Seminars in Colon and Rectal Surgery最新文献

Rectal neuroendocrine tumors (NETs) have increased in prevalence due to increased detection via endoscopic screening for colorectal neoplasia, advances and availability of imaging tools along with the indolent nature of the tumor. Imaging techniques to identify rectal NETs include computed tomography, magnetic resonance imaging, and endoscopic rectal ultrasound. Rectal NETs are typically categorized by tumor size to determine if they should undergo endoscopic resection, local excision or transanal excision, or a radical resection, as per National Comprehensive Cancer Network guidelines. However, while examining the literature, multiple studies have examined outcomes for patients who did not adhere to these guidelines and had similar recurrence rates and survival as those patients who did. Therefore, we propose less aggressive treatment for rectal NETs in the absence of adverse features.

Local excision (LE) for early-stage rectal cancer is an attractive option compared to total mesorectal excision (TME), as it avoids many of the significant comorbidities and adverse functional outcomes associated with TME. However, LE for tumors with high-risk histopathologic features can lead to unacceptably high rates of local and distant recurrence. Neoadjuvant or adjuvant chemoradiotherapy can mitigate those risks in certain clinical settings and may expand the number of patients who can be safely treated with an organ-preserving approach. In this chapter, we will explore the available date supporting the use of neoadjuvant and adjuvant chemoradiation (CRT) for the treatment of high-risk early-stage rectal cancer and will discuss future studies that aim to answer some of the ongoing clinical questions related to this practice.

Local excision is a well-tolerated, low risk, curative oncologic operative approach for highly selected early-stage rectal cancers. As with any cancer treatment, cure is balanced with morbidity and quality of life. In this respect, the best management for a patient with an early rectal cancer highlights the clinical dilemma balancing concerns for over- versus under-treatment. That is to say, radical resection may be oncologically equivalent to local excision for true early stage cancer, yet, results in much greater morbidity, including the possibility of a permanent colostomy. Alternatively, local excision of a presumed early rectal cancer may be oncologically inferior to mesorectal excision, potentially compromising the cancer outcome dramatically. Navigating between these two surgical extremes requires incorporation of multiple critical clinico-pathologic variables, including accurate clinical staging, precise tumor localization, careful histologic assessment to recognize higher risk features, and patient fitness and preference.

While pelvic failure following local excision is generally more common than after radical resection, the gap between disease-free and overall survival is not quite as wide, particularly among lower-risk pT1Nx cancers in patients following LE. The lack of histologic lymph node staging and reliance on imperfect imaging to risk estimate micrometastatic mesorectal nodal disease, the higher morbidity associated with completion mesorectal excision pursued for a histologically higher-risk early rectal cancer, and the greater risk of an extended resection at salvage operation for locoregional recurrence collectively emphasize the degree of caution when considering a more limited excisional operative approach.

Conventional transanal excision allows a direct endoluminal approach through a natural orifice, avoiding the life altering presence of a stoma and associated morbidity and mortality of transabdominal surgery. Benign polyps and early-stage rectal cancer within the low to mid rectum can be definitively treated with transanal excision, with few complications, typically in an outpatient fashion. Other minimally invasive approaches outlined in this issue may demonstrate less specimen fragmentation, higher rate of negative margins, and decreased recurrence, but are often impractical for excising lesions in the low rectum.

Anastomotic leak is a devastating complication of gastrointestinal surgery that is associated with high morbidity and mortality. Yet, despite flawless technique in the operating room, many anastomoses still leak, suggesting that factors beyond tension and ischemia contribute to anastomotic leak. In this article, we will review the accumulating evidence that the gut microbiome plays a critical role in anastomotic healing, and then review methods of minimizing perturbances to the gut microbiome to decrease rates of anastomotic leak.

Formation of intestinal anastomosis is a commonly encountered procedure in abdominal surgery, and construction of these anastomoses should be considered an essential and basic aspect of the art of colon and rectal surgery. This chapter covers specific technical and physiological details relevant to the construction of sound intestinal anastomoses, discusses operative considerations for some specific anastomosis types commonly encountered and colon and rectal surgery, and reviews intraoperative testing and troubleshooting of anastomotic construction. Intraoperative assurance of a well perfused, tension-free, and technically secure anastomosis is the first and most essential principle for a good anastomotic outcome.

Anastomotic leak after colorectal resection is a feared complication that dramatically worsens mortality and anastomotic survival. In this chapter, we describe the evolving field of endoscopic management of anastomotic leaks. Endoscopic management of anastomotic leaks is suitable for a minority of leaks that meet the following criteria: 1) the patient is clinically well; 2) the leak is contained; 3) the leak has no drainable component, and; 4) the leak has failed clinical observation. Distinguishing a chronic abscess from a well-drained, chronic sinus is paramount to selection for safe use of endoscopic approaches. Endoscopic techniques for appropriate anastomotic leaks include marsupialization of the tract, over-the-scope endoclips, covered stents, and vacuum-assisted closure. The use of each technique can be supported when selecting for the appropriate anatomic circumstances.

Anastomotic leak is a feared complication of any bowel surgery. While the technical aspects of this complication and its management are often studied, the emotional implications on the patient and surgeon should not be overlooked. There is a growing body of literature on the management of the emotional toll complications can have on the surgeon and team. Open communication with the patient, leaning on colleagues for support, and a blame free surgical culture can be helpful for surgeons facing these dreaded outcomes. Institutional resources are scarcely utilized, but may be available as well. Patients and their families should be informed of the consequences of the complication and the potential for further sequelae to follow. By being available, truthful, and taking care of one's own response to the trauma, the surgeon can lead all involved through a difficult course.

After the initial period of source control and treating sepsis, the pervasive long-term effects of anastomotic failure become clear. Most of these produce some form of debility, require prolonged treatment with multiple procedures and operations and for some, even shorten survival. Regardless of the complication, it is imperative that the surgeon remain patient and create a treatment plan that is measured and safe. This may involve as little as a single operation for reversal of diverting stoma, the time-consuming and labor-intensive management of enterocutaneous fistulas (ECFs), serial dilations of an anastomotic stricture or managing and guiding patients through poor functional and oncologic outcomes.

Intestinal anastomotic tissue follows a similar pattern of healing that is seen in all tissues with characteristic inflammatory, proliferative, and remodeling phases. Several aspects of intestinal healing are distinct from other tissues, however, including its time course and interaction with the environment of the gastrointestinal tract. As the anastomosis progresses through each stage, initial inflammatory cells are replaced by collagen-producing fibroblasts that generate the anastomosis’ strength. A complex network of cell-to-cell signaling mediates this process through the release of cytokines and growth factors including platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), and vascular endothelial growth factor (VEGF). Interventions based on these signaling pathways have been shown to improve anastomotic strength in animals, though methods for improving anastomotic healing in human patients remain unclear. Given the risks associated with anastomotic failure in patients, there is value in monitoring inflammatory markers and cytokines that can indicate the presence of a leak.