Skip to content

Most People Who Get Colon Cancer Have Bowel Movement Issues First

Learn what to know about colon cancer and signs that indicate you could have it
FACT CHECKED BY Emilia Paluszek

Talking about poop isn't something most people enjoy openly discussing, but it's an important topic to talk about with a healthcare provider. Paying attention to your bowel habits and talking to a doctor about them can be life-saving. Knowing if there's blood in your stool or something isn't right is an issue your physician should know about because it could indicate a larger problem like Crohn's disease, colitis or colon cancer, which is a concern since cancer is the second leading cause of death in the United States and early detection is key to beating the odds. The American Cancer Society estimates there will be 106,180 new cases of colon cancer and 44,850 new cases of rectal cancer for 2022, so knowing the symptoms can save your life.  

Dr. Jagdish Khubchandani, MBBS, Ph.D., a professor of public health at New Mexico State University tells us, "Colorectal cancers are among the top five common cancers detected in the U.S. adult population. Men and women have a nearly 5% risk of getting this type of cancer in their lifetime. Unfortunately, many people will find out about the cancer only when it has grown and spread. For several others, the cancer is detected early in the form of precancerous growths or polyps that are easier to treat and remove than cancers that have grown in size and have spread. The U.S. The Preventive Services Task Force recommends screening for colorectal cancer for all people aged 50 to 75 years."

Dr. Khubchandani adds, "The tricky part about symptoms for colorectal cancer is that many times people won't have many symptoms. Or people can have symptoms only when the cancer has grown rapidly and spread, or the symptoms are not specific to colorectal cancer, or the symptoms may raise alarm when a person really may not have colorectal cancer. Still, the symptoms can be grouped into following categories below. As always, please consult your physician for medical advice. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


What to Know About Colon Cancer

Woman holding model of human intestines in front of body.

Dr. Stephanie Pannell, a colorectal surgeon at The University of Toledo Medical Center and assistant professor of surgery in the UToledo College of Medicine and Life Sciences in Toledo, Ohio tells us, "Colorectal cancer is the fourth most common type of cancer in the United States and one of the leading causes of cancer death. Often people will not have any symptoms until later in the progression of the disease and the cancer has become more advanced. However, with regular screenings and early diagnosis, colon cancer can be very treatable."

James H. Tabibian, MD, PhD, FACP, FASGE.  Dr. Tabibian is Physician Specialist, GI-Invasive, Director of Endoscopy, Department of Medicine at Olive View-UCLA Medical Center and Health Sciences Clinical Professor at David Geffen School of Medicine at UCLA says, "Colorectal cancer is common in both men and women and can develop without symptoms up until late stages of the disease. In the United States, aside from skin cancer, it is the fourth most commonly diagnosed cancer and the second leading cause of cancer death overall. It is estimated that 1 in 25 individuals will develop colorectal cancer during their lifetime, and it is the cause of over 50,000 deaths per year in the United States."


Signs of Colon Cancer to Watch Out For

open the bathroom door, go to toilet

Dr. Tabibian says, "Colorectal cancer often does not have any early signs, but when it does, it's typically a change in bowel habits (such as new onset difficulty/straining to have a bowel movement or much thinner stools than before), blood in or on the stool (the poop, that is), or unexplained weight loss. Whether a patient develops these or other signs depends in large part on where the cancer is located; for instance, whether it's at the beginning of the colon, in the rectum, or somewhere in between.  Of note, these signs don't always indicate that there's cancer, but they should set off a red flag which signals the need for further evaluation."

Dr. Pannell adds to pay attention to the following:


Colon cancer is erosive and can cause very slow blood loss that may not be obvious in your stool. A large majority of these patients will present with a low hemoglobin also known as anemia. Unfortunately, like with other signs, this is a later symptom because there are no early signs.. Every anemic patient should have a colonoscopy.

-Changes in stool caliber

Large tumors that block the colon can cause the stool to be thin. Often, we describe this as a pencil-like stool.

-Dark tarry stools or bright red blood in stool

While colon cancer can cause bleeding that's not obvious, it can also result in stool that is dark and tarry or show as bright red blood in the stool. There are a number of things that can cause blood in the stool, but it can also be an early symptom of colon cancer. Any time you have rectal bleeding you should schedule an appointment to discuss it with your physician."


Bowel Habits and Movement

upset woman in toilet by diarrhea, constipation, hemorrhoids, piles

Penn Medicine says, "A bowel movement is the last stop your food makes as it goes through your digestive tract. Sometimes called stool or feces, your poop is what's left of your food and drink after your body absorbs important nutrients. What and how you eat affects your digestive system, and sometimes, your bowel movements can change simply because of changes in your diet. Other times, changes in bowel movements signify something more serious. What's "normal" depends on each individual person — but there are some signs you can look for that mean something may be off [like change in color, frequency, consistency]. 

According to Dr. Khubchandani, "Changes in bowel movement, habit, frequency, or content are a common symptom of colon cancers as colon is involved with bowel. Symptoms may manifest as constipation, diarrhea, or altered stool volume. Sometimes, individuals may also experience tenseness or the urge for a bowel movement or defecation not relieved by having one instance of defecation or bowel movement. Also, these symptoms should be lasting more than just a few days to avoid confusion with common bowel problems (e.g., gas, occasional constipation, indigestion, etc.)."



man prostate cancer, premature, ejaculation, fertility, bladder problem

Dr. Khubchandani explains, "Depending on the stage of cancer, bleeding in stool may be an early warning sign too. This could manifest as bleeding from the Rectum or blood mixed with stool making it dark colored (e.g., black or brown). This is because colorectal cancers can spread throughout the lower intestine causing lesions that cause bleeding and mixing of blood in stool. Such bleeding is often considered as a major cause of anemia in individuals or weakness when the colon is involved." 

According to Cedars Sinai, "The main thing to know about healthy poop is that blood in the stool could indicate a serious health problem. "Blood should be the first thing you look for in your stool," says Dr. Mark Pimentel, a gastroenterologist at Cedars-Sinai. Blood in the stool (also known as rectal bleeding) could be a marker of cancer or other health issues, such as Crohn's disease or colitis."



stomach pain

Dr. Khubchandani reveals, "Along with bleeding, pain can be an early symptom of colorectal cancers. Predominantly, pain in the abdominal area, cramping, bloating (if lymph nodes are involved) or aces and swelling or distension of stomach area or abdomen should be considered as symptoms of colorectal cancer along with diagnostic tests and other symptoms."

Cleveland Clinic states, "Stools should be soft and pass easily. Hard, dry stools might be a sign of constipation. You should notify your healthcare provider if constipation lasts longer than two weeks. Also, if you have nausea, vomiting, abdominal pain, and have not been able to pass gas or stools, this could mean that there is an obstruction (blockage). You should tell your provider or go to your local Emergency Department."


Systemic and Non-Specific Symptoms

woman with upset stomach drinking tea

Dr. Khubchandani tells us, "Many common symptoms are indicators of different types of cancers such as weakness and fatigue and weight loss without trying to lose weight. Other symptoms may depend on cancer spread (e.g., breathing difficulty for spread into lungs), nausea, jaundice, and vomiting (e.g., if cancer spreads to the liver), or cognitive difficulties, confusion, headache, vision or speech problems, and seizures (e.g., when cancer spreads to the brain or spinal cord).

With simple measures, one can reduce the risk of colorectal cancers. Some factors are not modifiable (e.g  race, age, family history, etc). However, there are other factors to be considered in prevention such as obesity, smoking, and physical inactivity. The role of diet is always being investigated, but it is advisable to add more fibers, fruits, and vegetables to the diet."


Risk Factors

Dr. Pannell explains, "The main risk factors for colon cancer are having a family history of the disease and advanced age. That said, about 75% of people have no risk factors. That's why regular screening is so important, even for people who don't have any known factors that put them at a higher risk."

Dr. Tabibian adds, "The risk of developing almost every cancer increases with age, and colorectal cancer is no exception to this, as suggested by the age-based recommendation for screening in the general population (now starting at age 45). But there are numerous other risk factors as well for developing colorectal cancer, including a personal or family history of colorectal cancer or precancerous colorectal polyps, a genetic/inherited cancer syndromes such as familial adenomatous polyposis (FAP) or Lynch syndrome, inflammatory bowel disease (in particular ulcerative colitis or Crohn's colitis), and lifestyle factors, such as a diet low in fruit, vegetables, and/or fiber, obesity, tobacco use, and others. Thus, there is no one-size-fits-all approach to colorectal cancer screening, and instead an individualized assessment is crucial."


Colon Cancer Can Be Successfully Treatable

Gastrologist. Doctor's office. Doctor gastroenterologist with probe to perform gastroscopy and colonoscopy

Dr. Tabibian emphasizes, "Colorectal cancer is very treatable, especially when diagnosed at an early stage.  In fact, it can be completely removed just by colonoscopy—without needing any chemotherapy, radiation, or surgery—if found early enough. When diagnosed at a late stage, it can still be treated, but not always is it curable."

Dr. Pannell says, "The earlier you find the cancer the higher the survival rate. The American Cancer Society quotes the five-year survival rate being 91% if the cancer is only localized. If it has only spread to the lymph nodes, the five-year survival rate is 72%. If the cancer has spread to other organs, the average five-year survival rate goes down to 14%. Compared to many of the other cancers, colon cancer is very treatable and even preventive if we follow the screening guidelines."

Heather Newgen
Heather Newgen has two decades of experience reporting and writing about health, fitness, entertainment and travel. Heather currently freelances for several publications. Read more about Heather
Filed Under