Background: Colorectal cancer is the third leading cause of cancer mortality in Western countries. Hereditary nonpolyposis colorectal cancer is the most common type of hereditary colorectal cancer, but its incidence remains controversial, ranging from 1 to 5%.
Objective: This present prospective, multicentre, nationwide study was aimed at compiling prominent epidemiological and clinical data with respect to hereditary non-polyposis colorectal cancer and other familial colorectal cancer forms in Spain, where information is lacking.
Methods: All patients with a de-novo diagnosis of colorectal cancer and who attended between November 2000 and October 2001 in 25 hospitals all over Spain were registered. Demographic, clinical and tumour-related characteristics of probands, and detailed family history, were obtained.
Results: A total of 1872 colorectal cancer patients were included. Clinical diagnosis of hereditary non-polyposis colorectal cancer was established in 46 (2.5%) patients according to the Amsterdam II criteria. Comparison between patients fulfilling either the Amsterdam I or the Amsterdam II criteria revealed no differences with respect to demographic, clinical and tumour-related characteristics. A total of 504 (27.0%) patients had a family history of hereditary non-polyposis colorectal cancer-related neoplasm not fulfilling the Amsterdam criteria (familial colorectal cancer), while 360 (19.2%) patients fulfilled at least one of the Bethesda's criteria.
Conclusion: These clinicoepidemiological data provide a more accurate characterization of hereditary non-polyposis colorectal cancer and other familial colorectal cancer forms in Spain, with potential implications in preventive strategies.