Hereditary nonpolyposis colorectal cancer

Colorectal cancer (CRC) is the 2nd most common cancer in Germany (incident cases >70,000 persons each year). In 15-25% of all cases, a positive family history is present, and in 2-5% there is a monogenetic background. The most common form of hereditary CRC is hereditary nonpolyposis colorectal cancer (HNPCC) syndrome (also called Lynch syndrome). The cumulative lifetime risk for the development of tumours is 80%. In addition to an increased CRC risk, patients have an increased risk of developing extracolonic cancers. Through identification of the genetic background, at-risk individuals have the chance nowadays to learn their individual risk before they develop malignancies. This article reviews the clinical characteristics, genetics, diagnostic criteria, differential diagnosis, tumour risk, surveillance programmes, and distinct therapeutic aspects. © 2010 Springer Medizin Verlag.