gastrointestinal disorders
Colorectal Cancer
Treatment of Colorectal Cancer
Surgical resection, sometimes combined with chemotherapy, radiation, or both Surgical resection is the mainstay for curative-intent treatment of CRC. Resection consists of removal of the anatomic segment of the large intestine harboring the tumor along with its regional lymphatic drainage. In general, a wide, 5-cm margin is planned, but a negative margin of any distance is acceptable. Resection is typically followed by reconnection of the bowel segments to restore enteral continuity (anastomosis). sphincter-sparing surgical resection (low anterior resection) can be done in patients with low tumors near, but not involving, the anal sphincter complex without significant risk of local recurrence or decreased long-term survival. Sphincter-sparing procedures necessitate a low anastomosis, which often is followed by functional issues postoperatively (eg, fecal leakage, incontinence). If there is local recurrence or poorly tolerated bowel function after a sphincter-sparing procedure, an abdominoperineal resection (APR) with permanent colostomy is usually recommended ( Treatment references ). Metastatic Liver Cancer , Number of metastatic lesions in the liver Amount of liver parenchyma involved with metastatic disease Resectability of the involved segments of the liver Synchronous vs metachronous presentation Tumor biology (presence ofKRAS,NRAS, orBRAFmutations) Patients with liver metastases should be evaluated for treatment options by a multidisciplinary team that includes medical oncologists, radiation oncologists, interventional radiologists, and hepatobiliary surgeons. A multidisciplinary team is critical to the treatment decision-making process. Incolon cancer,postoperative chemotherapy is indicated for patients with stage III disease (lymph node-positive) or patients with high-risk stage II disease (lymph node-negative but high-risk features seen on pathology such as lymphovascular invasion) (see table). decisions regarding adjuvant therapy have become increasingly complicated in the past 5 years because of several recent studies that have introduced the idea of using total neoadjuvant therapy (delivery of all chemotherapy and radiation before surgery) ( Treatment references , In general, patients who are stage T3 or T4 or who are suspected of having nodal disease will receive both chemotherapy and chemoradiation in conjunction with surgical resection. After curative surgical resection of colorectal cancer, surveillance colonoscopy should be done 1 year after surgery or after the clearing preoperative colonoscopy ( Treatment references ). A second surveillance colonoscopy should be done 3 years after the 1-year surveillance colonoscopy if no polyps or tumors are found. Thereafter, surveillance colonoscopy should be done every 5 years. If the preoperative colonoscopy was incomplete because of an obstructing cancer, a completion colonoscopy should be done 3 to 6 months after surgery to detect any synchronous cancers and to detect and resect any precancerous polyps ( Additional screening for recurrence should include history, physical examination, and serum carcinoembryonic antigen levels every 3 months for 3 years and then every 6 months for 2 years. Imaging studies (CT or MRI) are done every 6 to 12 months for 5 years. When curative surgery is not possible or the patient is an unacceptable surgical risk, limited palliative surgery (eg, to relieve obstruction or resect a perforated area) may be indicated; median survival is 7 months. Some obstructing tumors can be debulked by electrocoagulation or held open by stents. Chemotherapy may shrink tumors and prolong life for several months. Chemotherapy drugs, used singly or in combinations, includecapecitabine(a 5-fluorouracilprecursor),irinotecan, andoxaliplatin. Monoclonal antibodies such asbevacizumab,cetuximab, andpanitumumabare also used selectively with some effectiveness. No regimen is clearly more effective for prolonging life in patients with metastatic CRC, although some regimens delay disease progression. Chemotherapy for advanced colon cancer should be managed by an experienced medical oncologist who has access to investigational medications or clinical trials. When metastases are confined to the liver but cannot be surgically resected, hepatic artery infusion withfloxuridineor radioactive microspheres, given either intermittently in a radiology department or given continuously via an implantable subcutaneous pump or an external pump worn on the belt, may offer more benefit than systemic chemotherapy; however, these therapies are of uncertain benefit, and clinical trials are underway to understand their relative benefits and harms. Stereotactic radiation therapy or thermal ablation using radiofrequency or microwave treatments also can be considered for palliation. 1.Bujko K, Rutkowski A, Chang GJ, et al: Is the 1-cm rule of distal bowel resection margin in rectal cancer based on clinical evidence? A systematic review.Ann Surg Oncol19(3):801–808, 2012. doi: 10.1245/s10434-011-2035-2 2.Garcia-Aguilar J, Patil S, Gollub MJ, et al: Organ preservation in patients with rectal adenocarcinoma treated with total neoadjuvant therapy.J Clin Oncol40(23):2546–2556, 2022. doi: 10.1200/JCO.22.00032 3.Bahadoer RR, Dijkstra EA, van Etten B, et al: Short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME) versus preoperative chemoradiotherapy, TME, and optional adjuvant chemotherapy in locally advanced rectal cancer (RAPIDO): A randomised, open-label, phase 3 trial.Lancet Oncol22(1):29–42, 2021. doi: 10.1016/S1470-2045(20)30555-6.Clarification and additional information.Lancet Oncol22(2):e42, 2021. 4.Conroy T, Bosset JF, Etienne PL, et al: Neoadjuvant chemotherapy with FOLFIRINOX and preoperative chemoradiotherapy for patients with locally advanced rectal cancer (UNICANCER-PRODIGE 23): A multicentre, randomised, open-label, phase 3 trial.Lancet Oncol22(5):702–715, 2021. doi: 10.1016/S1470-2045(21)00079-6 5.Kahi CJ, Boland R, Dominitz JA, et al: Colonoscopy surveillance after colorectal cancer resection: Recommendations of the US multi-society task force on colorectal cancer.Gastroenterology150:758–768, 2016. doi: 10.1053/j.gastro.2016.01.001 