The risk of developing invasive colorectal cancer (CRC) is similar between people with a family history of colorectal carcinoma in situ (CCIS) and those with a family history of invasive CRC, according to a study published in the Journal of the National Comprehensive Cancer Network.
The findings suggest that family history of CCIS should be considered similarly to family history of invasive CRC in risk stratification for earlier CRC screening, according to researchers.
The researchers used data from Swedish family cancer datasets to calculate standardized incidence ratios (SIRs) and the cumulative risk of invasive CRC in first- and second-degree relatives of people with CCIS or invasive CRC.
Of the 12.8 million individuals analyzed, 173,796 were diagnosed with CRC and 40,558 had CCIS.
The lifetime cumulative risk of invasive CRC was similar between first-degree relatives of patients with CCIS and first-degree relatives of patients with CRC — 6.5% and 6.7%, respectively (SIR, 1.6 for both).
The lifetime cumulative risk of invasive CRC was also similar between second-degree relatives of patients with CCIS or CRC — 4.6% and 5.1%, respectively (SIR, 1.2 for both).
The risk of invasive CRC between people with a family history of CCIS and those with a family history of invasive CRC remained similar when participants were stratified by sex, age at diagnosis of invasive CRC in the index person, and age at diagnosis of CCIS or CRC in the affected first-degree relative.
Based on these results, the researchers recommended the aforementioned change to CRC screening guidelines and suggested that future studies of familial risk of colorectal neoplasms include family history of CCIS.
Tian Y, Kharazmi E, Brenner H, et al. Importance of family history of colorectal carcinoma in situ versus invasive colorectal cancer: A nationwide cohort study. J Natl Compr Canc Netw. Published online September 13, 2021. doi:10.6004/jnccn.2021.7004.