Determining the extent of cholecystectomy using intraoperative specimen ultrasonography in patients with suspected early gallbladder cancer

Abstract

Background: Accumulating evidence and guidelines recommend extended cholecystectomy for T1b or greater gallbladder cancers. This study aimed to evaluate the feasibility of intraoperative ultrasonography of a resected gallbladder specimen (specimen US) for the determination of the extent of cholecystectomy.

Methods: We included 45 patients (34 women; median [interquartile range] age, 66 [57-74] years) who underwent specimen US. After simple laparoscopic cholecystectomy, a gallbladder specimen was examined to evaluate the depth of tumor invasion by specimen US and frozen section examination. With the results of those two examinations, the operating surgeon decided whether to perform extended cholecystectomy. The sensitivity and specificity of specimen US and frozen section examination in diagnosing T1b or greater cancer were, respectively, measured using permanent pathology as the reference standard. The surgeons' final decisions were evaluated in the same manner as the intraoperative examinations.

Results: Among 22 patients in whom adenocarcinomas were confirmed, 17 patients had T1b or greater cancers. The sensitivity and specificity of specimen US alone were 81 % (95 % CI, 54-96 %) and 85 % (65-96 %), respectively. The sensitivity and specificity of frozen section examination alone were 43 % (10-82 %) and 95 % (75-100 %), respectively. Except one patient in whom extended cholecystectomy was intentionally not performed, 14 out of 16 patients (88 %; 95 % CI, 62-98 %) who were finally confirmed as having T1b or greater cancers underwent extended cholecystectomy by the surgeons' decision based on both specimen US and frozen examination. Out of 28 patients who were finally confirmed as having benign lesions or T1a cancers, 25 (89 %; 72-98 %) underwent simple cholecystectomy.

Conclusion: Specimen US was feasible to be incorporated in clinical practice. Although the diagnostic accuracy of specimen US alone was moderate, the combined use of specimen US and frozen section examination could help the surgeons make correct decisions on the extent of cholecystectomy.

Keywords: Feasibility studies; Gallbladder; Gallbladder neoplasms; Neoplasm staging; Ultrasonography.