Colon cancer, also known as colorectal cancer, refers to the uncontrolled growth of cells that begins in the large intestine, specifically the colon or the rectum. It typically develops from small, non-cancerous growths called polyps that can become cancerous over time, which is why screening is so important. While many people with the disease may not experience symptoms in its earliest stages, the appearance of persistent changes can offer a warning sign. Recognizing these indicators is the first step toward seeking diagnosis and treatment. This article details the common physical and systemic changes that can suggest the presence of colon cancer.
Subtle Shifts in Bowel Habits and Function
The presence of a growing tumor within the colon can interfere with the normal movement and processing of waste, leading to noticeable alterations in routine. These shifts often involve a change in the frequency or consistency of bowel movements that lasts for more than a few days. A person may experience persistent constipation, where stools are difficult to pass, or conversely, frequent episodes of diarrhea.
The tumor mass can narrow the passageway through the colon, visibly changing the shape of the stool. This often results in stools that appear much thinner than usual, sometimes described as pencil-thin or ribbon-like. When the tumor is located lower down, particularly in the rectum, it can create a sensation known as tenesmus. This is the feeling of constantly needing to have a bowel movement, even immediately after one has occurred.
Tumor growth can also cause ongoing abdominal discomfort because it begins to obstruct the passage of gas and waste. Individuals may experience persistent cramping, gas pains, or bloating. This discomfort can be localized to a specific area of the abdomen and may be accompanied by a feeling of fullness.
The location of the tumor influences the type of functional symptoms that emerge. Tumors found in the wider right side of the colon might grow quite large before causing obstruction or pain. Conversely, tumors in the left side of the colon or the rectum, where the diameter is smaller, tend to cause symptoms like narrowed stools and changes in frequency much sooner.
Indicators of Internal Bleeding and Anemia
A common systemic consequence of a colon tumor is chronic, low-level blood loss over a long period. Cancerous tumors develop fragile blood vessels prone to bleeding. This bleeding can manifest in several ways, depending on the tumor’s location within the digestive tract.
If the tumor is located lower in the rectum or sigmoid colon, the blood may still be fresh when passed, resulting in visible bright red blood on the toilet paper or mixed in with the stool. If the bleeding originates higher up in the colon, the blood is digested as it travels through the intestines. This causes the stool to appear dark red or black, taking on a tarry consistency known as melena.
The consistent, long-term loss of blood depletes the body’s iron stores. This chronic loss frequently leads to iron-deficiency anemia, a condition where the body lacks enough healthy red blood cells to carry adequate oxygen. The resulting lack of oxygen delivery to tissues manifests as weakness and fatigue.
Anemia can also lead to physical signs such as pallor, or unusual paleness of the skin, and sometimes an increased heart rate. Another systemic symptom is unintended weight loss. This loss occurs without a person actively trying to diet or exercise, and it can be a result of the tumor’s impact on appetite or nutrient absorption.
When to Consult a Medical Professional
Noticing any changes in bowel function or systemic symptoms should prompt a consultation with a healthcare provider. Many conditions, such as hemorrhoids, irritable bowel syndrome, or dietary issues, can cause similar symptoms like bleeding, diarrhea, or abdominal discomfort. Self-diagnosing based on symptoms alone is inaccurate, and professional medical evaluation is the only way to determine the cause.
A doctor will typically take a detailed history of your symptoms, including how long they have persisted, and may order tests to investigate the underlying cause. If symptoms like persistent changes in bowel habits, unexplained fatigue, or visible blood in the stool last for more than a few weeks, an appointment should be scheduled without delay. The persistence of the symptom, rather than its severity, is what makes it a concern that requires professional attention.
In addition to investigating new or concerning symptoms, individuals should discuss colon cancer screening with their doctor, especially if they are 45 years of age or older. Screening procedures, like a colonoscopy, are designed to find and remove precancerous polyps before they can develop into cancer. If a person has a family history of the disease or other risk factors, their doctor may recommend starting the screening process at an earlier age.