Gastric carcinoma, commonly known as stomach cancer, is a malignancy that originates in the lining of the stomach. When these cancer cells spread from their initial site to other areas of the body, the condition is termed metastatic gastric carcinoma. This advanced stage of the disease presents significant challenges.
Understanding Metastasis in Gastric Carcinoma
Metastasis describes the process where cancer cells detach from the primary tumor and travel to distant parts of the body. In gastric carcinoma, these cells can spread through the bloodstream, lymphatic system, or by direct invasion into nearby organs. This spread differentiates metastatic gastric carcinoma from localized stomach cancer, where the tumor remains confined to the stomach.
The most common sites for gastric carcinoma to metastasize include the liver, peritoneum (the lining of the abdominal cavity), lungs, and bones. The liver is a frequent destination due to the stomach’s blood supply draining into it. The lymphatic system also serves as a pathway for cancer cells to spread. Diffuse-type gastric adenocarcinoma shows a higher tendency to spread to the peritoneum and bones compared to the intestinal type, which more frequently metastasizes to the liver.
Recognizing Signs and Diagnosis
Signs and symptoms of metastatic gastric carcinoma often differ from those of early-stage stomach cancer, as they are influenced by where the cancer has spread. Patients may experience unexplained weight loss, persistent nausea, and vomiting. Abdominal pain is also common, sometimes accompanied by bloating or a feeling of fullness after eating a small amount.
If the cancer has spread to the liver, symptoms can include pain on the right side of the abdomen, jaundice (yellowing of the skin and eyes), and itchy skin. Spread to the peritoneum may cause fluid buildup in the abdomen, known as ascites, leading to swelling and discomfort. Bone pain can signal metastasis to the bones, while lung involvement might result in shortness of breath or a persistent cough.
The diagnostic process begins with a physical examination, where a doctor may feel for any unusual masses or swelling. Blood tests are often performed, including a complete blood count to check for anemia, which can indicate bleeding in the stomach. Imaging tests are then used to assess the extent of the disease. These include CT scans of the chest, abdomen, and pelvis to identify areas of spread, such as enlarged lymph nodes or liver metastases. PET scans, which use a radioactive glucose tracer, can also help identify areas where cancer cells are highly active.
To confirm metastasis and determine the specific type of cancer cells, a biopsy is performed. This usually involves an upper endoscopy, where a thin, lighted tube with a camera is inserted through the mouth to view the esophagus, stomach, and duodenum, allowing for tissue samples. Laparoscopic biopsy, involving a small incision in the abdomen, can detect spread to the liver or peritoneum. Endoscopic ultrasound provides assessment of tumor invasion depth and local lymph node involvement.
Treatment Approaches
Treating metastatic gastric carcinoma involves systemic therapies, which are the mainstay of treatment, addressing cancer cells throughout the body. Chemotherapy, often involving combinations of drugs like fluoropyrimidine and platinum compounds, is a common first-line approach. These regimens prolong survival and enhance quality of life.
Targeted therapies focus on specific vulnerabilities within cancer cells. For example, trastuzumab, an anti-HER2 antibody, is used for patients whose tumors overexpress the HER2 protein. When combined with chemotherapy, trastuzumab has improved outcomes for individuals with HER2-positive metastatic gastric or gastroesophageal junction adenocarcinoma. Other targeted agents, such as ramucirumab, inhibit new blood vessel formation that tumors need to grow.
Immunotherapy, including checkpoint inhibitors, helps the body’s immune system recognize and attack cancer cells. This approach is increasingly used, often in combination with chemotherapy, particularly for advanced cancers that express specific biomarkers. Radiation therapy is used for symptom palliation, such as to relieve pain or bleeding. Surgery may be considered in selected cases to manage complications like blockages or bleeding, but it is not a primary treatment for widespread metastatic disease.
Prognosis and Supportive Care
The outlook for individuals with metastatic gastric carcinoma varies significantly, influenced by factors such as the extent of cancer spread, a person’s overall health, and how well they respond to treatment. While a cure is generally not possible at this advanced stage, treatments aim to manage the disease and its symptoms. For instance, the 5-year relative survival rate for metastatic stomach cancer is approximately 7%.
Supportive care, also known as palliative care, is an integral part of managing metastatic gastric carcinoma. This specialized medical care focuses on alleviating symptoms, improving quality of life, and providing comprehensive support for patients and their families. It addresses physical symptoms like pain, nausea, and fatigue, as well as emotional and psychological needs. A multidisciplinary team collaborates to provide coordinated and holistic care.