Understanding Colorectal Cancer: Chemotherapy

Although colorectal cancer is often treated with surgery alone, chemotherapy may also be used. Chemotherapy treatment (often called “chemo”) doesn’t refer to one specific medicine but a group of many different medicines. Chemo medicines prevent cancer cells from growing and spreading. Chemo medicines do this by destroying cancer cells altogether or preventing them from dividing. Chemo affects the whole body because it goes through the bloodstream.

When is chemotherapy used?

Chemotherapy may be given either alone or along with radiation therapy. When given alone, it is given in a higher dose designed to destroy cancer cells. When given along with radiation therapy, it is delivered at a lower dose. This is designed to make the cancer more sensitive to the radiation.

Newer agents designed to inhibit tumor blood vessel growth are also being used for patients with advanced stage and metastatic colon cancer. A doctor can determine which agents are most appropriate for the treatment.

Chemotherapy is usually given through the vein, but some forms can be given by mouth. The medical oncologist will decide how many cycles or courses of chemotherapy are best.

The number of cycles of chemotherapy needed vary. It is relatively common for chemo treatment to begin 4 to 6 weeks after surgery and recovery.

Typically, after surgery, if you get chemo alone for colon or rectal cancer, you will receive between 6 and 12 cycles. When you receive chemo along with radiation, you may get 2 cycles alone and then 2 more with radiation. Then you may get another 4-8 after the radiation is done. 

Different oncologists use different schedules. The type of chemo drug being used is another factor. If you are considering chemotherapy for colorectal cancer treatment, you may also want to ask your doctor about clinical research trials for new chemotherapy drugs and combinations.

What can I expect from chemotherapy?

Chemotherapy not only weakens and destroys cancer cells at the site of the tumor, but throughout the body as well. Unfortunately, this means that chemo can unintentionally harm the development of normal cells like hair, nails, mouth, and digestive tract. 

The side effects chemo causes depend on the type of chemotherapy and how many cycles received. The most common side effects of chemo are:  

  • Nausea and vomiting
  • Fatigue or tiredness
  • Confusion, forgetfulness (“chemo brain”)
  • Decreased blood counts, sometimes with bruising, bleeding, or infection
  • Sores inside the mouth
  • Numbness in the hands and feet
  • Diarrhea, loose stool
  • Increased urgency to have a bowel movement or urinate

When chemotherapy is given at a lower dose, these side effects are less common. This sometimes happens when radiation is necessary too. However, patients often feel very tired. Irritation of the colon and anus can be a side effect, especially if there is a history of colitis, Crohn’s disease, or gastrointestinal problems. Make sure to tell the doctor if you have these conditions before starting chemo. There may be drugs available that can help with these side effects.

If you experience side effects, call your physician right away. It is better to address side effects right away, and there are numerous drugs available to help manage side effects.  Many side effects can also be managed by changing what and how you eat. If you experience side effects from treatment, visit Nutrition Tips for Managing Side Effects, or contact PearlPoint Cancer Support at guidance@pearlpoint.org to speak with an oncology registered dietitian.  

Chemotherapy can also cause infertility. Talk to your doctor as soon as possible. There may be ways to preserve your fertility, but they usually need to be done before starting chemotherapy.

How is chemo given? 

Chemo medicines come in different forms and can be given in different ways:

  • Intravenously (IV): As an infusion, the medicine comes through a thin needle (IV) in a vein in the hand or lower arm. An oncology nurse will insert the needle before each infusion and take it out afterwards.
  • Injection: As a single shot into a muscle in the leg, arm, hip, or under the skin in the fatty part of the stomach, leg or arm.
  • By mouth: As a pill or capsule, taken at home or at the doctor’s office.
  • Through a port: This is inserted in the chest during a short outpatient surgery. It is about the size of a quarter and sits right under the skin. A port is a small disc made of plastic or metal. A catheter (soft thin tube) connects the port to a large vein. The chemo medicines are delivered through a thin needle right into the port. Blood can also be drawn through the port. Once chemo is finished, the port is removed in a brief outpatient procedure.
  • Through a catheter in the chest or arm. This is a soft thin tube that is inserted into a large vein. This is done in a short outpatient surgery. The other end of the catheter stays outside the body. This is similar to having a port.

If you have a catheter or port, your medical team will tell you to be sure to watch for signs of infection.

What’s the advantage of a port or catheter?

Many doctors recommend getting a catheter or port. It makes chemotherapy easier and more comfortable, as patients don’t have to be restuck each time, like with an IV or injection. Some colorectal cancer patients have a portable pump attached to the port or catheter. This controls how much and how fast the chemotherapy medicine goes in. The pump can either be internal (implanted under the skin during a short outpatient procedure) or external (carried by the patient). Once chemo is done, the pump is taken out.

How often will I have to have chemo? 

Your oncologist will set your treatment regimen. Every chemo regimen is made up of cycles. This means a period of treatment followed by a period of recovery. For example, you may get chemo one day and then have a few weeks of recovery with no treatment. That would be one cycle. Or you may get chemo for several days in a row and then have a recovery period. Several cycles make up a complete chemotherapy regimen.  

The number of cycles in a regimen and the length of each regimen vary from patient to patient. A lot depends on the medicines used. However, most regimens take 3 to 6 months to complete. A typical routine is treatment every 3 weeks. 

You can get chemotherapy in a variety of settings: at a hospital, in a doctor’s office, or in a clinic. You may even get chemo at home if you are taking chemo in a pill form or you have a portable pump.  

If you take chemo in a clinic, hospital, or doctor’s office, you usually go home between treatments. In some cases, you may stay in the hospital to be monitored. This is especially true if your immune system isn’t working as well as it should be. Your doctor will explain where you’ll be getting your treatment. 

What should I bring to my chemo appointment?

A chemotherapy treatment at a hospital or clinic can take anywhere from one to several hours. Although many chemo treatment areas have televisions and magazines, you may want to bring something to help pass the time. Ideas include: 

  • A laptop
  • Knitting, needlepoint, or crochet
  • A thick novel
  • Crossword or other puzzle book
  • Sketchbook and pencils
  • Cards or board games (if you have someone to play with)
  • MP3 player or portable CD player to listen to music
  • Paper and pens to keep a journal or write letters

Is there anything I should be thinking about before I start chemotherapy?

Chemotherapy treatment can drain most of your energy. This is a major process the body is going through. There are some things you should take care of before you start chemo:

  • Get your teeth cleaned and get a dental check-up. Chemo weakens the immune system, so you may be more vulnerable to infections caused by bacteria that are dislodged during teeth cleaning.
  • Get any heart tests (like an EKG) that the doctor recommends.
  • If you’re a woman, get a Pap smear if you’re overdue. Chemo can alter the results of Pap smears, so it’s best to get one beforehand.
  • Find someone to help around the house. Chemo causes extreme fatigue. Line up someone to help with chores such as cleaning, grocery shopping, carpooling, and cooking. Don’t be too afraid to ask for help.
  • Join a support group if that sounds helpful. 
  • Find out ahead of time what you should and shouldn’t eat or drink on treatment days. Tell your doctor all the vitamins, supplements, over-the-counter, and prescription medicines you take.
  • Talk to your doctor about hair loss. Most chemo medicines cause some amount of hair loss. If you plan on wearing a wig, you might want to go ahead and get it so you can match it to your hair color and style.

If you need assistance preparing for chemotherapy, contact PearlPoint Cancer Support at guidance@pearlpoint.org or (877) 467-1936 X 101 or by using the LiveChat function at the bottom, right corner of your screen. We can schedule a time for you to speak with a registered dietitian or a cancer support professional.

Return to list of treatment options.

Back to “Understanding Colorectal Cancer: An Introduction”