Objective: To investigate the clinicopathological features, surgical treatment and prognosis of incidental gallbladder carcinoma (IGC).
Methods: The clinical data of 37 IGC cases admitted to our hospital were retrospectively analysed, and the data were compared with other gallbalder carcinoma cases (GC group) admited over the same period of time.
Results: In both IGC and GC groups, the main symptom was abdominal pain located in the upper right quadrant (94.6% vs. 93.3%) and some patients had jaundice (16.2% vs. 31.5%). There were no significant differences between the two groups in several aspects, such as age (56±12 vs. 57±9）, proportion of female patients（78.4% vs. 62.9%）, positive  ratio  of CEA （25% vs. 32.8%）and CA19-9（30% vs. 68.3%）,tumor location,  pathological type, pathological grade, and postoperative complication rate （2.7% vs. 6.7%）（All P＞0.05）. However,  the percentage of patients with cholecystolithiassis was 86.5% in IGC group, and 50.6% in GC group (P=0.000). Besides the percentage of IA stage in IGC  group (29.7%) was relatively higher than that (9.0%)in GC group (P=0.03); the surgical resection rate of tumor in IGC group was 56.8% and 32.6% in GC group (P=0.01). Nevertheless, the percentage of advance stage in IGC group (43.2%) was relatively lower than that in GC group (74.2%) (P=0.001). The overall 1, 3, and 5-year survival rate of IGC group was 70.0%, 31.2% and 26.8% repectively, and the mean survival time was17 months (51±13); which were significantly higher than those in GC group, in  which the 1, 3, 5-year survival rate was 27.0%, 17.7% and 15.1%  repectively and the mean survival time was （25±8）,5 months (all P=0.006). Single factor analysis showed that the survival time in IGC patients was influenced by the TNM stage(P=0.000), pT-category (P=0.000), operation-category(P=0.008); however, postoperative pathological grade(P=0.080), age (P=0.188) and sex(P=0.234) had no influence on survival rate. According to multivariate analysis, pT-category（P=0.000）was an independent factor for the survival time of IGC.
Conclusions: Comparing with GC group, IGC has a higher percentage of cholecystolithiassis, IA tumor stage and surgical resection rate, and thus, it has relatively better progonosis. pT-category is the vital independent prognostic factor in IGC. If a patient in ICG has been misdiagnosed during the primary operation, the patient should be re-operated for radical excision as soon as possible, except when the tumor is in stage Tis or T1a.