equivalent oncological outcomes for local­ized colon cancer. The use of the laparoscopic approach should be based on the surgeon’s experience in advanced laparoscopic surgery as well as patient and tumor- specic factors. A number of large multi-institutional ran­domized trials in the United States and inter­nationally have demonstrated equivalent overall and recurrence- free survival rates

decision depends on whether the metastatic disease can be cured or not. If the metastases are potentially resectable for cure, then an aggressive surgical approach is warranted for both the primary and metastatic sites with the aim of curing the patient. Previously the number of hepatic metastases was an impor­tant criterion in determining resectability. However, in the modern era, tumor location and residual liver volume are the most useful tools. Metastatic tumors that are bilobar or that are borderline resectable due to location may be better managed with upfront chemo­therapy followed by reassessment for delayed resection. Delayed metastatic resection does not increase the risk of becoming unresect­able due to growth. However, chemotherapy negatively affects the quality of the liver parenchyma and can cause chemotherapy­associated steatohepatitis (CASH). This may require a larger future liver remnant to main­tain adequate hepatic function and reduce postoperative complications. Treatment must be individualized with a multi-disciplinary approach. Most commonly systemic chemo­therapy is administered to attempt to shrink metastatic disease so that it becomes more clearly resectable. Furthermore, progression of disease on chemotherapy may indicate aggressive biology of the tumor. Survival rates after resection of colorectal carcinoma with liver metastases are better in patients who experience an objective response to che­motherapy. Other potential treatments include combination of resection and abla­tion of metastases, staged resection (either primary or metastases rst) with chemother­apy used between resections, hepatic artery infusion pump therapy, and preoperative por­tal vein embolization to increase size of future liver remnant if residual liver volume is the main concern. One of the points of debate is whether surgical excision of the pri­mary tumor and metastasis should be carried out simultaneously or colorectal resection rst followed by hepatectomy or hepatec­tomy rst followed by resection of the pri­mary tumor. For most patients, simultaneous

resection of the primary and metastatic dis­ease is clearly preferable from the patient’s perspective, and several case series and meta­analyses have shown equivalent survival and morbidity for patients who undergo a single- stage procedure compared with delayed (staged) hepatic resection, unless major hepatic resection (three or more seg­ments) is needed. Factors that inuence the decision for single-stage surgery versus a staged approach include the anticipated com­plexity of the colectomy and hepatectomy, the size of the future liver remnant, the likelihood of major blood loss or prolonged hepatic ischemic times, and patient comor­bidities. Surgery provides a potentially cura­tive option for selected patients who present with limited metastatic colorectal cancer (CRC). If the metastases are potentially resectable, especially if they are located in one organ system (such as liver or lung), both the primary and the metastases should be managed aggressively. With the combination of surgery and chemotherapy, long-term sur­vival can be achieved in as many as 50% of cases.

resection of the primary tumor for unresect­able metastatic disease is also debated. These patients can benet from palliative surgery to relieve the symptoms of obstruction and bleeding from the primary tumor. However, many of these patients are completely asymp­tomatic or have minimal symptoms. With systemic therapy, the current median survival among patients with unresectable metastatic colon cancer is currently greater than 24months and may be as long as 34months. Previous studies had evaluated the role of primary resection in patients with stage IV disease and demonstrated an association with improved survival. However, these observa­tional studies are limited by signicant selec­tion bias and outdated chemotherapy regimens. Presently, more studies favor start­ing chemotherapy without resecting the pri­mary tumor. This approach may reduce potential delays in starting chemotherapy from surgical morbidity since the risk of

primary anastomosis can be performed in those who are good surgical candidates. Primary anastomosis is not typically per­formed in the clinical setting of diffuse peri­tonitis or free perforation, and/or in medically unstable patients. For patients with a local­ized uid collection or abscess, percutaneous drainage can be performed. However, if transabdominal drainage is performed, there is a potential for seeding of the drain tract, and therefore, at the time of denitive resec­tion, the drain tract should be resected. Similarly, perforation may cause the tumor to adhere to other organs and an en bloc resec­tion may be necessary.

ing cancer should be individualized depend­ing on the site of obstruction and the presence of proximal colonic distention with fecal load. Options for treatment may include resection with or without anastomosis (e.g., Hartmann resection), resection of the dis­tended bowel (e.g., subtotal/total colectomy), or relief of the obstruction and fecal load (e.g., endoluminal stenting or colostomy). The prognosis among patients with obstruct­ing cancers may be worse in comparison to those without obstruction because of the inherently more advanced nature of their dis­ease. However, this does not preclude the potential for curative resection. For tumors of the right or transverse colon, a tumor-directed resection removes the distended colonic seg­ment, and an enterocolonic anastomosis can generally be safely achieved due to low bac­terial counts in the right and transverse colon taking into consideration the patient’s gen­eral condition at the time of resection and the absence of other factors that indicate the need for a protective stoma. During curative resection, the principles of oncological resec­tion should be adopted. A variety of surgical options exist for patients who present with a left-sided colon obstruction from cancer. Appropriate surgical approaches include resection with end colostomy and rectal pouch (i.e., Hartmann’s procedure), resection with primary anastomosis, and subtotal col-

ectomy with ileorectal anastomosis. In a ret­rospective study of 243 consecutive patients who underwent emergent surgery for obstructing colon cancer at Queen Mary’s Hospital in Hong Kong, there was no statisti­cally signicant difference in hospital mor­tality or anastomotic leak rates among patients who underwent resection and pri­mary anastomosis regardless of tumor loca­tion (right- versus left-sided). Nevertheless, many surgeons routinely perform a tempo­rary proximal diverting colostomy following resection of an obstructing left-sided colon cancer. If a primary anastomosis is per­formed, it should be studied for integrity and patency prior to closure of the stoma. If the entire colon was not evaluated prior to the stoma formation due to the emergent situa­tion or due to an obstructing tumor, colonos­copy is indicated prior to ostomy closure. In selected patients, successful preoperative stenting may allow for colonic decompres­sion, metabolic and nutritional recovery, and adequate workup (operability, colonic evalu­ation) to optimize subsequent elective resec­tion. A randomized trial of palliative stenting versus surgery was prematurely closed owing to an unexpectedly high rate of perforations in the stented group so patients should be carefully selected. The selection of the surgi­cal approach should consider the patient’s general condition at the time of resection as well as the quality of the proximal bowel. The morbidity and mortality of a segmental resection, following intraoperative colonic irrigation, among patients with left colonic malignant obstruction has been compared with subtotal colectomy and has not been shown to be superior. Other recent studies have demonstrated that colonic irrigation may not be mandatory before primary bowel anastomosis in this setting. For patients who are not good candidates for surgery, a tempo­rizing approach for an obstructing cancer is endoscopic placement of an expandable metal stent. Endoluminal stenting in the set­ting of an obstructing colon cancer can also be used as a bridge to prepare the colon