Hereditary nonpolyposis colon cancer: genetic basis, testing, and patient-care issues.

PURPOSE/OBJECTIVES: To describe the general mechanisms of cancer development and the specific genetic basis for hereditary nonpolyposis colon cancer (HNPCC); to discuss methods of genetic testing, surveillance, and management guidelines; and to review relevant psychosocial issues.

DATA SOURCES

Published papers, research reports, and books.

DATA SYNTHESIS

Colorectal cancer is one of the most common neoplasms in humans and perhaps the most frequent form of hereditary neoplasia. HNPCC has an autosomal dominant pattern of inheritance with variable but high penetrance estimated to be about 90%. HNPCC underlies 0.5%-10% of all cases of colorectal cancer.

CONCLUSIONS

An understanding of the mechanisms behind the development of HNPCC is emerging, and genetic presymptomatic testing, now being conducted in research settings, soon will be available on a widespread basis for individuals identified at risk for this disease. Complex medical, nursing, legal, ethical, and psychosocial issues demand oncology nurses' attention and understanding.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses in all settings play an integral role assisting patients in (a) understanding their genetic risk status and the implications of genetic testing, (b) making decisions regarding HNPCC genetic predisposition testing, and (c) understanding the meaning of DNA test results. Nurses also may assist patients in understanding and complying with recommended surveillance and management issues.