Understanding Colorectal Cancer Side Effects

Colorectal cancer is becoming more common, especially among younger adult populations. This fact sheet will cover both signs of potential colorectal cancer and side effects of its treatment:

• Signs of possible colorectal cancer
• Why colorectal screening is important
• Side effects from colorectal treatment
• Recovering from colon cancer surgery

Common Signs of Colorectal Cancer

There are certain signs that can show that you have colon cancer. Note that these can also indicate other issues besides cancer, but include:

• Diarrhea or constipation that lasts longer than a few days
• Bright red blood in the stool or very dark brown or black stools
• Discomfort or bloating in the abdomen, feeling of cramps, gas or pain
• Feeling that you need to empty your bowels even after having gone
• Ongoing weakness or fatigue
• Losing weight without trying

If you or a loved one show any of these symptoms, it is recommended to schedule screening to determine whether it is cancer.

Importance of Screening

Because colon cancer can develop without showing any signs, it is recommended to get screened regularly and by a certain age.

A colonoscopy is the most typical way to screen for colon cancer. In this procedure, a long, flexible tube is inserted into your colon, during which you will usually be under sedation. There will be a prep time in the days before when you will have a reduced diet.

Rates of younger people getting colon cancer are rising. You should get colon cancer screening once you turn 45, and regular screening after this, depending on your family history and risks. For older adults above the age of 76, the rate of screening may be less.

Speak with your doctor about how often you should get screenings done. For more, read our fact sheet “Colorectal Cancer: Understanding Risk Factors and Screening.”

Side Effects of Treatment

The most common way that colorectal cancer is treated is surgery. This may be followed by chemotherapy or radiation. In some cases, chemotherapy may be used before surgery.

Chemotherapy side effects include the following:

• Nausea and vomiting, loss of appetite and diarrhea
• Weakness and fatigue
• Hair loss
• Neuropathy (tingling in hands and feet)
• Increased risk of infection, easy bruising or bleeding
• ‘Brain fog,’ or changes in memory or thinking

Radiation therapy side effects include the following:

• Diarrhea, constipation, cramping in the abdomen and feeling gassy
• Nausea and loss of appetite
• Irritated skin in the treated area
• Burning sensations during urination, or having to urinate more often

Your health care team can help with these side effects. Try to write down when you feel certain ways. Do not take any extra medication without checking with your team.

Side Effects of Healing From Surgery

Colorectal surgery involves either removing part or all of the colon. This is called either a partial or total colectomy. This procedure is minimally invasive, which means that only a few small incisions are used.

Although the cuts are small, the cuts go into layers of the abdomen, and it can take weeks or months to fully heal. In the first weeks, you will be required to eat a careful diet and restrict physical activity. Early on, your stomach and intestines may feel like they are shifting back in forth inside of you. You may develop scars over the cuts that may require care.

It is important to follow the guidelines of your surgeon and health care team closely.

Sometimes, a colostomy bag is used to collect waste through a hole in the abdomen. This can be temporary, to allow the intestine to heal. Or it can be permanent if the tumor too close to the anus to save the muscles of the sphincter that cause it to close. However, most patients will not require one. If you do require one, ask your team how to clean and handle the bag and opening.