Physics

Internal medicine

Pediatrics

Family history

Population

Colorectal cancer

Incidence (geometry)

Biology

Gene

Optics

Cancer

Proband

Mutation

Genetics

Medicine

Environmental health

Medical and Pediatric Oncology

Background Family history of colorectal cancer among adult patients has been reported in the literature. Although extremely rare in children, colorectal cancer in this population may represent a unique group in whom genetic factors play a significant etiologic role. The aim of the present study was to assess genetic contribution, as measured by family history, to the development of colorectal cancer in probands under 21 years of age at diagnosis. Procedure Detailed family histories were obtained from surviving patients or their parents. The risk [standardized incidence ratio (SIR)] of cancer in the relatives was calculated by comparing the observed and the expected incidence based on rates in the general population and person-years at risk. Results Twenty-five patients (median age at diagnosis 15 years) diagnosed with colorectal cancer at St. Jude Children's Research Center since 1964 or their surviving next of kin were available for interview. The 461 relatives contributed 18,908 person-years of follow-up. Statistically significant increased risk of colorectal cancer was present among all relatives (SIR = 6.0, 95% CI, 2.7–10.6), and the increased risk of colorectal cancer was confined to relatives of probands who were under 15 years of age at diagnosis (SIR = 10.0, 95% CI, 4.5–17.6). In addition, there was an excess of uterine/cervical cancer among all female relatives (SIR = 6.5, 95% CI, 3.2–10.9). Conclusions The observed excess of colorectal cancer, in relatives of younger probands, suggests the need to examine these kindreds for genetic instability resulting from defects in mismatch repair genes to characterize further the patterns of risk observed. Med. Pediatr. Oncol. 33:470–475, 1999. © 1999 Wiley-Liss, Inc.

Family history of cancer in children and young adults with colorectal cancer