Colon Cancer Treatment (Professional) (cont.)
IN THIS ARTICLE
Treatment Option Overview
Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)
Primary Surgical Therapy
Standard treatment for patients with colon cancer has been open surgical resection of the primary and regional lymph nodes for localized disease. The role of laparoscopic techniques [1,2,3,4] in the treatment of colon cancer has been examined in two studies. A multicenter, prospective, randomized, noninferiority trial (NCCTG-934653) compared laparoscopic-assisted colectomy (LAC) to open colectomy in 872 patients. At a median follow-up of 4.4 years, 3-year recurrence rates (16% LAC vs. 18% open colectomy; hazard ratio [HR] for recurrence = 0.86; 95% confidence interval [CI], 0.63–1.17; P = .32) and 3-year overall survival (OS) rates (86% LAC vs. 85% open colectomy; HR for death in LAC = 0.91; 95% CI, 0.68–1.21; P = .51) were similar in both groups for all stages of disease evaluated.[Level of evidence: 1iiA]. Tumor recurrence in surgical incisions was less than 1% for both groups. Decreased hospital stay (5 days LAC vs. 6 days open colectomy, P < .001) and decreased use of analgesics were reported in the LAC group. A 21% conversion rate from LAC to open procedure was shown. This study excluded patients with locally advanced disease, transverse colon and rectal tumor locations, and perforated lesions. Each of the 66 surgeons participating in the trial had performed at least 20 LACs and were accredited for study participation after independent videotape review assured appropriate oncologic and surgical principles were maintained. The quality-of-life component of this trial was published separately and minimal short-term quality-of-life benefits with LAC were reported.[Level of evidence: 1iiC] One small, single-institution randomized study of 219 patients showed that the LAC procedure was independently associated with reduced tumor recurrence on multivariate analysis.[Level of evidence: 1iiB] The role of sentinel lymph node mapping is also under clinical evaluation.[8,9]
Surgery is curative in 25% to 40% of highly selected patients who develop resectable metastases in the liver and lung. Improved surgical techniques and advances in preoperative imaging have allowed for better patient selection for resection.
The potential value of adjuvant chemotherapy for patients with stage II colon cancer is controversial. Pooled analyses and meta-analyses have suggested a 2% to 4% improvement in OS for patients treated with adjuvant fluorouracil (5-FU)–based therapy compared with observation.[10,11,12] (Refer to the section on Stage II Colon Cancer for more information.)
Prior to 2000, 5-FU was the only useful cytotoxic chemotherapy in the adjuvant setting for patients with stage III colon cancer. Since 2000, capecitabine has been established as an equivalent alternative to 5-FU and leucovorin. The addition of oxaliplatin to 5-FU and leucovorin has been shown to improve OS compared with 5-FU and leucovorin alone. (Refer to the sections on Stage III Colon Cancer and Stage IV and Recurrent Colon Cancer for more information.)
Adjuvant Radiation Therapy
While combined modality therapy with chemotherapy and radiation therapy has a significant role in the management of patients with rectal cancer (below the peritoneal reflection), the role of adjuvant radiation therapy for patients with colon cancer (above the peritoneal reflection) is not well defined. Patterns-of-care analyses and single-institution retrospective reviews suggest a role for radiation therapy in certain high-risk subsets of colon cancer patients (T4, tumor location in immobile sites, local perforation, obstruction, and residual disease postresection).[13,14,15,16,17,18] Such observations led to the development of a phase III randomized intergroup study designed to test the benefit of adding radiation therapy to surgery and chemotherapy with 5-FU-levamisole for selected high-risk colon cancer patients (T4; or T3, N1–N2 ascending and/or descending colon). This clinical trial closed early secondary to inadequate patient accrual, and analysis of 222 enrolled patients (the original goal was 700 patients) demonstrated no relapse or OS benefit for the group receiving radiation therapy, though the sample size and statistical power were inadequate to exclude benefit. Adjuvant radiation therapy has no current standard role in the management of patients with colon cancer following curative resection, though it may have a role for patients with residual disease.
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