Colonic stent for bridge to surgery for acute left-sided malignant colonic obstruction: A review of the literature after 2020.

It has been found that 8%-29% of colorectal cancers are obstructive. The use of "stent as bridge to surgery" is one of the most debated topics in obstructive left-sided colorectal cancer management. The endoscopic placement of a self-expanding metallic stent as bridge to surgery (BTS) could turn an emergency surgery to an elective one, increasing the number of primary anastomoses instead of stoma and facilitating the laparoscopic approach instead of an open one. However, in recent years the possible risk of perforations and microperforations facilitating cancer spread related to the use of self-expanding metallic stent for BTS has been highlighted. Therefore, despite the useful short-term outcomes related to BTS, the recent literature has focused on long-term outcomes investigating the disease-free survival, the recurrence rate and the overall survival. Due to discordant data, international guidelines are still conflicting, and the debate is still open. There is not agreement about using self-expanding metallic stent for BTS as the gold standard.

Proteogenomic biomarkers in colorectal cancers: clinical applications.

INTRODUCTION: Colorectal cancer (CRC) is one of the leading cancers in terms of incidence and mortality, rate requiring a multidisciplinary approach. The discovery of specific CRC biomarkers has caused a paradigm shift in its clinical management. AREAS COVERED: The aim is to illustrate the possible clinical applications of CRC biomarkers through an updated literature review (from 2015 to 2020) based on the PubMed database. A relationship between cancer localization and genetic profile has been identified. Nowadays, the tumor markers are largely used to select patients that could really benefit from a specific type of adjuvant therapy, in order to optimize treatment programs, especially in metastatic patients. This review highlights both CRC biomarkers' advantages and critical issues. EXPERT OPINION: New biomarker discoveries allow to set noninvasive tests that could increase patient's compliance with therapy. They also permit a cost-effective early diagnosis, as well as patient-tailored treatments, improving the overall survival. The CRC biomarkers could also have a prognostic value, and usually, they are included in follow-up programs. However, despite the continuous progression of new technologies, their clinical validation is still debated. In this context, additional clinical studies are still necessary to identify, among potential markers, the most effective ones.

Obstructing Left-Sided Colonic Cancer: Is Endoscopic Stenting a Bridge to Surgery or a Bridge to Nowhere?

For the 8-29% colorectal cancers that initially manifest with obstruction, emergency surgery (ES) was traditionally considered the only available therapy, despite high morbidity and mortality rates and the need for colostomy creation. More recently, malignant obstruction of the left colon can be temporized by endoscopic placement of a self-expanding metallic stent (SEMS), used as bridge to surgery (BTS), facilitating a laparoscopic approach and increasing the likelihood that a primary anastomosis instead of stoma would be used. Despite these attractive outcomes, the superiority of the BTS approach is not clearly established. Few authors have stressed the potential cancer risk associated with perforations that may occur during endoscopic stent placement, facilitating neoplastic spread and negatively impacting prognosis. For this reason, the current literature focuses on long-term oncologic outcomes such as disease-free survival, overall survival and recurrence rate that do seem not to differ between the ES and BTS approaches. This lack of consensus has spawned differing and sometimes discordant guidelines worldwide. In conclusion, 20 years after the first description of a colonic stent as BTS, the debate is still open, but the growing number of articles about the use of SEMS as a BTS signifies a great interest in the topic. We hope that these data will finally converge on a single set of recommendations supporting a management strategy with well-demonstrated superiority.