Colon cancer in aged captive rhesus monkeys (Macaca mulatta)

Area of Science:

• Veterinary Pathology
• Comparative Oncology
• Primate Aging Studies

Background:

• Aging is associated with increased cancer risk in many species.
• Nonhuman primates serve as valuable models for human diseases.
• Understanding age-related neoplasia in primates informs comparative pathology.

Purpose of the Study:

• To investigate the age-related incidence of malignant neoplasia in rhesus monkeys.
• To specifically examine the prevalence and characteristics of colon cancer in aged rhesus monkeys.
• To compare colon cancer development in rhesus monkeys to that observed in humans.

Main Methods:

• Retrospective analysis of 301 necropsy cases from rhesus monkeys aged 13-37 years.
• Data collected from the Wisconsin Regional Primate Research Center over 15 years.
• Histopathological examination and location mapping of identified malignant neoplasms, focusing on colon cancer.

Main Results:

• Fifty-one malignant neoplasms were identified; 25 were colon cancers.
• Colon cancer incidence increased with age, ranging from 3.2% (13-19 years) to 20.7% (30-37 years).
• Most colon cancers were mucinous adenocarcinomas, primarily unicentric in the cecum and transverse colon, with limited metastasis.

Conclusions:

• Colon cancer is a common outcome of aging in rhesus monkeys.
• The age-related incidence of colon cancer in rhesus monkeys parallels findings in human populations.
• Rhesus monkeys represent a relevant model for studying age-associated colon cancer development.