What Causes Colorectal Cancer and Who’s At Risk?

Colorectal cancer is the fourth most common cancer diagnosed in the United States and accounts for over 50,000 deaths annually in the U.S.

A recent study in JAMA alarmingly showed that colorectal cancer is now the leading cause of cancer related death in people under the age of 50, and is the only major cancer where mortality rate in young people is increasing.

Colorectal cancer begins in the colon or the rectum (it can be referred to as colon cancer or rectal cancer, depending on where it starts). Colon cancer and rectal cancer are often grouped together because they have many features in common. Your colon is the final part of your digestive system: it re-absorbs fluids and processes waste from the body to prepare for elimination. Colon cancer develops from pre-cancerous polyps in the lining of the bowel. It usually takes many years for a polyp to turn into cancer.

We asked Greg Connolly, MD, a medical oncologist and hematologist with Rochester Regional Health’s Lipson Cancer Institute, about how to best prevent the disease and diagnose possible symptoms.

“The increase in colorectal cancer mortality in young patients is an outlier because we have observed significant decline in cancer- related mortality over the past 20 years for other major cancers like lung and breast cancer,” Dr. Connolly said.

What causes colorectal cancer?

The alarming increase in colorectal cancer in young people has brought renewed interest in understanding risk factors for colorectal cancer. It is likely that both genetic and lifestyle factors contribute to development of colorectal cancer.

Family history of colorectal cancer is a major risk factor for developing colorectal cancer. Other well established risk factors for colorectal cancer include:

• obesity
• sedentary lifestyle
• smoking
• excessive alcohol use
• environmental factors
• diabetes and insulin resistance

Prevention and early detection of colorectal cancer

There have been many exciting advances in the treatment of colorectal cancer which is wonderful for patients who face this challenging diagnosis, but prevention and early detection is the best approach to improving outcomes.

Colorectal cancer screening saves lives. This prevents cancer by eliminating polyps before they turn into cancer. Guidelines recently changed the starting age for colorectal cancer screening from 50 to 45 years of age due to the increased incidence of colorectal cancer in young patients.

A family history of colorectal cancer substantially increases one’s risk of being diagnosed with colorectal cancer. In addition, a small percentage of colon cancers are caused by inherited genetic abnormalities. These familial and genetic conditions can change screening recommendations. So it is helpful to know your family history and discuss how this may affect colorectal cancer screening recommendations with your medical professionals.

Other factors in reducing your risk of colorectal cancer include:

• getting regular physical activity
• maintaining a healthy weight
• avoiding smoking or other tobacco use
• avoiding excessive alcohol use
• eating healthy (less red meat and processed foods, more healthy fiber, fruits & vegetables)

Symptoms of colorectal cancer vs. other conditions

Even though there are effective screening tests for colorectal cancer allowing us to diagnose early stages, most patients with colorectal cancer present with symptoms. One common symptom is a change in bowel habits such as a change in appearance or size of the stool and constipation.

Other symptoms of colorectal cancer may include:

• blood in the stool
• abdominal pain
• bloating

Knowing your typical bowel habits and understanding any change from your typical bowel habits can be vital to recognizing a potential warning sign. If you have concerning symptoms that change from your baseline, you should always seek medical evaluation.

While it is true that many other medical conditions such as IBS, hemorrhoids or diverticulitis can present with similar symptoms as colorectal cancer, patients with IBS usually will not have blood in their stool even if they experience abdominal pain or constipation.

Some patients with colorectal cancer develop anemia (low red blood cell count) or iron deficiency The link is due to colon cancer causing bleeding into the bowel which over time can deplete the body of red blood cells and iron. Iron deficiency and anemia can cause fatigue, shortness of breath and other symptoms.

“There are many exciting advancements we can now offer patients who face the challenging diagnosis of colorectal cancer,” Dr. Connolly said. “Prevention and early detection are really important in improving outcomes. It is really important for patients to be aware of colorectal cancer risk and engage with their health care providers to ensure timely screening and healthy lifestyle choices to reduce the risk of colorectal cancer.”