Constipation is the most common gastrointestinal complaint in the United States, affecting more than 4 million Americans and accounting for more than two million visits to the doctor each year.  While the groups most often affected are women and adults over age 65, constipation is also a significant problem for people with cancer. Contributing factors include dietary and activity patterns, anatomic considerations, pain medication, and a number of cancer treatments.

Though most constipation is temporary and often perceived as a mere nuisance, persistent difficulty with bowel movements can lead to long term complications, and there are rare cases of constipation leading to serious illness and death. Given the potential negative effects on health, it is important to recognize the factors contributing to constipation and to practice effective management and prevention tactics.

Bowel motility is the complex function of the intestine maintaining water balance in the stool, propelling feces toward the exit, and signaling an individual to recognize when a bowel movement is necessary. People with cancer experience reduced bowel motility for a number of reasons. Nausea or swallowing difficulty may lead to reduced intake of water and fiber, two key dietary components in maintaining healthy bowel habits. Also, physical activity stimulates bowel motility, and reduced movement due to pain or fatigue can often lead to constipation.

Metabolic abnormalities, such as high calcium (common in patients with lung cancer, breast cancer and multiple myeloma) can also lead to reduced bowel motility and constipation, as can a number of pain medications, particularly opioids such as morphine and fentanyl.  For certain cancer patients, abdominal and pelvic tumors and scar tissue from prior surgeries can act as anatomic barriers to normal stool passage.

Finally, spinal cord or nerve damage from tumors or chemotherapeutic agents can disrupt neural signals to the colon, rectum, and anus; the result is a condition termed "neurogenic bowel dysfunction," consisting of reduced bowel motility and difficulty emptying the rectum.

While it is important to recognize and address the presence of constipation, the condition is often viewed as an annoyance rather than a medical problem. But impaired bowel function can lead to a number of physical complications, including fecal incontinence, ulceration and damage to rectal tissue, and the development of numerous out-pouchings along the colon known as diverticulosis.

In rare cases, constipation can lead to potentially life-threatening conditions such as fecal impaction (the accumulation of dry, hard feces in the rectum that often cannot be expelled without assistance), and volvulus (twisting of the bowel that can result in serious and permanent damage of the intestine). Treatment and prevention can help avoid these serious complications, while also reducing social and physical discomfort associated with constipation.