Microsatellite instability is highly prevalent in older patients with colorectal cancer

BackgroundClinical guidelines suggest screening of colorectal cancer (CRC) for microsatellite instability (MSI). However, microsatellite instability—high (MSI-H) CRC is not rare in older patients. This study aimed to investigate the prevalence of MSI-H CRC in an unselected population in an age-based manner.Material and methodsA retrospective analysis of data from patients undergoing radical surgery for CRC was performed. Only cases with results from MSI testing using immunochemistry (IHC) were analyzed. Age-based analyses were performed using two cut-off ages: 50 years. as stated in Amsterdam II guidelines, and 60 years. as outlined in the revised Bethesda criteria.ResultsThe study population included 343 (146 female and 197 male) patients with a median age of 70 years (range 21–90 years). The prevalence of MSI-H tumors in the entire cohort was 18.7%. The prevalence of MSI-H CRC was 22.5% in the group ≤50 years vs. 18.2% in the group >50 years using the age limit in the Amsterdam II guidelines. MSI-H CRC was present in 12.6% of the group aged ≤60 years compared to 20.6% in the control group >60 years.ConclusionMSI screening of CRC based on age alone is associated with negative selection of a relevant number of cases. MSI-H CRC is also common in elderly patients, who may be negatively selected secondary to an age-based screening algorithm. Following the results of this study, screening based on clinical criteria should be omitted in favor of systematic screening as is already internationally practiced

The safety of surgical technique for ileostomy and colostomy in preventing parastomal hernias: an in vitro experimental simulation study

Background!#!Parastomal hernia (PH) is a common long-term complication in persons with an ostomy. Although the cause of PH may be multifactorial, the surgical technique employed for the creation of a stoma may be a risk factor for the development of PH. The traditional technique of cruciate fascia incision may predispose to increased pressure zones at the ostomy exit site, thereby increasing the risk of PH. A circular excision of the abdominal fascia at the ostomy exit site enables a uniform pressure distribution, thereby reducing the risk of PH. This hypothesis was tested in this in vitro experimental simulation study.!##!Methods!#!The effect of the surgical technique for ostomy creation on the risk of PH development was investigated in this in vitro experimental simulation study. The pressure development at the stoma site was compared for the traditional cruciate incision vs. circular fascia excision.!##!Results!#!The pressure at the ostomy site was about four-times higher in the tradition cruciate incision technique compared to the circular excision technique. This finding was independent of unilateral (e.g. peritoneal) pressure application.!##!Conclusion!#!The main finding from this study suggests that the traditional cruciate incision of the abdominal fascia for the creation of an intestinal ostomy predisposes to increased pressures at the ostomy site, thus increasing the risk of PH. This effect is not seen in the experimental setting following a circular excision of the fascia. Thus, this surgical aspect may be adopted as a possible means of reducing the risk of parastomal hernia in patients undergoing ostomy surgery