Complications of colonoscopy surveillance of patients with Lynch syndrome - 33 years of follow up.

BACKGROUND AND STUDY AIMS: Lynch syndrome (LS) is a hereditary autosomal dominant condition, with an increased lifetime risk of developing malignancies including colorectal cancer (CRC). Current guidelines differ in recommended colonoscopy-surveillance intervals from 1 to 2 years. Although colonoscopy is considered a safe procedure, there are risks of severe adverse events (SAEs), such as perforation and bleeding, as well as adverse events (AEs), such as abdominal discomfort and post-colonoscopy gastrointestinal infections. Colonoscopy-related bleeding and perforation rates have been reported 0.17% and 0.11%, respectively. However, there are insufficient data regarding complications of colonoscopy-surveillance for LS patients. This study aims to investigate the risk of AEs among LS patients during colonoscopy in the Stockholm region. PATIENTS AND METHODS: This retrospective cohort study includes 351 LS patients undergoing endoscopic surveillance at the Karolinska University Hospital, August 1989 - April 2021. Data from endoscopic surveillance colonoscopies were extracted from patients' medical records. RESULTS: Of 1873 endoscopies in 351 LS patients, 12 complications (AEs) were documented within 30 days (0.64%) and with a total of 3 bleedings (SAEs, 0.16%). No perforations were identified. CONCLUSION: Colonoscopy surveillance for LS patients shows a comparatively low risk of AEs per-examination. Colonoscopy complications per-patient, including both SAEs and AEs, show a significantly higher risk. Colonoscopy complications only including SAEs, show a comparatively low risk. Understanding the lifetime risk of surveillance-related colonoscopy complications is important when designing targeted surveillance programmes.

Room for improvement: One third of Lynch syndrome patients presenting for genetic testing in a highly specialised centre in Stockholm already have cancer.

BACKGROUND: Lynch syndrome is caused by germline mutations in the mismatch repair genes and is characterised by a familial accumulation of colorectal and other cancers. Earlier identification of Lynch syndrome patients enables surveillance and might reduce the risk of cancer. It is important to explore whether today's clinical care discovers patients with Lynch syndrome suitable for surveillance in time. This study aimed to describe what led to a diagnosis of Lynch syndrome in the cohort referred to the Hereditary Gastrointestinal Cancer Unit, Karolinska University Hospital, Solna, Sweden for gastrointestinal surveillance. METHODS: This was a descriptive study. Data from 1975 to 2018 were collected and compiled as a database. Age at diagnosis was calculated from the date when a pathogenic MMR gene mutation was confirmed, from the period June 1994-September 2018. Data were collected from patient protocols prospectively during patient consultations and medical records retrospectively. Criteria for inclusion were registration at the outpatient clinic and a confirmed mismatch repair gene mutation. RESULTS: A total of 305 patients were eligible for inclusion. Three major reasons for diagnosis were identified: 1. Predictive testing of a previously known mutation in the family (62%, mean age 37), 2. A family history of Lynch associated tumours (9%, mean age 37), 3. A diagnosis of cancer (29%, mean age 51). The proportion diagnosed due to cancer has not changed over time. CONCLUSION: A high proportion of patients (29%) were identified with Lynch syndrome after they had been diagnosed with an associated cancer, which suggests that there is significant room for improvement in the diagnosis of patients with Lynch syndrome before cancer develops.