Risk of colonic adenoma in patients with non–colorectal cancers.

Abstract

e13070 Background: In the last two decades, the incidence of colorectal cancer (CRC) has decreased dramatically after the implementation of CRC screening in the United States. Several risk factors for colonic adenoma (CA), the main precursor for CRC, have been found. Whether personal history of non-colorectal cancer (NCRC) is a risk factor for CA has not been studied. Here, we assess the risk of CA in patients with NCRCs. Methods: We conducted a retrospective study of cancer patients who underwent colonoscopy after cancer diagnosis between 2009 and 2018. We included patients without history of NCRC as a control group. Multivariate logistic regression was used to assess independent risk factors for CA (Table 1). Results: Total of 9408 patients with NCRC were included; CA was detected in 4503 (48%). Histology revealed tubulovillous features in 611 (14%) patients and villous in 51 (1%). High grade dysplasia was detected in 1,317 (29%) patients and adenocarcinoma in 388 (9%). The rate of adenocarcinoma was the highest in patients with multiple myeloma (14%). Adenoma detection rate (ADR) was 30% in patients younger than 40 years ( n= 1621), 32% in patients between 40 and 50 years ( n= 812), 47% in patients between 50 and 60 years ( n= 2892), and 55% in patients older than 60 years ( n= 4493). Multivariate analysis revealed an increased risk of CA with old age, male sex, family history of CRC, and high body mass index ( P< 0.05). The median time from NCRC diagnosis to CA detection was 3 years (IQR 1-8). Conclusions: ADR in patients with a personal history of NCRC is higher than the ADR of patients without NCRC. CRC screening should be performed after the diagnosis of NCRC is made, even if it was before the standard threshold of CRC screening age of 50 years.[Table: see text]