Carcinoma of the gallbladder in a population of Southwestern American Indians.

The clinical and pathological characteristics of gallbladder carcinoma were studied in a group of 56 Southwestern American Indian patients. This is the third most common malignant tumor among American Indian females in a population served by the New Mexico Tumor Registry accounting for 8.5% of specific cancer diagnoses by site. Carcinoma of the gallbladder is relatively more common within the Indian population than among Spanish Americans or Anglos living in this area. This is true for both sexes. No significant differences in average age at diagnosis, ratio of female to male patients, signs and symptoms, stage at diagnosis or survival were detected in comparison with studies pertaining to gallbladder carcinoma in non-Indian populations. A squamous cell carcinoma component was unusually common however, and carcinoma in situ or atypical adenomatous hyperplasia of the mucosa was frequently documented adjacent to invasive carcinoma. Although gall stones were present in tumor containing gallbladders in 93% of cases, elective cholecystectomy for cholelithiasis is probably not a practical means of prevention of this tumor in view of the unusual frequency of cholelithiasis in Indian women. Pharmacological conversion of bile to a non-lithogenic form may deserve consideration as prophylaxis against both cholelithiasis and carcinoma of the gallbladder in this population.