50% of all new GBC cases detected incidentally at cholecystectomy. In patients presenting after the diagnosis of iGBC, data have shown that many of these patients will have residual disease. Furthermore, survival may be worse for certain patients with iGBC who do not undergo an R0 resection at their initial operation. With the increased frequency of cholecystectomy and potentially poorer prognosis for patients with residual disease at reoperation for iGBC, preoperative diagnosis of GBC has become increasingly important.
To detect GBC before cholecystectomy, patients at an increased risk for iGBC need to be identifiable. Local factors such as the presence of gallstones, inflammation, calcification, an abnormal pancreatobiliary junction, and polyps have been identified as risk factors for GBC. In addition, older age, female sex, and obesity are known to be associated with GBC. People of Hispanic ethnicity and Native Americans are also believed to be at an increased risk for developing GBC. In addition, various geographical regions, such as Chile, northern India, and both the southwest and the Appalachian regions of the United States, are known to have a higher prevalence of GBC. Although several known risk factors for GBC exist, many of these have been based on epidemiological data, radiographic findings, or smaller series of patients with advanced tumors and not on incidentally discovered cancers. Therefore, the aims of this study were to define the incidence of and consider risk factors for iGBC at cholecystectomy in North America.