The study, led by Dr Karl Hemminki, found that 1,113 of the patients received a diagnosis of second colorectal cancer.
The relative risk of all second colorectal cancers was 2.2 times greater than the risk of first cancers.
Patients with familial colorectal cancers were twice as likely to develop a second cancer than patients with sporadic forms.
Familial colorectal cancer was associated with an increased risk of small-intestinal, endometrial, and gastric cancers. These malignancies are all typical of hereditary nonpolyposis colorectal cancer (HNPCC).
|Age of onset is most important covariate of second colorectal cancers.|
|Cancer Epidemiology Biomarkers and Prevention|
The research, published in Cancer Epidemiology Biomarkers and Prevention, found that age of onset of first colorectal cancer was an important determinant of the risk of subsequent cancers.
The risk of second cancer for patients aged 15-39 was 27-times greater than the risk of developing a first cancer.
Dr Hemminki concludes, "The high risk of second cancer after early onset colorectal cancer calls for evaluation of family history and clinical surveillance."