Colon cancer, which originates in the large intestine, is a serious medical condition that can cause a range of symptoms, including abdominal discomfort. While early stages often do not produce noticeable symptoms, persistent or fluctuating abdominal discomfort can be an indicator that something is wrong. If you experience changes in your digestive health that last for more than a few days, consult a medical professional, as a proper diagnosis is the only way to determine the cause of persistent symptoms.
The Intermittent Nature of Colon Pain
The pain associated with colon cancer frequently presents as an intermittent or on-again, off-again sensation, particularly in the early stages. This fluctuating pattern often causes patients to mistake the discomfort for less serious issues, such as gas pain or indigestion. The pain is typically described as a cramp-like feeling or a dull ache in the abdomen, sometimes referred to as colicky pain.
A partial obstruction of the bowel is a primary reason for this fluctuating pain pattern. When the tumor narrows the colon’s passage, the natural movement of stool and gas is impeded. The muscular wall of the colon works harder to push material past the blockage, causing a spasm or cramp that generates the pain. Once material moves past the tumor, the pressure briefly subsides, and the pain temporarily resolves, only to return when more material backs up.
Physical Causes of Colon Cancer Pain
The sensation of pain in colon cancer arises from several distinct physical mechanisms. The most common cause is the mechanical obstruction of the intestinal lumen by the growing tumor mass. As the tumor occupies space, the internal diameter of the colon shrinks, leading to a buildup of pressure from the accumulating intestinal contents. This pressure stretches the colon wall and triggers pain receptors. This stretching and the subsequent muscular contractions attempting to overcome the blockage are responsible for the cramping sensation.
Another mechanism involves the tumor’s mass effect, where its size stretches or presses against nearby organs and nerves. The colon itself has a relatively sparse nerve supply that registers pain. However, when the tumor grows large enough to involve surrounding tissues or the outer layer of the colon, the pain becomes more constant and localized. If the cancer spreads to the abdominal lining or other organs, it can cause more widespread discomfort.
Inflammation and ulceration of the tumor’s surface also contribute to the generation of pain signals. As the tumor grows, its surface can become irritated, inflamed, or even ulcerated and bleed, which irritates the sensitive lining of the colon. This irritation causes localized inflammation, which activates pain pathways. Tumors on the left side of the colon, where the stool is more solid, are more likely to cause noticeable obstruction and pain than those on the right, where the contents are more liquid.
Non-Pain Symptoms Requiring Immediate Attention
While pain is a significant symptom, several other physical changes often accompany or precede colon cancer discomfort and warrant prompt medical evaluation.
- Persistent changes in bowel habits, including a lasting bout of diarrhea, constipation, or an unexplained alternation between the two.
- The presence of blood in the stool, which may appear bright red or cause the stool to look dark and tarry. Chronic, low-level blood loss can lead to persistent fatigue and weakness due to iron-deficiency anemia.
- Unintentional and unexplained weight loss, which occurs because cancer cells consume the body’s energy or the tumor interferes with nutrient absorption.
- A feeling of incomplete bowel emptying, known as tenesmus.
- Stool becoming noticeably narrower or ribbon-like due to the constricted passage.
Strategies for Managing Discomfort
Managing the discomfort associated with colon cancer involves a multi-modal approach focused on relieving the symptom and addressing the underlying cause of the obstruction. For mild to moderate pain, healthcare providers often start with non-opioid medications, such as acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs). When pain is more severe, weak opioids like codeine or tramadol may be prescribed, sometimes in combination with non-opioid drugs.
Anti-spasmodic agents, such as hyoscine butylbromide, can be helpful in reducing the cramping and colicky pain by relaxing the smooth muscles of the bowel wall. Dietary adjustments are also frequently recommended, specifically a low-residue diet minimizing the amount of indigestible fiber that passes through the colon. This reduces the risk of a complete blockage and helps to reduce the pressure and mechanical irritation that contributes to the intermittent pain.
In cases where the tumor causes a significant or near-complete blockage, palliative interventions are necessary to relieve the obstruction and the associated severe pain. One common procedure is the placement of a self-expandable metal stent (SEMS) into the narrowed area to physically hold the colon open and allow the passage of waste. Surgical bypass or the creation of a temporary or permanent stoma may also be performed to divert the flow of waste around the obstruction, providing immediate and lasting relief from the symptoms of a blocked bowel.