Colorectal Cancer
Treatment Options

Colon Cancer Treatment Options

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After a colorectal cancer diagnosis, understanding your treatment options can help you and your healthcare team create a plan that fits your needs. Colorectal cancer treatment varies based on the stage and characteristics of the cancer, and each approach has unique benefits. Here’s a look at the main types of treatments—surgery, chemotherapy, radiation, and targeted therapies—so you know what to expect and can make informed choices.

Surgery: The First Line of Defense

For many patients, surgery is the most common initial treatment, especially for early-stage colorectal cancer. The goal of surgery is to remove the tumor and, when possible, any nearby lymph nodes where cancer might have spread.

Types of Surgery:

  • Polypectomy and Local Excision: If the cancer is small and detected early (often during a colonoscopy), the tumor may be removed directly through a procedure called a polypectomy or local excision. This is typically done for early-stage cancers or polyps.

  • Partial Colectomy: In this procedure, the surgeon removes the part of the colon containing the tumor, along with some surrounding healthy tissue. The remaining parts of the colon are then reconnected.

Who It’s For: Surgery is generally the first choice for early-stage cancer, and it can sometimes be curative on its own.

In Short: Surgery is often the first step, aiming to remove the cancer from the body and reduce the chance of it coming back.

Will I end up with a bag?

Most colon cancer surgery requires no ostomy at all. Tthe surgeon removes the affected section and reconnects the rest.

For rectal cancer, many people get a temporary ileostomy while the reconnection heals, usually reversed within a few months. That is not the same thing as a permanent colostomy, and the two get confused constantly. In a Swedish study following more than 4,600 rectal cancer patients, about 14% ended up with a permanent stoma. Other studies put it between 18% and 25% depending on tumour position and other factors. It is not the default outcome.

If you do end up with an ostomy: people live full, active, sexual, athletic lives with one. Ask to meet an ostomy nurse before surgery, not after.

You may not need surgery at all

For rectal cancer, treatment increasingly starts with chemotherapy and radiation before any operation, an approach called total neoadjuvant therapy. Sometimes the tumour disappears completely on scans and exams. When that happens, some patients can skip surgery entirely and go on close surveillance instead. It is called watch-and-wait.

What it is not: skipping treatment. Watch-and-wait means frequent scans and exams, sometimes for years, and if the tumour comes back, surgery is still there.

Chemotherapy: Attacking Cancer Cells

Chemotherapy uses drugs to target and destroy cancer cells throughout the body. It’s often used in combination with surgery to target any remaining cancer cells, especially if there’s a risk of spread.

  • How It’s Used: Chemotherapy can be administered before surgery (to shrink a tumor and make surgery easier) or after surgery (to kill any cancer cells left behind). It may also be used as a primary treatment if the cancer has spread beyond the colon.

  • Common Drugs: Drugs like 5-fluorouracil (5-FU), oxaliplatin, and irinotecan are commonly used in colorectal cancer treatment. They’re often given in cycles, with a period of treatment followed by a period of rest.

  • Side Effects: Chemotherapy can come with side effects like nausea, fatigue, and hair loss, but advancements in supportive care mean many side effects can be managed effectively.

In Short: Chemotherapy is a systemic treatment, meaning it works throughout the body, and is used to destroy cancer cells that may remain after surgery or to treat cancer that has spread.

Radiation Therapy: Targeted Tumor Control

Radiation therapy uses high-energy rays to target and kill cancer cells in specific areas. It’s most commonly used in rectal cancer, where it can help shrink tumors before surgery or prevent cancer from coming back after surgery.

  • How It’s Used: Radiation is typically focused on the area of the tumor and surrounding tissues. It’s often combined with chemotherapy (a combination called chemoradiation) for greater effectiveness.

  • Types of Radiation:

    • External Beam Radiation Therapy (EBRT): This is the most common type of radiation for colorectal cancer, where the radiation is directed at the tumor from outside the body.

    • Intraoperative Radiation Therapy (IORT): For certain rectal cancers, radiation may be applied directly to the area during surgery.

Who It’s For: Radiation therapy is commonly used for rectal cancer, but it’s generally less common for colon cancer unless there’s a specific need.

In Short: Radiation therapy is a local treatment focused on shrinking tumors or killing cancer cells in specific areas, often in combination with other treatments.

Targeted Therapy: Precision Treatment Based on Cancer’s Profile

Targeted therapy uses drugs that specifically attack cancer cells based on certain characteristics, like specific proteins or genetic mutations. Biomarker testing helps determine if targeted therapy is an option by identifying unique features of the cancer.

  • How It Works: Unlike chemotherapy, which targets all fast-growing cells, targeted therapies work on particular proteins or pathways involved in cancer growth. This precision approach often means fewer side effects than traditional chemotherapy.

  • Common Targeted Therapies for Colorectal Cancer:

    • EGFR Inhibitors: Drugs like cetuximab (Erbitux) and panitumumab (Vectibix) block the EGFR protein, which can help slow or stop cancer growth in tumors that don’t have KRAS or NRAS mutations.

    • VEGF Inhibitors: Drugs like bevacizumab (Avastin) and ramucirumab (Cyramza) target VEGF, a protein that promotes blood vessel growth in tumors. By inhibiting VEGF, these drugs help starve the tumor of nutrients needed to grow.

Who It’s For: Targeted therapies are typically used for advanced or metastatic colorectal cancer. Your doctor will recommend targeted therapy if your biomarker testing shows your cancer has the right traits.

In Short: Targeted therapy is a precision treatment that goes after specific features of cancer cells, making it an option for patients with advanced cancer who have certain biomarkers.

Immunotherapy

If your biomarker testing came back MSI-H or dMMR, meaning your tumor has a lot of genetic ‘mistakes,’ your cancer may respond to immunotherapy, which works by helping your own immune system recognize the cancer. About 15% of colon cancers are dMMR.

For advanced disease, immunotherapy is already a standard option for these tumors.

For earlier-stage disease, the results have been striking and the approvals have not caught up yet. In a study published in 2025, every one of 49 patients with dMMR rectal cancer treated with the immunotherapy drug dostarlimab had their tumor disappear completely, with no surgery. That drug is currently under FDA review for this use, with a decision expected in early 2027. It is not approved for rectal cancer yet. Separately, a large 2025 trial found that adding immunotherapy to chemotherapy after surgery improved outcomes in stage III dMMR colon cancer.

What to do with that: make sure your tumor has been tested for MMR and MSI status. It should be standard for every colorectal cancer. If it comes back dMMR, ask specifically about immunotherapy and about clinical trials. This is a fast-moving area and the standard of care is genuinely changing.

Which Treatment is Right for You?

The right combination of treatments depends on many factors, including your cancer’s stage, your overall health, and your preferences. Here’s a quick guide to how treatments are typically used at each stage:

  • Early Stages (Stage 0 and I): Surgery alone is often enough to remove the cancer.

  • Intermediate Stages (Stage II and III): Surgery combined with chemotherapy, and sometimes radiation for rectal cancer, is common.

  • Advanced Stages (Stage IV): A combination of surgery, chemotherapy, and targeted therapy may be used to manage the cancer and improve quality of life.

Your healthcare team will discuss the best options based on your specific situation, helping you understand the role each treatment can play in your recovery journey.