Chemotherapy-induced diarrhea in colorectal cancer: causes and current treatments

The authors discussed the causes of diarrhea and current treatment options for colorectal cancer patients with diarrhea.

Colorectal cancer is a very common cancer worldwide. Improvements in screening and medication over the past 20 years have improved diagnosis, patient outcome and survival. However, some of these improvements are linked with increased side effects. Diarrhea is a common and often severe side effect of treatments for colorectal cancer. Between 46% and 79% of colorectal cancer patients have diarrhea after chemotherapy. The diarrhea can be severe for between 4% and 47.5% of patients, depending on the combination of chemotherapy. Reducing the rate of diarrhea would improve patient care and quality of life during treatment.

In this article the authors discussed the causes of diarrhea and the current treatment options.

Causes

Chemotherapy can lead to activation of the immune system in the bowel. This immune activation leads to inflammation in the bowel and damage to the bowel tissue. Diarrhea usually occurs once this damage happens. Roughly two weeks after chemotherapy the bowel begins to heal itself.

Differences in how chemotherapy is given can reduce patients’ risk of having diarrhea. 21% to 30% of patients who received 5-fluorouracil (Efudex) as a single injection (bolus) had severe diarrhea compared to only 4% of patients who received 5-fluorouracil as a very slow injection (infusion).

Treatments

Loperamide (Imodium, Lopex) helps decrease diarrhea by decreasing the activity of the intestine. It is safe and affordable, and is commonly used as the first treatment option for diarrhea that is caused by chemotherapy. It is especially useful for treating mild or moderate diarrhea. For patients with severe diarrhea after 5-fluorouracil chemotherapy, only 52% of patients’ diarrhea improved with loperamide.

Octreotide (Sandostatin) slows down the activity of the small bowel and reduces the amount of fluid produced by the stomach, intestine and pancreas. This reduces the amount of fluid that the colon needs to absorb. Octreotide is better than loperamide at treating diarrhea caused by 5-fluorouracil-based chemotherapy.  It is prescribed, as injections under the skin (100 µg twice per day), to patients who do not improve with loperamide.

Anti-inflammatory drugs are being tested for treating diarrhea. Although some treatments (such as budesonide [Rhinocort] or celecoxib [Celebrex]) may be helpful, more research is needed to clarify this. 

The authors concluded that diarrhea is still a big problem for patients treated with standard chemotherapy. They also suggest that new treatments for diarrhea are needed to improve patients care. 

Diarrhea is a common and sometimes serious side effect of colorectal cancer treatment. If you have diarrhea please discuss treatment options with your doctor.