Ascites is the medical term for an abnormal buildup of fluid within the abdomen’s peritoneal cavity. The lining of this cavity, the peritoneum, normally produces a small amount of fluid that acts as a lubricant for internal organs. When the systems that regulate this fluid are disrupted, excess fluid can accumulate, leading to swelling and pressure. While ascites is commonly associated with conditions like liver disease, it can also be a significant indicator of ovarian cancer, as the fluid may contain cancer cells and proteins.
The Link Between Ovarian Cancer and Ascites
Ascites develops with ovarian cancer as a direct result of the cancer’s activity. One cause is the irritation of the peritoneum. When ovarian cancer cells spread, they can implant on this lining, causing inflammation. This irritation makes the peritoneal membrane more permeable, allowing fluid from blood vessels to seep into the abdominal cavity.
Disruption of the lymphatic system is another factor. This network of vessels drains excess fluid from tissues and returns it to the bloodstream. Ovarian cancer tumors can physically block or damage these lymphatic channels, impairing their drainage function. The result is a backlog of fluid that collects in the peritoneal space.
Cancer cells also promote fluid accumulation by releasing specific proteins like Vascular Endothelial Growth Factor (VEGF). This substance stimulates the formation of new blood vessels that tumors use for growth. A side effect of VEGF is that it makes existing blood vessels more “leaky,” causing plasma to escape into the abdominal cavity.
Recognizing and Diagnosing Ascites
The symptoms of ascites often develop gradually. The most prominent sign is a noticeable swelling or bloating of the abdomen that does not resolve, sometimes with rapid weight gain. As the fluid volume increases, it can exert pressure on surrounding organs, leading to shortness of breath, a persistent feeling of fullness, abdominal pain, and nausea.
A physician may begin with a physical examination. They may tap on the abdomen (percussion) to listen for the dull sound of fluid. Another technique involves checking for a “fluid wave,” where tapping one side of the abdomen causes a ripple felt on the opposite side.
To confirm the presence of fluid, doctors rely on imaging scans. An ultrasound is frequently used to visualize fluid accumulation. For a more detailed view of the abdominal cavity and to assess the cancer, a computed tomography (CT) or magnetic resonance imaging (MRI) scan may be ordered.
A definitive diagnostic step is a procedure called paracentesis. During this procedure, a thin needle is inserted through the abdomen to draw out a sample of the ascitic fluid. This fluid is then sent to a laboratory for analysis, known as cytology, to check for the presence of cancer cells. If found, the condition is confirmed as malignant ascites.
Impact on Cancer Staging and Prognosis
The presence of malignant ascites is a factor in determining the stage of ovarian cancer. According to the FIGO staging system, finding cancer cells in the abdominal fluid automatically classifies the cancer as at least Stage IC. This means the cancer is no longer confined entirely within the ovary and has spread into the abdominal cavity.
This classification directly impacts the treatment plan. A Stage IC diagnosis necessitates more comprehensive treatment following surgery, often involving chemotherapy to target cancer cells that have moved into the abdomen. The presence of ascites signals that the cancer can shed cells that can survive and circulate within the peritoneal cavity.
Beyond the initial staging, the volume of ascites and how it responds to treatment can serve as an indicator of prognosis. A large volume of fluid at diagnosis is associated with more advanced disease. If ascites develops or worsens during or after chemotherapy, it may suggest the cancer is not responding effectively.
The fluid itself is more than just a byproduct; it can create an environment that promotes further cancer growth. Ascitic fluid contains nutrients and growth factors that can nourish cancer cells and facilitate their spread. This is why managing ascites is an important part of the overall cancer treatment strategy.
Managing and Treating Ascites
Managing ascites involves relieving symptoms while also addressing the underlying cancer. The most direct method for alleviating pressure is a therapeutic paracentesis. This procedure involves draining large volumes of fluid from the abdomen, which can provide temporary relief from symptoms like pain and shortness of breath.
Diuretics, or “water pills,” may be prescribed to help the body eliminate excess fluid. These drugs often have limited success in managing ascites caused by cancer because the primary issue is fluid leakage, not overall fluid retention. Their effectiveness depends on the specific mechanisms causing the fluid accumulation.
When fluid builds up quickly and requires frequent drainage, an indwelling catheter may be offered. This thin, flexible tube is surgically placed into the abdomen, allowing the patient or a caregiver to drain fluid regularly at home. This approach avoids repeated trips to the hospital and gives the patient more control over their symptoms.
Ultimately, the most effective long-term strategy for controlling ascites is to treat the ovarian cancer itself. Systemic treatments like chemotherapy are designed to shrink or destroy cancer cells, leading to a natural reduction in ascites. Newer targeted therapies, including PARP inhibitors and anti-angiogenesis drugs like bevacizumab, can also be effective by disrupting the biological processes that allow the cancer to produce fluid.