Patients with Stage 0 or Stage I CRC have cancer that is limited to a polyp, found within the colon during colonoscopy, or cancer that has spread into the colon wall, but not through it. These patients can often be cured with surgical removal of the tumor, either with polypectomy performed with a colonoscope, or with a partial colectomy. In this case, the goal of therapy is a cure. No chemotherapy, targeted agent, or radiation therapy is normally recommended.

Patients with Stage II disease have cancer that has spread beyond the colon wall but has not invaded local lymph nodes, while those with Stage III disease also have lymph node involvement. The goal of therapy in these patients is also a cure. Surgery is recommended in most patients with Stage II and III disease. However, patients with high-risk Stage II colon cancer may require adjuvant chemotherapy, and those with Stage II rectal cancer require chemotherapy given in tandem with radiation therapy. Chemotherapy is usually recommended for all patients with Stage III colon cancer, and chemotherapy with concomitant radiation therapy is recommended for patients with Stage III rectal cancer.