INCIDENTAL GALLBLADDER CANCER - THE FIRST REPORT FROM SUB-SAHARAN AFRICA.

BACKGROUND: Incidental gallbladder cancer (iGBC) is found in 0.3-1.5% of cholecystectomy specimens. GBC is uncommon with significant variation amongst geographical regions and ethnic groups. Less than 100 GBC's have been reported in sub Saharan Africa, hence the need for this national audit in South Africa.

METHOD: National data was obtained from the South African NHLS for 2003-2015. 34 294 cholecystectomy specimens were included of which 239 were GBCs; 135 were iGBC.

RESULTS: iGBC incidence was 0.42% with a male:female ratio of 1:4.6. Mean age was 62.2 (range 20-88; male 64.83 and female 61.67). Indications for surgery were acute cholecystitis in 49% and biliary colic in 44%. GBC T stages were Tis 12.6%, T1a 4.4%, T1b 8.8%, T2 37.8%, T3 13.3% and Tx 22%. Lymph nodes were found in 10 patients, of which 5 were N1. R1 resection occurred in 32.6% of the cohort. Univariate analysis found female sex, chronic inflammation and the presence of dysplasia to be associated with iGBC. No association was found with surgical indication, presence of gallstones or other histological findings (polyps, xanthogranulomatous inflammation, calcification and RAS). Only female gender was associated with iGBCa after multivariate analysis.

CONCLUSION: This large series demonstrates a similar incidence of iGBC in an African cohort to those reported from more developed nations, with female gender being the most significant risk factor. Delay in presentation may explain the more advanced stage (T2 and T3) and a resultant high rate of R1 resection.