Table 7. Treatment Options for Stage IV and Recurrent Colon Cancer continued...
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.[8,9,10] (Refer to the Stage II Colon Cancer Treatment section of this summary 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 Stage III Colon Cancer Treatment section of this summary 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 (e.g., T4, tumor location in immobile sites, local perforation, obstruction, and residual disease postresection).[11,12,13,14,15,16]
Evidence (adjuvant radiation therapy):
- 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 (e.g., 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.