RESUMO
IMPORTANCE: Hereditary cancer syndromes infer high cancer risks and require intensive cancer surveillance, yet the prevalence and spectrum of these conditions among unselected patients with early-onset colorectal cancer (CRC) is largely undetermined. OBJECTIVE: To determine the frequency and spectrum of cancer susceptibility gene mutations among patients with early-onset CRC. DESIGN, SETTING, AND PARTICIPANTS: Overall, 450 patients diagnosed with colorectal cancer younger than 50 years were prospectively accrued from 51 hospitals into the Ohio Colorectal Cancer Prevention Initiative from January 1, 2013, to June 20, 2016. Mismatch repair (MMR) deficiency was determined by microsatellite instability and/or immunohistochemistry. Germline DNA was tested for mutations in 25 cancer susceptibility genes using next-generation sequencing. MAIN OUTCOMES AND MEASURES: Mutation prevalence and spectrum in patients with early-onset CRC was determined. Clinical characteristics were assessed by mutation status. RESULTS: In total 450 patients younger than 50 years were included in the study, and 75 gene mutations were found in 72 patients (16%). Forty-eight patients (10.7%) had MMR-deficient tumors, and 40 patients (83.3%) had at least 1 gene mutation: 37 had Lynch syndrome (13, MLH1 [including one with constitutional MLH1 methylation]; 16, MSH2; 1, MSH2/monoallelic MUTYH; 2, MSH6; 5, PMS2); 1 patient had the APC c.3920T>A, p.I1307K mutation and a PMS2 variant; 9 patients (18.8%) had double somatic MMR mutations (including 2 with germline biallelic MUTYH mutations); and 1 patient had somatic MLH1 methylation. Four hundred two patients (89.3%) had MMR-proficient tumors, and 32 patients (8%) had at least 1 gene mutation: 9 had mutations in high-penetrance CRC genes (5, APC; 1, APC/PMS2; 2, biallelic MUTYH; 1, SMAD4); 13 patients had mutations in high- or moderate-penetrance genes not traditionally associated with CRC (3, ATM; 1, ATM/CHEK2; 2, BRCA1; 4, BRCA2; 1, CDKN2A; 2, PALB2); 10 patients had mutations in low-penetrance CRC genes (3, APC c.3920T>A, p.I1307K; 7, monoallelic MUTYH). Importantly, 24 of 72 patients (33.3%) who were mutation positive did not meet established genetic testing criteria for the gene(s) in which they had a mutation. CONCLUSIONS AND RELEVANCE: Of 450 patients with early-onset CRC, 72 (16%) had gene mutations. Given the high frequency and wide spectrum of mutations, genetic counseling and testing with a multigene panel could be considered for all patients with early-onset CRC.
Assuntos
Neoplasias Colorretais/genética , Predisposição Genética para Doença/epidemiologia , Predisposição Genética para Doença/genética , Síndromes Neoplásicas Hereditárias/epidemiologia , Síndromes Neoplásicas Hereditárias/genética , Adulto , Idade de Início , Mutação em Linhagem Germinativa , Humanos , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , PrevalênciaRESUMO
Outpatient colonoscopy has been proven safe but can rarely be associated with serious complications. The addition of polypectomy to the procedure increases the incidence of all complications with hemorrhage accounting for approximately half. The use of electrocautery for hot biopsy or polyp removal can result in a full-thickness burn without perforation in approximately 1 per cent of cases and typically presents as focal peritonitis without pneumoperitoneum. This so-called "postpolypectomy syndrome" or "serositis" is often successfully managed medically with resolution of symptoms in 24 to 48 hours. Bowel perforation occurs in less than 1 per cent of patients but requires emergent laparotomy. Appendicitis, both acute and perforated, has been reported as a rare complication of colonoscopy.
