Spontaneous intestinal adenocarcinoma in geriatric macaques (Macaca sp.).

ABSTRACT

BACKGROUND AND PURPOSE: Intestinal adenocarcinoma appears to be the most common malignant neoplasm in macaques, and is a substantial cause of morbidity and mortality in the elderly. METHODS: A retrospective review of 32 cases was done. RESULTS: Thirty-two cases were reviewed. Clinical examination had revealed severe weight loss, anorexia, and palpable abdominal mass. Microcytic hypochromic anemia, intermittent fecal occult blood positive test results, hypoproteinemia, and hypoalbuminemia were the predominant clinical laboratory findings. Carcinoembryogenic antigen serologic testing and single-strand conformational polymorphism analysis were performed in selected cases. The most common sites of the intestinal adenocarcinoma were ileocecal junction, colon, ileum, jejunum, and cecum. Metastases were evident in 34% of the cases and involved peripheral nodes, liver, lungs, pancreas, and adrenal gland. Overall survival of 12 macaques that underwent surgical excision was 83% at 6 months, 58% at 1 year, 50% at 1.5 years, 33% at 2 years, and 8% at 4 years. The overall mean survival rate (MSR) was > 483 postoperative days. CONCLUSION: Intestinal adenocarcinomas should be amenable to surgical resection. Early detection of localized, non-invasive neoplasms will increase surgical cure rate. Survivability could be potentially improved by use of adjuvant therapies.