Omentum cancer affects the omentum, a layer of fatty tissue in the abdomen that covers organs like the stomach and intestines. While cancer originating in this tissue is extremely rare, the term “omentum cancer” more commonly refers to cancer that has metastasized from a primary tumor in another organ. Because the omentum is a common site for cancer cells to settle and grow, its involvement is often linked to the progression of other cancers.
The Omentum’s Role in the Body
The omentum is a large, apron-like fold of visceral peritoneum that hangs from the stomach and drapes over the intestines. It is composed of a double layer of fatty tissue and contains an extensive network of blood and lymphatic vessels. This structure is divided into two parts: the greater omentum, which attaches to the stomach and transverse colon, and the lesser omentum, which connects the stomach and duodenum to the liver.
The omentum serves several purposes. It acts as a storage site for adipose (fat) tissue, providing insulation and an energy reserve. It also plays a protective role by physically cushioning the abdominal organs from injury. The omentum is highly mobile and can move to wall off inflamed areas, preventing the spread of infection to the rest of the abdominal cavity. It also contains collections of immune cells that help manage inflammation and remove cellular debris.
Omental Cancer as a Secondary Disease
The omentum’s biological environment makes it a frequent site for metastatic disease. Its rich supply of blood and lymphatic vessels provides a direct route for cancer cells that have broken away from a primary tumor to travel and implant themselves within its tissue.
Once lodged in the omentum, cancer cells find a hospitable environment for growth. The fatty tissue of the omentum contains energy-rich cells that can fuel the rapid multiplication of these malignant cells. Additionally, the omentum possesses stem cells that promote the formation of new blood vessels, a process called angiogenesis, which tumors exploit to create their own blood supply.
The most frequent primary cancers that spread to the omentum originate in the abdominal and pelvic regions. In women, ovarian cancer is the most common source of omental metastases. For men, cancers of the gastrointestinal tract, including the stomach, colon, and pancreas, are the most typical primary sources. Cancer can spread through direct extension from a nearby tumor or via shedding cancer cells into the peritoneal fluid.
Symptoms and Diagnostic Process
The symptoms of omental cancer are often nonspecific and subtle, which can delay diagnosis. Many individuals may not experience any symptoms in the early stages. When symptoms do appear, they commonly include:
- Abdominal bloating or visible swelling, caused by fluid accumulation (ascites)
- Persistent abdominal pain or a feeling of pressure
- A sensation of fullness after eating only a small amount (early satiety)
- Unexplained weight loss
- Changes in bowel habits, nausea, and vomiting
The diagnostic process begins with a physical examination and a review of medical history. To visualize the abdominal cavity, doctors use imaging tests like a computed tomography (CT) scan. A CT scan can reveal “omental caking,” where the omental tissue becomes thickened with tumor deposits. Magnetic resonance imaging (MRI) and ultrasound may also be employed.
Blood tests may be ordered to check for tumor markers, such as CA-125 in suspected ovarian cancer. However, a definitive diagnosis requires a biopsy, where a small sample of omental tissue is surgically removed and examined. This analysis confirms the presence of cancer cells and helps determine their primary origin, which is necessary for planning treatment.
Treatment Approaches
The treatment for omental cancer focuses on addressing both the metastatic disease in the omentum and the primary cancer from which it spread. The strategy is often multimodal, combining surgery with systemic therapies. The specific plan is tailored to the type and stage of the primary cancer, the extent of the omental involvement, and the patient’s overall health.
A primary surgical intervention is an omentectomy, the surgical removal of the omentum. This procedure is often part of a larger cytoreductive or “debulking” surgery, where the goal is to remove as much visible tumor as possible from the abdominal cavity. A complete omentectomy is recommended because it removes a major site of disease and eliminates a tissue environment favorable for tumor growth.
Systemic treatments like chemotherapy are used to target cancer cells throughout the body, either following surgery or sometimes before. In some cases, an advanced technique called Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is used. With HIPEC, a heated chemotherapy solution is circulated directly within the abdominal cavity immediately after cytoreductive surgery.
The heat is believed to enhance the effectiveness of the chemotherapy drugs, allowing for a higher concentration of medicine to reach any remaining cancer cells. Other treatments may include targeted therapy and immunotherapy, which are emerging as options for certain types of cancer.
Managing Omental Metastases and Prognosis
The long-term outlook for a patient with omental metastases is heavily influenced by the characteristics of the primary cancer. Factors such as the cancer’s origin, its stage at diagnosis, and its biological properties are more significant in determining prognosis than the presence of omental disease alone. Management strategies are therefore designed to control the primary tumor while alleviating complications from the metastasis.
A significant challenge in managing omental metastases is the control of ascites, the painful buildup of fluid in the abdomen. Palliative procedures like paracentesis are used to manage this symptom and improve a patient’s quality of life. During paracentesis, a needle is inserted into the abdomen to drain the excess fluid, which can provide temporary relief.
Ongoing care involves regular monitoring to track the disease’s progression and treatment effectiveness. While surgical resection of the omentum may improve survival in some cases, the overall prognosis remains tied to the underlying malignancy. Supportive care is a part of the management plan, focusing on symptom relief, nutritional support, and psychological well-being.