Colorectal Cancer _ ___________________________________________________________________________
5-FU, and oxaliplatin (FOLFOX) is considered reasonable in high-risk cases, but it is not indicated in good-to-average-risk stage II cancers. Stage III Stage III colon cancer denotes lymph node involvement. Studies have shown that prognosis is related to the number of involved lymph nodes; patients with one to three involved nodes have a significantly better survival than those with four or more involved nodes. Before 2000, 5-FU was the only adjuvant chemotherapy with activity in stage III colon cancer. With patients in many earlier trials of adjuvant 5-FU not showing a survival benefit, modifications and additions to the core 5-FU therapy were investigated in stage III colon cancer. More recently, capecitabine was established as comparable to 5-FU/leucovorin. The addition of oxaliplatin to 5-FU/ leucovorin (FLOX) improved overall survival compared with 5-FU/leucovorin alone and has become the reference standard for the future generation of clinical trials for stage III colon cancer [201; 220; 241]. For stage II/III colon cancer, the NCCN asserts that adjuvant bevacizumab, cetuximab, panitumumab, or irinotecan should not be used outside of clinical trials [220]. In stage III colon cancer, FOLFOX is superior to 5-FU/leucovorin, and capecitabine/oxaliplatin (CAPEOX) is superior to bolus 5-FU/ leucovorin. FLOX is an alternative to FOLFOX or CAPEOX, but FOLFOX or CAPEOX are preferred [220]. Adjuvant Radiation Therapy Unlike in rectal cancer, the role of adjuvant radiation therapy is poorly defined in colon cancer treatment. Radiation therapy has no current adjuvant role following curative resection but may have a potential role in patients with residual disease [220]. If used, radiation fields should include the tumor bed, as defined by preoperative radioimaging or surgical clips. Radiation should be given in doses of 45–50 Gy in 25 to 28 fractions; the dose in the small bowel should be no greater than 45 Gy [220]. Neoadjuvant chemoradiotherapy that includes 5-FU should be delivered concurrently to aid resectability. Conformal external beam radiation is preferred; intensity- modulated radiation therapy should be limited to unique clinical situations. Intraoperative radiation therapy should be considered in T4 or recurrent cancer [220]. TREATMENT OF RECTAL CANCER, STAGES 0–III The standard treatment options for rectal cancer are [205]: • Stage 0: Polypectomy or surgery • Stage I: Surgery with or without chemoradiation therapy • Stage II and III: Surgery, neoadjuvant
For resectable non-metastatic colon cancer, the National Comprehensive Cancer Network preferred surgical procedure is colectomy with en bloc removal of the regional lymph nodes. (https://www.nccn.org/professionals/ physician_gls/pdf/colon.pdf. Last accessed March 14, 2022.) Level of Evidence : 2a (Based upon lower-level evidence, there is uniform NCCN consensus that the intervention is appropriate.) Surgery is curative in 25% to 40% of highly selected patients who develop resectable metastases in the liver and lung. Refinements in surgical technique and preoperative imaging have improved patient selection and resection outcomes [201; 232; 233; 234]. Before surgery, all patients should be given information about the likelihood of having a stoma, why it might be necessary, and how long it might be needed. The psychologic and emotional impacts of having a stoma should not be overlooked. Between 16% and 26% of patients with a stoma will experience negative psychologic symptoms immediately postoperatively, including anxiety, depression, and suicidal ideation [235; 236]. Having a stoma also can potentially decrease patients’ quality of life as they experience changes to body image, sexual function, social isolation, stigma, embarrassment, and decreased mood [237]. A trained stoma professional should provide specific information on the care and management of stomas to all patients considering surgery that might result in a stoma [238]. Post-Resection Staging Given that tumor depth, nodal metastasis, and distant metastasis strongly predict post-surgical prognosis in colon cancer, staging should be performed following surgical resection using TNM staging, histologic grade of the tumor, and resection completeness [188].
Adjuvant Chemotherapy Stage II
The value of adjuvant chemotherapy for stage II colon cancer is controversial. In one study, adjuvant 5-FU-based chemotherapy was evaluated in patients with high-risk stage II colon cancer following curative resection. Compared with surgery alone, adjuvant 5-FU showed inconsistent benefit; these and other results led to guidelines issued by the American Society of Clinical Oncology (ASCO) stating that evidence does not support the routine use of adjuvant chemotherapy for patients with stage II colon cancer [239; 240]. The NCCN guideline also states there is no survival advantage by adding oxaliplatin to 5-FU/leucovorin, including in patients 70 years of age or older [220]. The combination of folic acid,
chemoradiotherapy, short-course neoadjuvant radiotherapy, and adjuvant chemoradiotherapy
• Stage IV, metastatic, and recurrent: Surgery with or without chemotherapy or radiotherapy, chemotherapy, and targeted therapy
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