Ovarian cancer often presents with vague symptoms, which can complicate early diagnosis. Digestive issues, including persistent diarrhea, are common complaints. This symptom is frequently overlooked because it mimics less serious conditions like irritable bowel syndrome or temporary stomach upset. Understanding why this gynecologic cancer affects the digestive system requires examining how the disease and its treatments interact with the abdominal environment.
Physical Pressure and Mass Effect
The female reproductive organs, including the ovaries, sit within the pelvis, close to the intestinal tract, specifically near the sigmoid colon, rectum, and small intestine. A growing ovarian tumor creates a physical mass that occupies this limited space within the abdominal and pelvic cavities. As the tumor enlarges, it exerts direct pressure on adjacent sections of the bowel.
This external compression impedes peristalsis, the normal wave-like contractions of the intestines. This mechanical blockage can slow waste movement, sometimes causing constipation. However, this disruption can also cause diarrhea, especially if the tumor causes a partial obstruction. In a partial obstruction, the intestine secretes excess fluid, and only liquid stool can pass around the blockage, which is perceived as diarrhea.
Direct Tumor Invasion of the Bowel
Beyond physical pressure, ovarian cancer frequently spreads through peritoneal carcinomatosis, a significant cause of digestive distress. This occurs when cancer cells shed from the primary tumor and implant on the peritoneum, the membrane lining the abdominal cavity. These implants can directly infiltrate the wall of the small or large intestine.
When cancer cells invade the bowel wall, they initiate a severe inflammatory response. This inflammation damages the mucosal lining, impairing the gut’s ability to absorb water and nutrients. This structural damage leads to malabsorption and increased water content in the stool. Furthermore, tumor or inflammatory cells release substances like cytokines that stimulate the intestinal lining to secrete fluids and electrolytes into the bowel lumen, causing secretory diarrhea.
Treatment-Related Digestive Distress
The medical interventions used to fight cancer are a major, separate source of digestive side effects. Chemotherapy drugs, such as platinum agents and taxanes, target and destroy rapidly dividing cells. Since the cells lining the gastrointestinal tract (the mucosa) divide quickly, they are inadvertently damaged by these treatments. This damage leads to mucositis, which is inflammation and ulceration of the digestive tract lining.
The destruction of mucosal cells impairs the gut’s barrier function and its capacity to absorb water, resulting in significant diarrhea. Diarrhea is common in patients receiving chemotherapy, with severity varying based on the specific drug regimen. Pelvic radiation therapy, often used in gynecologic cancers, also causes diarrhea by directly damaging the small and large bowel tissue within the radiation field. Radiation-induced damage causes inflammation and impaired absorption, an effect compounded when both treatments are given concurrently.
Beyond cytotoxic treatments, newer therapies like immunotherapy and targeted agents can disrupt normal gut function. Immune checkpoint inhibitors can cause immune-related colitis, where the immune system attacks the colon, leading to severe diarrhea. Antibiotics, often given to cancer patients, can disrupt the gut microbiome and lead to infectious causes of diarrhea, such as Clostridium difficile infection.
Managing and Mitigating Diarrhea
Managing diarrhea involves a multi-faceted approach focused on controlling symptoms and preventing dehydration. The first line of defense includes dietary adjustments, such as adopting a low-fiber, bland diet. Patients should avoid foods that irritate the gut or stimulate motility, including spicy foods, high-fat items, caffeine, and alcohol.
Aggressive fluid and electrolyte replacement is necessary to counteract losses from frequent, watery stools. Drinking clear liquids, broths, and sports drinks helps maintain hydration and replace essential minerals. Medical management utilizes anti-motility medications, such as loperamide, often prescribed in a specific dose regimen for cancer-related diarrhea. For severe cases, a physician may prescribe stronger agents or use anti-secretory drugs like octreotide. Consulting with the oncology team before initiating any medication is important, as self-medicating can mask serious underlying issues.