Treatment

People with rectal cancer often have radiation therapy along with chemotherapy to shrink their tumor before surgery. This makes the tumor easier to remove from the small space in and around the rectum, and it decreases the chance that the cancer will return. 

If your cancer has spread to other parts of your body, radiation therapy may also be helpful for treating those specific spots.

External-beam radiation therapy (EBRT) aims high-energy X-rays or other types of radiation at your body to kill cancer cells. Three main types are used for rectal cancer: intensity-modulated radiation therapy, proton therapy and intraoperative radiation therapy.

Intensity-modulated radiation therapy (IMRT)

For rectal cancer, doctors most often use IMRT. 

• IMRT uses a computer-controlled linear accelerator that moves around you to deliver X-ray radiation. 
• It shapes the beams and aims them at the tumor from several angles. 
• The intensity of the beams can be adjusted to lessen the dose that reaches sensitive normal tissue. 
• You will most likely get chemotherapy at the same time (called chemoradiation) because chemo can make cancer more sensitive to radiation.

Learn more in our radiation oncology section.

Proton therapy

Proton therapy is a unique form of EBRT that targets protons at tumors to kill cancer cells. 

• Proton therapy may significantly limit radiation exposure to surrounding healthy tissue near the rectum, such as the bowel and bladder. 
• This may reduce side effects from treatment and allow for a shorter course of treatment compared with X-ray radiation therapy.
• Proton therapy may be particularly useful if you have recurrent tumors and had radiation therapy to the same area in the past.

The SCCA Proton Therapy Center is the only proton facility in the Pacific Northwest. Learn more about proton therapy for rectal cancer.

Intraoperative radiation therapy (IORT)

Your SCCA team may recommend IORT if:

• You have locally advanced rectal cancer that is attached to normal structures (such as nerves or blood vessels) that cannot be removed. 
• You have recurrent tumors. 

IORT is a fast and effective form of radiation therapy that uses electron-beam radiation during surgery. 

• Your surgeon moves normal structures out of the way to expose the area for this precise, high-dose treatment.
• It takes only a few minutes to deliver and uses only a fraction of the total radiation given over a traditional multi-week course of external-beam radiation. 

University of Washington Medical Center (UWMC) is the only hospital in the WAMI region (Washington, Alaska, Montana and Idaho) to offer this treatment. Learn more about IORT.

Your doctors may recommend chemotherapy:

• Before surgery, along with radiation therapy, to help shrink your tumor so it’s easier to remove, which improves results in people with advanced disease
• After surgery to help prevent your cancer from coming back
• As your first treatment, instead of surgery, if your cancer has already spread to another area of your body at the time it is diagnosed

Usually chemotherapy medicines are given by infusion into a vein. Some are taken by mouth in pill form. 

Your SCCA team will talk with you about the specific drugs we recommend for you, how you’ll receive them, your treatment schedule and what to expect. We’ll also explain how to take the best possible care of yourself during treatment and after, and we’ll connect you with medical and support resources throughout SCCA.

Learn more about chemotherapy in our medical oncology section. 

Most people with rectal cancer have surgery to remove their cancer. Often they have several weeks of radiation therapy and chemotherapy first, which improves disease control.

As an SCCA patient, you’ll have surgery performed by a UW Medicine surgeon specially trained and board certified in colorectal surgery. 

Your exact procedure will depend on factors like the stage and location of your cancer as well as your overall health, weight, height and preferences. You and your team will discuss your options and decide together what is best for you.

Local excisions

If your cancer was found at a very early stage, it may have been removed at the time of your colonoscopy (polypectomy). 

• Removal during colonoscopy may be all you need, or you may need a deeper local excision of the rectal wall.
• For early rectal cancer that’s small enough and low enough in the rectum, our surgeons are specially trained to remove a full-thickness disc of the rectal wall and sew the wall closed through the anus (called transanal surgery). This can avoid the need for larger surgery.  
• These decisions are individualized and often very complex. Your surgeon will talk with you about what they recommend for you and why.

Mesorectal excisions

Most people need surgery to remove the cancerous segment of the rectum (proctectomy with total mesorectal excision).

• The surgeon takes out the cancerous segment and also nearby fatty tissue and lymph nodes, which are checked for cancer. 
• This surgery has significantly reduced the rate of recurrence of rectal cancer in the pelvis. 
• Our surgeons typically perform the procedure laparoscopically (through small “keyhole” incisions). They may also use robotic assistance during surgery for precision movements.

After the cancerous segment of your rectum is removed, your surgeon may also perform an anastomosis or a colostomy.

Anastomosis

The surgeon sews or staples the healthy parts of your intestine together so stool can move out of your body.

It may take several operations to achieve this end result. During the process, you may temporarily need an ileostomy. 

• The surgeon creates an opening (stoma) in your abdomen and attaches the open end of your small intestine (ileum) to it on the inside. 
• A bag is attached to the skin on the outside to collect waste. This allows your new anastomosis to heal. 
• A few months after the rectal surgery, the ileostomy can usually be reversed with a much smaller operation.

Colostomy

Sometimes in order to completely remove the cancer, surgeons cannot save the anal sphincters. 

• Instead of an anastomosis between the colon and the rectum or anus, you may need a permanent colostomy.
• The open end of your colon is attached to a stoma on the inside, and a bag is attached on the outside.

We can help you learn how to care for your colostomy and adjust so you can go on with normal activities comfortably. We have a specially certified wound ostomy nurse who understands the physical and emotional impact of ostomies and can work closely with you, your family and your doctors.

Learn more about surgical oncology.

Targeted therapies are newer cancer treatments that work more selectively than standard chemotherapy. They target a gene or protein responsible for allowing cancer to grow, they seek out and damage cancer cells, or they prompt your immune system to attack particular cells (also called immunotherapy). 

Targeted biological therapies use substances, like antibodies, that come from living organisms, or versions of these substances made in a laboratory.

These medicines are important if you have colorectal cancer that has spread to other parts of your body (advanced or metastatic cancer).

Biological therapies for colorectal cancer include: 

• Bevacizumab (Avastin) — which starves tumors by stopping growth of blood vessels that nourish tumor cells (anti-angiogenesis therapy)
• Cetuximab (Erbitux) and panitumumab (Vectibix) — which block a normal protein (epidermal growth factor receptor) on the surface of your cells that may contribute to cancer growth (anti-EGFR therapies, or EGFR inhibitors) 

Learn more about targeted therapy in our medical oncology section.