5 Colorectal Cancer Symptoms And 7 Risk Factors

Colorectal Cancer Symptoms
Colorectal Cancer Symptoms

Colorectal cancer is the third most common cancer worldwide, accounting for 9% of all cancer incidences, and the fourth most common cause of death.1 It is slightly more common in men, and black men at that.2

[pullquote]It is the third most common cancer worldwide, and fourth most common cause of death. It is also common among black men.[/pullquote]


Until recently, colorectal cancer was thought to affect mostly people above 50. However, we know now that the cancer incidences are dropping in those above 50 but rising in the younger population. As the cancer is often detected in the younger generation only after it has reached an advanced stage, knowledge about colorectal cancer symptoms and risk factors can make all the difference.3 Colorectal cancer is silent in most cases, with the cancer lurking anywhere in the 5- to 8-feet-long passage from the colon to the rectum. It doesn’t present any tell-tale symptoms in the initial stages. This is what makes screening essential. In an advanced stage, the symptoms of colorectal cancer include:

1. Change In Bowel Habits

 You may notice a change in your bowel habits, which may last more than a few weeks. You may feel that your bowel has not been emptied entirely. You may try to pass stool several times a day, but that is unlikely to rid you of the sensation.


[pullquote]If your stool has suddenly become narrow or has a lot of mucus or blood, along with alternating episodes of diarrhea and constipation for a few weeks, get a screening test.[/pullquote]

2. Change In Bowel Movement

You may pass watery stool like in diarrhea. Or you may have difficulty passing stool like in constipation. Often, episodes of diarrhea and constipation may alternate.


3. Narrow Stool

The stool might itself become narrow because of blocks in the colon and the rectal passage.

4. Blood And Mucus In Stool

If you don’t have piles or irritable bowel disorders, persistent blood in your stool or toilet bowl after a bowel movement requires a checkup. Bright red blood may indicate a cancer in the rectum or in the last part of the colon, while dark or black stool indicates a cancer higher up in the colon. There might be mucus too.


Some amount of mucus in your stool is not uncommon. But a persistently large amount of mucus in the stool, along with blood or change in bowel habits, indicates an infection or inflammation. Your body produces a lot of mucus to heal itself.

5. Abdominal Pain, Bloating, And Nausea

You may experience bowel obstruction, which causes pain, discomfort, bloating, nausea, and vomiting after eating. The symptoms may be present at every meal over a few weeks. This in turn reduces appetite and food intake, leading to weakness, fatigue, and weight loss.


Colorectal Cancer Symptoms Vs Piles, IBS, and IBD Symptoms

Colorectal cancer might be all the more difficult to detect because it shares similar symptoms with these conditions. This is what makes screening for colorectal cancer so crucial after 50 and in some cases even earlier.

  • Piles or hemorrhoids also cause bleeding during bowel movement. But the bleeding is often erratic. With colorectal cancer, however, the bleeding can persist over a few weeks or occur together with pain.
  • Irritable bowel syndrome (IBS) can cause diarrhea, constipation, and abdominal cramping. But if these are accompanied by bleeding, whether or not you have piles, you should get medical help.
  • Irritable bowel disorders, like ulcerative colitis and Crohn’s disease, have symptoms like abdominal pain, diarrhea, and bleeding. Patients often complain that they haven’t been able to empty the bowel completely and feel the need to try again and again. These patients also suffer weight loss. IBD patients who have had colitis for 8 years or have 1/3 or more of their colon involved are at high risk and should screen for cancer. It is very difficult to differentiate between IBD and colorectal cancer on the basis of symptoms.4

Risk Factors Of Colorectal Cancer

About 75% of all colorectal cancers are caused by sudden gene mutations and environmental or lifestyle risk factors.5


1. Too Little Vegetables And Fruits

Lack of fiber in your diet often leads to toxic waste building up in the colon. These release reactive molecules called free radicals which then damage cells and trigger inflammation. If you don’t eat enough vegetables, leafy greens, and fruits that have antioxidants like flavonoids and carotenoids to fight the free radicals, you are making yourself more vulnerable to cancer risk.

[pullquote]Eat leafy greens, colorful veggies and berries, fibrous whole grains, and crushed garlic to prevent cancer.[/pullquote]


Lack of vitamin B9 or folate, vitamin D, and calcium has been held responsible for increased cancer risk.6 7 Folate enables new cell and tissue formation and keeps red blood cells active and healthy.

Magnesium-rich foods like spinach and pumpkin seeds help too. Having garlic daily is also considered effective in lowering cancer risk. Here are a few other anticancer foods you should include in your diet.

2. Too Much Red Or Processed Meat

[pullquote]Pork, beef, veal, and lamb contain heme iron, which increases the risk of colorectal cancer.[/pullquote]

Red meat adds to your risk of colorectal cancer, especially colon cancer. When heated at a high temperature, these animal fats and proteins break down into certain cancer-causing amines and hydrocarbons. Moreover, red meat like pork, veal, beef, and lamb contain heme iron, which is associated with a higher risk of colorectal cancer. Grass-fed beef, however, has cancer-fighting compounds.

[pullquote]People who eat the maximum amount of processed meat have a 17% higher risk of colorectal cancer than those eat it rarely.8[/pullquote]

Processed meat like cold cuts is even more unsafe. This is one of the reasons this cancer is so common in affluent and developed countries.9

3. Too Much Alcohol

[pullquote]Men should drink only 2 units of alcohol daily and women should drink 1. If you drink over 3.5 drinks a day, you have a 52% higher risk of colorectal cancer.[/pullquote]

Onset of cancer, especially in the last or the distal part of the colon, is earlier in people who drink than in the general population.10 Sadly, this is true even for light drinkers.

You have a 21% increased risk of colorectal cancer if you drink more than 2 drinks. Any more than 3.5 drinks a day, you are 52% more likely to get colorectal cancer. For every 10 g you pour down your throat, your cancer risk leaps by 7%.

Alcohol Breaks Down Into Toxic Substances

Alcohol breaks down into acetaldehyde, which accumulates in the colon. It can degrades the folate vitamin in the mucosal cells lining the inside of the colon, by up to 48%.11

[pullquote]East Asians have a higher risk of colorectal cancer due to their faulty alcohol metabolism.[/pullquote]

The acetaldehyde further damages the DNA and generates reactive molecules called free radicals that damage cells and increase the risk of cancer. Acetaldehyde may also function as a solvent and help cancer-causing molecules penetrate the mucosal cells of the colon.

This negative effect of acetaldehyde accumulation is even more pronounced in East Asians. Some of them have a mutation in the alcohol metabolism gene as well as in the gene that transforms acetaldehyde into non-toxic byproducts.12 As a result, the risk of colon cancer from alcohol is higher in this population.

4. Smoking Tobacco

In the United States, of every 100 casualty of this disease, 12 have smoking to blame.13 A Norwegian study reports that women who smoke are 20% more likely to get colon cancer than their counterparts who have never smoked.14

[pullquote]For passive smokers, screening tests should be done at 40.[/pullquote]

Sadly, even passive smokers can get colorectal cancer and earlier than others. In their case, the screening test should be done at 40.15

Nicotine Spreads The Cancer

Tobacco contains carcinogenic substances like nicotine and its compounds, including NNK. These can induce cancer cell growth and make the cells travel across the body, affecting other areas.16 The risk decreases when you quit smoking. And the younger you quit, the better.17

5. Physical Inactivity And Overweight

[pullquote]About 25 to 33% of colorectal cancer incidences are caused by physical inactivity and excess body weight.[/pullquote]

Physical inactivity and excess body weight together account for about 25 to 33% of colorectal cancer incidences, and overweight men have a higher risk of colon cancer than overweight women.18

This can be changed. Moderate or intense exercising can reduce the risk of colon cancer by 13 to 41%.19 Exercise increases the metabolic rate and oxygen intake and improves the stretching and contraction of the gut muscles. This keeps the gut healthy and efficient.

6. Diseases And Inherited Conditions

Colorectal cancer is mostly environmental in nature. Long exposure to environmental risk factors makes the DNA mutate suddenly in a few places and trigger the growth of cancerous cells. But inherited genes also play a big role.

[pullquote]About 20% of colorectal cancer patients have a family history of the cancer.[/pullquote]

Up to 20% of colorectal cancer patients report that they have family members with colorectal cancer. Of these, 5 to 10% have two hereditary cancer-causing conditions: familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). The rest get colorectal cancer because of shared environmental factors.

[pullquote]A person with classic FAP develops colorectal cancer when they are about 39 years of age.[/pullquote]

If a parent has FAP, you have a 50% risk: If even one parent has benign tumors in the colon, a genetic condition known as familial adenomatous polyposis, there’s at least a 50% chance of your getting the condition. If not treated, FAP always progresses to colorectal cancer. In the classic form of the disease, the polyps start developing when you are in your mid-teens. If this is not treated, you may have more than a 100 polyps by the age of 39. This is the average age a person with the classic FAP develops colon cancer. Sometimes, the development of the polyps may be delayed. This is called attenuated FAP. In this case, your colorectal cancer onset may get postponed till you are 55.20

[pullquote]People with Lynch syndrome are mostly diagnosed with colorectal cancer when they are 45.[/pullquote]

Having HNPCC in the family increases risk by 50%: Say your sibling has been diagnosed with Lynch syndrome or hereditary nonpolyposis colorectal cancer (HNPCC). Because you hail from the same set of parents, one of whom obviously has this condition, you also have a 50% increased risk of inheriting Lynch syndrome. It doesn’t present any symptoms in itself but makes you vulnerable to a number of cancers, chiefly of the colon and the rectum. If you are a woman, Lynch syndrome also puts you at risk of uterine and ovarian cancer. Lynch syndrome accounts for about 3 to 5% of the total incidences of colorectal cancer in the United States. In most people with this condition, colorectal cancer is diagnosed around 45 years of age.21 22

Having irritable bowel disorders: If you have ulcerative colitis and Crohn’s disease, stay alert. There’s a 4 to 20 times risk of the inflammatory condition worsening into colorectal cancer.23

7. Age Above 50 Years

Both men and women are at a high risk of colorectal cancer once they cross 50. In fact, 90% people with colorectal cancer are 50 or older, with many more people in the 60–79 age bracket than in the 40 or below bracket.

[pullquote]50 used to be the risky age, but now the millennials are at high risk.[/pullquote]

As you grow old, gene mutations due to physical, chemical, and biological risk factors start effecting changes in your body. Plus your cell repair mechanism becomes weaker with age. As a result, there’s an increase in new colorectal tissue growths, both benign and malignant. But there’s a delay in the death of these cells. So the cancer grows and spreads rapidly.24

The numbers, however, are rapidly changing, with more young people affected by the disease. Now, those born in 1990 have 2 times the risk of colon cancer and 4 times the risk of rectal cancer than those born in 1950.25 This is possibly because of greater exposure to environmental or lifestyle risk factors. Children are not entirely immune either if there’s a family history of colorectal cancer, colon tumors, and Lynch syndrome.

Screening Tests And Lifestyle Changes Are Mandatory

[pullquote]Get a colonoscopy or fecal occult blood test once you turn 50.[/pullquote]

While you can prevent colorectal cancer with these 5 lifestyle changes, screening tests are mandatory once you turn 50. This is the average age when the disease starts showing itself. Go for colonoscopy and other tests to detect occult or hidden blood in stool. Sometimes, you can’t see any trace of blood with the naked eye.

The colonoscopy will find if there are polyps or abnormal tissue growths in your colon. These are the precursors to the cancer. Further tests can determine whether these polyps are benign or malignant.