Carcinoma of the stomach, also known as Gastric Cancer, is a type of cancer that originates from the lining of the stomach. It is one of the leading causes of cancer-related deaths worldwide, though its incidence has decreased in some regions due to changes in diet and improved food preservation methods.
Key Points About Gastric Cancer:
- Types:
Adenocarcinoma: The most common type, accounting for over 90% of stomach cancers.
Lymphoma: Cancer of the immune system tissue found in the stomach wall.
Gastrointestinal stromal tumors (GISTs)*: Arising from the interstitial cells of Cajal in the stomach wall.
Neuroendocrine Tumors : Also called carcinoid tumors.
- Risk Factors:
Helicobacter pylori infection: Chronic infection with this bacterium is a major risk factor.
Diet : High salt, smoked foods, and pickled vegetables may increase risk, while fresh fruits and vegetables may lower it.
Genetics: Family history of gastric cancer, certain inherited syndromes.
Tobacco and alcohol use: Both are linked to an increased risk.
Previous stomach surgery: Surgery for benign conditions increases the risk over time.
- Symptoms:
Early stages may be asymptomatic or show non-specific symptoms like indigestion or mild discomfort.
Advanced stages can present with symptoms like unexplained weight loss, persistent stomach pain, nausea, vomiting (possibly with blood), difficulty swallowing, and blood in the stool.
- Diagnosis:
Endoscopy: Visualization and biopsy of suspicious areas.
Imaging: CT scans, PET scans, and sometimes barium swallow X-rays.
Biopsy: Histological examination of tissue to confirm the type of cancer.
- Treatment:
Surgery: Partial or total gastrectomy (removal of part or all of the stomach).
Chemotherapy: Often used before or after surgery or for advanced cases.
Radiation therapy: Used in combination with chemotherapy or for palliative care.
Targeted therapy: For tumors expressing specific markers, like HER2.
- Prognosis:
The prognosis depends heavily on the stage at diagnosis. Early-stage cancers have a much better prognosis compared to advanced stages, where the cancer has spread beyond the stomach.
- Prevention:
Lifestyle modifications: Diet rich in fruits and vegetables, avoiding excessive salt and smoked foods, and quitting smoking.
Screening: In some high-risk populations (like in Japan), screening programs using endoscopy are implemented to catch the disease early.
Gastric cancer, especially in its early stages, often presents with vague and non-specific symptoms. As the disease progresses, symptoms may become more pronounced. Here’s a list of common symptoms associated with gastric cancer:
Early Symptoms:
Indigestion or heartburn: Persistent discomfort or a burning sensation in the stomach area.
Mild discomfort in the abdomen: Often mistaken for minor digestive issues.
Feeling of fullness: Early satiety, or feeling full after eating a small amount of food.
Nausea and vomiting: Occasionally, this may include vomiting blood (hematemesis).
Loss of appetite: An unexplained lack of interest in eating.
Advanced Symptoms:
Unintentional weight loss: Significant and unexplained loss of weight.
Persistent stomach pain: Pain or discomfort in the upper abdomen that doesn’t go away.
Difficulty swallowing (dysphagia): A feeling of food getting stuck in the throat or chest, especially with tumors near the junction of the stomach and esophagus.
Vomiting blood: This can occur if the tumor causes bleeding in the stomach.
Blood in stool: Stools may appear black and tarry due to digested blood.
Fatigue: Persistent tiredness or weakness, often due to anemia caused by chronic blood loss.
Swelling or fluid build-up: Particularly in the abdomen (ascites) or in the legs.
Other Possible Symptoms:
Jaundice: Yellowing of the skin and eyes, if the cancer spreads to the liver.
Enlarged lymph nodes: Particularly in the neck or around the navel area.
Anemia: A decrease in red blood cells, leading to pale skin, fatigue, and shortness of breath.
It’s important to note that many of these symptoms can be caused by conditions other than gastric cancer, so they should be evaluated by a healthcare professional for accurate diagnosis. Early detection is crucial for improving the chances of successful treatment.
The diagnosis of gastric cancer involves a combination of clinical evaluation, imaging studies, endoscopic procedures, and laboratory tests. The process typically follows these steps:
- Clinical Evaluation
Medical History and Physical Examination: The physician will review the patient’s symptoms, family history, and risk factors (like Helicobacter pylori infection, diet, and smoking). A physical examination may reveal signs such as abdominal tenderness or an enlarged liver.
- Endoscopic Procedures
Upper Endoscopy (Esophagogastroduodenoscopy, EGD): This is the primary diagnostic tool for gastric cancer. A thin, flexible tube with a camera (endoscope) is inserted through the mouth to visualize the stomach lining. Any suspicious areas can be biopsied during this procedure.
Endoscopic Ultrasound (EUS): This technique combines endoscopy and ultrasound to obtain detailed images of the stomach wall and nearby lymph nodes. It helps assess the depth of tumor invasion and involvement of surrounding tissues.
- Imaging Studies
Computed Tomography (CT) Scan: A CT scan of the abdomen and pelvis helps determine the extent of the tumor, including possible spread to nearby organs or lymph nodes. It can also detect distant metastases.
Positron Emission Tomography (PET) Scan: Often combined with CT (PET-CT), this imaging modality helps identify cancerous tissue throughout the body by detecting areas of increased metabolic activity.
Magnetic Resonance Imaging (MRI): MRI is sometimes used to get detailed images, particularly when assessing liver metastases or in cases where a CT scan is inconclusive.
Barium Swallow X-ray: In some cases, a patient may undergo a barium swallow, where they drink a barium solution before undergoing X-rays to outline the stomach on imaging. This method is less commonly used due to advances in endoscopy and cross-sectional imaging.
- Biopsy and Histological Examination
Biopsy: Tissue samples taken during endoscopy are examined under a microscope by a pathologist to confirm the presence of cancer cells. The type and grade of the cancer are also determined through this analysis.
Molecular Testing: Tumor tissue may be tested for specific markers, such as HER2 (Human Epidermal Growth Factor Receptor 2), which can influence treatment decisions, particularly for targeted therapies.
- Laboratory Tests
Complete Blood Count (CBC): To check for anemia, which might result from chronic blood loss due to the tumor.
Liver Function Tests (LFTs): To assess whether the cancer has spread to the liver.
Tumor Markers: Blood tests like CEA (Carcinoembryonic Antigen) and CA 19-9 might be elevated in gastric cancer, though they are not specific and are usually used to monitor treatment response rather than for diagnosis.
- Staging
Staging Laparoscopy: In some cases, especially when considering surgery, a minimally invasive surgery called laparoscopy is performed to visualize the abdominal cavity and assess the extent of the disease. It helps to detect small metastases that might not be visible on imaging.
- Staging and Grading
TNM Staging System: The cancer is staged using the TNM system (Tumor size, Node involvement, Metastasis), which helps in determining the prognosis and guiding treatment.
The treatment of gastric cancer depends on several factors, including the stage of the cancer, its location, the patient’s overall health, and whether the cancer has spread to other parts of the body. The main treatment options include surgery, chemotherapy, radiation therapy, and targeted therapy, often used in combination. Here’s an overview of each approach:
- Surgery
Surgery is often the primary treatment for gastric cancer, especially if it is detected at an early stage. The goal is to remove the cancerous tissue along with some surrounding healthy tissue to ensure clear margins.
Subtotal Gastrectomy: This procedure involves removing the part of the stomach that contains the cancer. It’s typically performed when the tumor is located in the lower part of the stomach.
Total Gastrectomy: The entire stomach is removed, usually when the cancer is located in the upper part of the stomach or has spread throughout the stomach. The esophagus is then connected directly to the small intestine.
Lymph Node Dissection: Along with the stomach, nearby lymph nodes are often removed to check for the spread of cancer cells.
Palliative Surgery: In cases where the cancer is too advanced to be completely removed, surgery may still be performed to relieve symptoms like obstruction or bleeding, improving the patient’s quality of life.
- Chemotherapy
Chemotherapy uses drugs to kill cancer cells. It can be administered before surgery (neoadjuvant chemotherapy) to shrink the tumor, making it easier to remove, or after surgery (adjuvant chemotherapy) to kill any remaining cancer cells.
Systemic Chemotherapy: Drugs are given orally or intravenously, traveling through the bloodstream to reach cancer cells throughout the body.
Intraperitoneal Chemotherapy: In certain cases, chemotherapy drugs may be delivered directly into the abdominal cavity.
Common chemotherapy drugs used for gastric cancer include fluorouracil (5-FU), cisplatin, oxaliplatin, capecitabine, and epirubicin, often used in combination.
- Radiation Therapy
Radiation therapy uses high-energy rays to kill cancer cells or shrink tumors. It’s often combined with chemotherapy (chemoradiation) and may be used before surgery to shrink the tumor or after surgery to eliminate residual cancer cells.
External Beam Radiation Therapy (EBRT): The most common form, where radiation is directed at the cancer from outside the body.
Palliative Radiation: Used to relieve symptoms such as pain, bleeding, or obstruction caused by advanced cancer.
- Targeted Therapy
Targeted therapy involves drugs that specifically target certain molecules involved in cancer growth and survival. These therapies are often used in combination with chemotherapy for advanced or metastatic gastric cancer.
HER2-targeted Therapy: For tumors that overexpress the HER2 protein, drugs like trastuzumab (Herceptin) are used.
VEGF-targeted Therapy: Ramucirumab (Cyramza) targets the vascular endothelial growth factor (VEGF) receptor, which plays a role in tumor blood vessel growth.
Immunotherapy: For certain advanced gastric cancers, immunotherapy drugs like pembrolizumab (Keytruda) may be used, especially in tumors with high microsatellite instability (MSI) or PD-L1 expression.
- Immunotherapy
Immunotherapy leverages the body’s immune system to fight cancer. While it’s not a first-line treatment for gastric cancer, it may be used for advanced cases that have specific biomarkers.
Immune Checkpoint Inhibitors: Drugs like pembrolizumab target PD-1/PD-L1 pathways, helping the immune system recognize and attack cancer cells.
- Nutritional Support
Gastric cancer and its treatments can significantly impact nutrition. Patients often require dietary modifications, and in some cases, enteral (tube feeding) or parenteral (intravenous) nutrition may be necessary to maintain adequate nutrition.
- Palliative Care
For advanced gastric cancer, the focus may shift to palliative care, which aims to relieve symptoms and improve quality of life rather than cure the disease. Palliative care can include pain management, nutritional support, and psychological support.
- Clinical Trials
Patients with gastric cancer may consider participating in clinical trials, which offer access to new treatments that are not yet widely available. These trials help to improve the understanding of the disease and potentially offer better treatment options.
Multidisciplinary Approach
Treatment of gastric cancer typically involves a multidisciplinary team, including surgeons, medical oncologists, radiation oncologists, gastroenterologists, dietitians, and other healthcare professionals, to provide comprehensive care tailored to the patient’s needs.
The treatment plan is personalized for each patient, taking into account the stage of the cancer, the patient’s overall health, and their preferences. Early-stage cancers have a better prognosis and are more likely to be curable with surgery alone, while advanced-stage cancers often require a combination of treatments to manage the disease.