Colectomy and desmoid tumours in familial adenomatous polyposis: a systematic review and meta-analysis

Desmoid tumours (DT) are one of the main causes of death in patients with familial adenomatous polyposis (FAP). Surgical trauma is a risk factor for DT, yet a colectomy is inevitable in FAP to prevent colorectal cancer. This systematic review and meta-analysis aimed to synthesize the available evidence on DT risk related to type, approach and timing of colectomy. A search was performed in MEDLINE, EMBASE and the Cochrane Library. Studies were considered eligible when DT incidence was reported after different types, approaches and timing of colectomy. Twenty studies including 6452 FAP patients were selected, all observational. No significant difference in DT incidence was observed after IRA versus IPAA (OR 0.99, 95% CI 0.69–1.42) and after open versus laparoscopic colectomy (OR 0.88, 95% CI 0.42–1.86). Conflicting DT incidences were seen after early versus late colectomy and when analysing open versus laparoscopic colectomy according to colectomy type. Three studies reported a (non-significantly) higher DT incidence after laparoscopic IPAA compared to laparoscopic IRA, with OR varying between 1.77 and 4.09. A significantly higher DT incidence was observed in patients with a history of abdominal surgery (OR 3.40, 95% CI 1.64–7.03, p = 0.001). Current literature does not allow to state firmly whether type, approach, or timing of colectomy affects DT risk in FAP patients. Fewer DT were observed after laparoscopic IRA compared to laparoscopic IPAA, suggesting laparoscopic IRA as the preferred choice if appropriate considering rectal polyp burden. PROSPERO registration number CRD42020161424.

BRCA1 Norway: comparison of classification for BRCA1 germline variants detected in families with suspected hereditary breast and ovarian cancer between different laboratories

Pathogenic germline variants in Breast cancer susceptibility gene 1 (BRCA1) predispose carriers to hereditary breast and ovarian cancer (HBOC). Through genetic testing of patients with suspected HBOC an increasing number of novel BRCA1 variants are discovered. This creates a growing need to determine the clinical significance of these variants through correct classification (class 1–5) according to established guidelines. Here we present a joint collection of all BRCA1 variants of class 2–5 detected in the four diagnostic genetic laboratories in Norway. The overall objective of the study was to generate an overview of all BRCA1 variants in Norway and unveil potential discrepancies in variant interpretation between the hospitals, serving as a quality control at the national level. For a subset of variants, we also assessed the change in classification over a ten-year period with increasing information available. In total, 463 unique BRCA1 variants were detected. Of the 126 variants found in more than one hospital, 70% were interpreted identically, while 30% were not. The differences in interpretation were mainly by one class (class 2/3 or 4/5), except for one larger discrepancy (class 3/5) which could affect the clinical management of patients. After a series of digital meetings between the participating laboratories to disclose the cause of disagreement for all conflicting variants, the discrepancy rate was reduced to 10%. This illustrates that variant interpretation needs to be updated regularly, and that data sharing and improved national inter-laboratory collaboration greatly improves the variant classification and hence increases the accuracy of cancer risk assessment.

Positive experiences of healthcare professionals with a mainstreaming approach of germline genetic testing for women with ovarian cancer

According to current guidelines, all women with epithelial ovarian cancer are eligible for genetic testing for BRCA germline pathogenic variants. Unfortunately, not all affected women are tested. We evaluated the acceptability and feasibility for non-genetic healthcare professionals to incorporate germline genetic testing into their daily practice. We developed and implemented a mainstreaming pathway, including a training module, in collaboration with various healthcare professionals and patient organizations. Healthcare professionals from 4 different hospitals were invited to participate. After completing the training module, gynecologic oncologists, gynecologists with a subspecialty training in oncology, and nurse specialists discussed and ordered genetic testing themselves. They received a questionnaire before completing the training module and 6 months after working according to the new pathway. We assessed healthcare professionals’ attitudes, perceived knowledge, and self-efficacy, along with the feasibility of this new mainstream workflow in clinical practice, and evaluated the use and content of the training module. The participation rate for completing the training module was 90% (N = 19/21). At baseline and after 6 months, healthcare professionals had a positive attitude, high perceived knowledge and high self-efficacy toward discussing and ordering genetic testing. Knowledge had increased significantly after 6 months. The training module was rated with an average of 8.1 out of 10 and was considered useful. The majority of healthcare professionals (9/15) was able to discuss a genetic test in five to 10 min. After completion of a training module, non-genetic healthcare professionals feel motivated and competent to discuss and order genetic testing themselves.