Defining New Colorectal Cancer Syndromes in a Population-based Cohort of the Disease.

Background/aim: Most known cancer syndromes confer an increased risk of more than one tumour types, and families with more than one colorectal cancer often segregate other cancers as well. The aim of this study was to examine if there is a general increased risk of other cancers in colorectal cancer families, which are defined as having two or more cases of colorectal cancer in close relatives.

Materials And Methods: The study used a detailed family history of cancer diagnoses in a cohort of more than 3,000 consecutive colorectal cancer cases. A comparison was made between families with sporadic and those with familial colorectal cancer cases. Detailed morphology data were used to find further support for putative syndromes.

Results: There were significantly more non-colorectal cancers in the family history of the familial CRC cases (p<0.001), with significantly more gastric cancers (p<0.001), prostate cancers (p<0.001), urinary bladder cancers (p<0.001) and melanomas (p=0.002), leukaemia/lymphomas (p=0.004), gynaecological cancers (p=0.007) and breast cancers (p=0.023). There was also some support for different morphological profiles for four of the five tested syndromes.

Conclusion: This study found support for a general increased risk of one or more different cancer syndromes involving families with colorectal cancer and other cancers. Further studies will define the different possible syndromes and determine the genetic background.