Macdonald J S
Temple University Cancer Center in Philadelphia, Pennsylvania, USA.
CA Cancer J Clin. 1997 Jul-Aug;47(4):243-56. doi: 10.3322/canjclin.47.4.243.
Adjuvant therapy for colon cancer is now a mature and widely accepted standard of care for patients with resected large bowel tumors: adjuvant therapy for stage III colon cancer has also been shown to be highly cost-effective. The cost of 5-FU/levamisole therapy for stage III colon cancer per year of life saved is less than $ 5,000, which represents a favorable cost-benefit relationship for a medical intervention. The clinician managing a patient with colon cancer at the present time has several options for therapy. In patients with stage III colon cancer, therapy with 5-FU-based regimens clearly increases overall and disease-free survival. It is also clear that the results that have been obtained are not perfect; therefore, the first option of therapy should always be an ongoing clinical trial. Many such trials are available, and Table 7 lists currently active studies in the United States. The clinician managing a patient with stage III colon cancer who is not in a clinical trial may choose a variety of regimens administered for durations of 6 to 12 months (Table 8). The preponderance of evidence suggests that 5-FU plus levamisole for 12 months is equal in efficacy to 5-FU plus leucovorin-based regimens given for a shorter period of time. A clinician may still choose the 5-FU plus levamisole regimen because of the decreased oral, myelosuppressive, and diarrheal toxicities associated with that regimen as opposed to the 5-FU/leucovorin regimens. Portal vein infusion of fluorinated pyrimidines still must be considered investigational. Finally, although we cannot be absolutely sure about the benefit of adjuvant therapy in patients with resected node-negative colon cancer, the NSABP data suggest that some benefit may be seen in these patients. It is known that patients with stage II cancers demonstrating high-grade bowel obstruction or bowel perforation have poor prognoses with surgery alone. Such patients may be good candidates for adjuvant therapy. Also, a major effort to define high risk and low risk for recurrence in patients with stage II colon cancer by analyzing molecular genetic factors (tumor ploidy and alternations in tumor suppressor genes) may lead to a selection of Dukes B patients definitely requiring adjuvant therapy.
III期结肠癌的辅助治疗也已证明具有很高的成本效益。III期结肠癌采用5-氟尿嘧啶/左旋咪唑疗法，每挽救一年生命的成本低于5000美元，这对于一种医学干预措施来说代表了良好的成本效益关系。目前，负责治疗结肠癌患者的临床医生有多种治疗选择。对于III期结肠癌患者，基于5-氟尿嘧啶的治疗方案明显提高了总生存率和无病生存率。同样明显的是，所取得的结果并不完美；因此，治疗的首选始终应该是正在进行的临床试验。有许多这样的试验可供选择，表7列出了美国目前正在进行的研究。负责治疗未参加临床试验的III期结肠癌患者的临床医生可以选择多种疗程为6至12个月的治疗方案（表8）。大量证据表明，5-氟尿嘧啶加左旋咪唑治疗12个月的疗效与短期内给予的基于5-氟尿嘧啶加亚叶酸的治疗方案相当。临床医生可能仍会选择5-氟尿嘧啶加左旋咪唑方案，因为与5-氟尿嘧啶/亚叶酸方案相比，该方案的口服、骨髓抑制和腹泻毒性较低。门静脉输注氟嘧啶仍被视为研究性治疗。最后，尽管我们不能绝对确定辅助治疗对已切除淋巴结阴性结肠癌患者的益处，但NSABP的数据表明这些患者可能会有一些益处。已知表现出高度肠梗阻或肠穿孔的II期癌症患者仅接受手术预后较差。这类患者可能是辅助治疗的合适人选。此外，通过分析分子遗传因素（肿瘤倍体和肿瘤抑制基因的改变）来确定II期结肠癌患者复发的高风险和低风险的一项主要工作，可能会导致选择出明确需要辅助治疗的Dukes B期患者。
