Rectal Cancer Treatment Options By Stage

Treatment of your rectal cancer will depend on a number of factors. The most important factor in determining which treatment option is best for you is the stage of your rectal cancer, as early-stage rectal cancer responds to different treatments compared to the later stages

Where the cancer is located in your body and your specific cancer biomarkers also play a role in determining which treatment is most appropriate for you.

Although rectal cancers are often classified under the umbrella term colorectal cancer, which includes colon cancer, there are significant differences between rectal cancer and colon cancer and their treatment. This is because of the anatomy of the rectum and its close proximity to other important structures within the body.

Have you considered clinical trials for Rectal cancer?

We make it easy for you to participate in a clinical trial for Rectal cancer, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

Treatment of rectal cancer by stage

Once your doctor has diagnosed your rectal cancer stage, they will discuss the available treatment options with you. Various specialists may be involved in your treatment plan, including a colorectal surgeon and oncologist.

Stage 0

Stage 0 rectal cancer means it has not spread beyond the lining of the rectal wall. This allows it to be completely removed with minimally invasive surgery, such as polypectomy or local excision. This type of treatment is usually curative and won’t require any radiation therapy or chemotherapy, so an oncologist is unlikely to be involved in your treatment plan.

After treatment, you will require follow-up screening, as having had rectal cancer puts you at risk for developing colorectal cancer again in the future.

Stage I

If you have been diagnosed with stage I rectal cancer, it means that cancer has spread into the wall of the rectum but hasn’t yet spread beyond it. You will likely undergo surgery as your main treatment option.

In many cases, it is possible for surgery to completely remove cancer. However, there will be some cases where cancer cells are left behind after surgery. 

In these cases, you may need extra radiation therapy or chemotherapy after surgery to remove the remaining cells. The most commonly used chemotherapy drugs are 5-FU¹ and capecitabine².

Stage II

If you are diagnosed with stage II rectal cancer, it means that cancer has spread through the rectal wall and into the adjacent tissue. You will most likely require chemoradiation (a combination of radiation therapy and chemotherapy) before surgery. 

You may also receive chemotherapy for about four months after surgery, although this varies between treatment centers. Some centers may offer chemotherapy and chemoradiation upfront to all stage II and III patients. 

Stage III

A diagnosis of stage III rectal cancer means that your cancer has spread through the rectal wall into the adjacent tissue as well as to nearby lymph nodes. Effective treatment will most likely require chemoradiation prior to surgery. Chemoradiation usually shrinks the tumor, making it easier to remove, and also decreases the chance of cancer recurring in the same area after surgery.

You may require post-operative chemotherapy after surgery to ensure that any cancer cells that may have spread are eliminated.

Stage IV

If you are diagnosed with stage IV rectal cancer, it means that cancer has spread from its original site in the rectum to other organs, such as the liver or the lungs. Treatment will vary according to which organs cancer has spread to and how big the metastatic tumors are.

If there is a possibility that cancer can be completely removed both in the rectal area and in another affected organ, your treatment will involve a combination of surgery, radiation therapy, and chemotherapy. Your surgeon and oncologist will likely discuss the best combination with you.

If rectal cancer has only spread to your liver, you may be able to be treated with chemotherapy directly into the artery leading to the liver. 

If the rectal cancer is too widespread to be operated on, you will be treated with chemotherapy, with the addition of biological therapy or targeted therapy. You may also need to undergo surgical procedures to manage any symptoms you experience, such as a complete blockage of the rectum.

Another type of treatment that patients who have deficiencies in certain DNA repair pathways may benefit from is immunotherapy. All rectal cancer, especially stages II, III, and IV, should be discussed with a multidisciplinary tumor board to determine the most appropriate treatment decisions for the type and stage of cancer.  

Recurrent rectal cancer

Recurrent cancer is cancer that comes back after initial treatment – usually within two to three years, but it could even be many years after your first cancer diagnosis.

Recurrence can occur at the site of the original primary rectal cancer, or it can occur in other organs.

If rectal cancer recurs in or near the original site, you may require more extensive surgery to remove it. This may be followed by radiation therapy and chemotherapy.

If your cancer recurs in other organs, the management required depends on the size and position of recurring cancer. If surgical resection is possible, cancer may be excised in combination with radiation therapy or chemotherapy. If surgery is not possible, you may need to have chemotherapy, radiation therapy, or use targeted therapy drugs. For some rectal cancer patients, immunotherapy may also be a treatment option.

Possible side effects of rectal cancer treatments

Side effects of rectal cancer treatments can range from mild to severe. Before starting treatment, it can be helpful to understand some of the more common side effects that you might experience during or after your treatment.


Rectal cancer surgery can include a range of procedures from a minimally invasive polypectomy to a major pelvic exenteration.

The recovery time for less invasive surgery is usually only a few days, while recovery from more invasive, complex surgery can take between three weeks to three months.

If you have undergone extensive surgery or your cancer was very close to the anus, you may require a permanent colostomy. There may also be damage to some of the structures near the rectum, such as the bladder, prostate, or uterus.

Radiation therapy

Radiation therapy can cause the following side effects:

  • Skin irritation, redness, or blistering at the radiation site

  • Nausea

  • Rectal irritation, which can cause diarrhea, painful bowel movements, or blood in the stool

  • Bowel incontinence

  • Bladder irritation that can mimic the symptoms of a bladder infection

  • Fatigue/tiredness

  • Sexual problems: erectile dysfunction in men and vaginal dryness in women

  • Painful adhesions between tissue near the radiation site

Most side effects typically get better with time once you’ve completed your radiation therapy; however, some may stay around. It’s a good idea to mention these to your doctor so that they can advise you on how best to manage any side effects.


The side effects of chemotherapy depend on the type you have. Chemotherapy targets cells that replicate quickly. Unfortunately, not only do cancer cells replicate quickly, but also the cells of your hair follicles, the cells lining your mouth and intestine, and the blood-forming cells of your bone marrow. 

Common side effects of chemotherapy include:

  • Mouth sores

  • Loss of appetite

  • Weight loss

  • Nausea and vomiting

  • Diarrhea

  • Nail changes

  • Skin changes

  • Fatigue

  • Bruising

  • Increased susceptibility to infection

  • Hair thinning/hair loss

Your doctor will prescribe medication to help manage any side effects you experience while undergoing chemotherapy. Most of the side effects will resolve once you have finished the treatment course. 

Targeted therapy

Targeted therapy is often used in rectal cancer in combination with chemotherapy. Side effects vary but can include fatigue, decreased appetite, mouth sores, high blood pressure, diarrhea, headaches, and increased risk of infection.


Immunotherapy is a less commonly used treatment for rectal cancer. However, when it is used, possible side effects include fatigue, coughing, nausea, diarrhea, skin rash, loss of appetite, joint pain, itching, and autoimmune-like side effects affecting other organs, such as the thyroid, lungs, heart, or gut.

Clinical trials

Clinical trials are studies that compare different treatments and evaluate how existing treatments compare to new ones. If clinical trials show a new drug to be superior to an existing drug, that drug may become the new standard of care.

During clinical trials, information and data are collected about the safety and efficacy of new drugs. All clinical trials are subject to ethics review.

Participating in a clinical trial may allow you the opportunity to receive treatment that you otherwise may not have access to.

Search for rectal cancer clinical trials here. 

What to expect after treatment

After finishing rectal cancer treatment, you’ll be relieved to have it over and done with, but likely also concerned about preventing cancer from coming back. This is a very normal concern. It may be helpful to create a care plan with your doctor that will include any necessary tests or investigations you may need going forward.

In most cases, your doctor will want to closely follow your progress for at least the next five years. You may need a clinical exam and investigations every three to six months for the first two years and then six-monthly for the next three years if your cancer has shown no signs of recurring.

Some of the tests and investigations that you may require on a regular basis are:

  • Colonoscopy/proctoscopy

  • Imaging, such as abdominal ultrasound scan, computed tomography scan or magnetic resonance imaging

  • Blood tests for tumor markers: Carcinoembryonic antigen (CEA) is a tumor marker that is released by some rectal cancers. The levels of CEA may be high when your cancer is diagnosed and then drop with treatment. Keeping an eye on your CEA levels is a good way to check that your cancer is in remission.

Increased risk can be due to genetics as well as lifestyle factors, such as obesity and diet. To reduce your risk, it is recommended that you follow the recommendations of the American Cancer Society Guidelines for the Early Detection of Cancer³ to screen for different cancers. If you have a family history of cancer, you should speak to your doctor to see if you need further evaluation. 

The lowdown

Treatment for rectal cancer differs depending on the stage of your cancer. The five typical treatments are:

  • Surgery

  • Radiation therapy

  • Chemotherapy

  • Targeted therapy

  • Immunotherapy

You may also require multiple treatments. Once you have completed your treatment for rectal cancer, you will need ongoing monitoring for at least five years to ensure that it doesn’t recur.

Other newer types of treatments are being tested in clinical trials. If you are diagnosed with rectal cancer, you may want to discuss with your doctor whether it would be helpful to join a clinical trial.

While all types of rectal cancer treatment have side effects, many will resolve once you have finished the course of treatment. There are ways to manage the more permanent side effects, so it’s worth discussing them with your doctor.

Have you considered clinical trials for Rectal cancer?

We make it easy for you to participate in a clinical trial for Rectal cancer, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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