Colorectal Cancer Treatment by Stage

After a colorectal cancer diagnosis, your RMCC GI cancer specialist will recommend a treatment plan. Several factors influence the treatments chosen, including the stage of colon or rectal cancer. The cancer’s stage helps the oncologist understand the extent of the cancer’s growth.

Our multidisciplinary team uses the stage of colon or rectal cancer along with other factors, including biomarkers, to develop a tailored plan that meets each patient’s specific needs.

Stage 0 Carcinoma in Situ

This is the earliest stage of colorectal cancer, where the cancer has not spread beyond the inner lining of the colon or rectum. At this stage, surgery to remove the polyp or area affected by cancer is typically enough. Surgical procedures may include polypectomy during colonoscopy, local excision, or transanal resection for rectal cancers. If the tumor is too large for local excision, a more extensive surgery, such as a partial colectomy, may be necessary to remove part of the colon and nearby lymph nodes.

Stage I Colorectal Cancer Treatment

In Stage I, the cancer has grown into the inner layers of the colon or rectal wall but has not spread outside the colon or rectum, or to nearby lymph nodes. If a polyp is found, it's removed during a colonoscopy, and no further surgery is typically needed if the margins are clear of cancer cells. Additional surgery may be necessary for high-grade polyps, polyps that cannot be entirely removed, or if cancer cells are present in the margins.

Cancers that are not associated with a polyp are generally treated with partial colectomy. The lymph nodes may be evaluated to ensure they are free of cancer cells. If cancer is found, chemotherapy may be recommended. 

Stage II Colorectal Cancer Treatment

Stage II colorectal cancers have grown through the wall of the colon or rectum and may have invaded nearby tissues, but have not spread to the lymph nodes. Surgery is the primary treatment option for stage II colorectal cancer, and often involves a partial colectomy along with the removal of nearby lymph nodes.

Some patients may require neoadjuvant therapy (treatment before surgery) if the tumor has invaded or is attached to surrounding organs. The right treatment is based on the results of testing for MSI-H and dMMR biomarkers. If present, immunotherapy may be a better treatment option than chemotherapy.

For patients who did not receive chemotherapy before surgery, or if surgery was not possible, chemotherapy can be used if the tumor does NOT have dMMR or MSI-H. This is especially helpful for patients whose cancer has a high risk of recurring. 

Stage III Colorectal Cancer Treatment

Stage III colorectal cancer has spread to nearby lymph nodes but has not metastasized to other parts of the body. The standard treatment at this stage typically involves surgery to remove the cancerous portion of the colon along with any affected lymph nodes. Chemotherapy after surgery, which may include regimens such as FOLFOX or CAPEOX, is also a common approach. 

Biomarker testing may be conducted to identify specific genetic mutations or protein overgrowth in the tumor. The results of this molecular profiling will guide oncologists in determining whether targeted therapy or immunotherapy could be effective.

In cases where the cancer cannot be surgically removed, chemotherapy or immunotherapy can be administered to shrink the tumor so that surgery can be performed. For patients with rectal cancer, radiation therapy may also be considered.

Stage IV Metastatic Colorectal Cancer Treatment

Stage IV colorectal cancer has spread from the colon to the lymph nodes and distant organs, such as the liver, lungs, brain, peritoneum, or lymph nodes.

If the cancer can't be treated surgically to remove all of it, the primary treatment is systemic chemotherapy and/or targeted therapy. However, surgery or ablation may be necessary in select cases where the cancer is blocking, or could block, the colon. 

Common chemotherapy and targeted therapy regimens include FOLFOX, FOLFIRI, CAPEOX, and FOLFOXIRI, as well as targeted agents such as bevacizumab or cetuximab. The choice of targeted treatments will depend on the presence of certain genetic mutations, including KRAS, NRAS, and BRAF.

Additional treatments may involve immunotherapies for MSI-H or dMMR tumors, as well as radiation therapy used for palliative care to manage symptoms and enhance the patient's quality of life. Participation in clinical trials may also be considered.

Recurrent Colorectal Cancer

Recurrent colorectal cancer refers to cancer that has returned after the initial treatment. The approach to treating recurrence depends on whether it has returned locally or at a distant site, as well as which treatments were previously used. Treatment options for recurrence may include surgery, chemotherapy, radiation, or participation in clinical trials.

Why Choose RMCC for Colorectal Cancer Care

At Rocky Mountain Cancer Centers, we understand that every patient’s needs are unique. Our GI oncologists use a team-based approach to develop personalized treatment plans using the latest advancements in colon and rectal cancer therapies, biomarker testing, and clinical research trials when appropriate.

If you or a loved one was diagnosed with colorectal cancer, request an appointment at any of our locations in Aurora, Boulder, Centennial, Colorado Springs, Denver, Englewood, Lakewood, Littleton, Lone Tree, Longmont, Steamboat Springs, or Thornton, Colorado.