An Introduction to Stomach Cancer Treatment
Stomach cancer, also known as gastric cancer, requires a carefully planned and individualized treatment strategy. The approach is determined by a number of critical factors, chief among them being the stage of the cancer—which includes its size, depth of invasion into the stomach wall, and whether it has spread to lymph nodes or distant organs. Other important considerations are the tumor’s specific location within the stomach, its molecular characteristics (such as HER2 status), and the patient’s overall health and fitness for treatment.
The goals of treatment vary based on the stage. For early-stage disease, the goal is curative, aiming to completely remove the cancer and prevent its recurrence. For more advanced or metastatic cancer, the focus shifts to palliative care, with the goals of slowing the cancer’s progression, relieving symptoms, and maintaining the best possible quality of life.
The Role of the Multidisciplinary Team (MDT)
The complexity of stomach cancer necessitates a collaborative approach from a multidisciplinary team (MDT). This group of specialists from different medical fields works together to review diagnostic information, develop a comprehensive treatment plan, and coordinate care. This team-based strategy is the standard of care and ensures that patients receive a holistic and well-rounded treatment recommendation.
A typical stomach cancer MDT includes:
- Gastroenterologist: A specialist who often diagnoses the cancer via an upper endoscopy and biopsy.
- Surgical Oncologist: A surgeon with expertise in operating on the stomach and surrounding organs.
- Medical Oncologist: A physician who treats cancer with systemic medications like chemotherapy, targeted therapy, and immunotherapy.
- Radiation Oncologist: A doctor who specializes in using radiation therapy to treat cancer.
- Pathologist: A physician who examines the tumor tissue to determine its exact type, grade, and molecular features.
- Radiologist: A physician who interprets imaging studies (such as CT and PET scans) to determine the cancer’s stage.
- Dietitian/Nutritionist: A professional who provides critical support to manage nutritional challenges before and after treatment.
Treatment for Very Early-Stage Stomach Cancer
For very small, superficial cancers that are confined to the innermost layer of the stomach lining (the mucosa), it is sometimes possible to avoid major surgery. Highly specialized, minimally invasive procedures can be performed during an upper endoscopy.
- Endoscopic Mucosal Resection (EMR): The gastroenterologist injects a solution under the small tumor to lift it, then removes it with a snare passed through the endoscope.
- Endoscopic Submucosal Dissection (ESD): For slightly larger or flatter early-stage tumors, this more advanced technique allows the physician to dissect and remove the cancerous tissue in one single piece.
These endoscopic procedures are only suitable for a select group of patients with very early-stage disease, as determined by detailed imaging and evaluation.
Surgical Treatment for Stomach Cancer
For most patients with resectable stomach cancer (Stages I, II, and III), surgery is the cornerstone of curative treatment. The primary goal of surgery is to remove the entire tumor along with a margin of healthy tissue and nearby lymph nodes. The type of surgery depends on the tumor’s location.
- Subtotal (or Partial) Gastrectomy: If the cancer is located in the lower portion of the stomach, the surgeon removes that part of the stomach. The remaining upper portion is then reconnected directly to the small intestine.
- Total Gastrectomy: If the cancer is in the upper part of the stomach or is widespread, the entire stomach must be removed. In this procedure, the surgeon connects the esophagus directly to the small intestine, creating a new path for food to travel.
Lymph Node Dissection
A critical part of the surgery is the removal of nearby lymph nodes (a lymphadenectomy). The pathologist examines these nodes for cancer cells, which is essential for accurately staging the disease. A D2 lymphadenectomy, which involves removing a more extensive set of lymph nodes, is the standard of care in many centers as it provides the most accurate staging and may improve outcomes.
The Role of Systemic Therapies
Systemic therapies are drug treatments that circulate through the bloodstream to kill cancer cells throughout the body. They are a vital component of treatment for many stages of stomach cancer.
Chemotherapy
Chemotherapy can be used at different points in the treatment journey:
- Perioperative or Neoadjuvant Chemotherapy: This refers to chemotherapy given before surgery. The goals are to shrink the tumor to make it easier to remove completely, and to attack any microscopic cancer cells that may have already spread. Often, it is given both before and after surgery.
- Adjuvant Chemotherapy: This is chemotherapy given after surgery to destroy any remaining cancer cells and reduce the risk of the cancer returning. It is often given in combination with radiation (chemoradiation).
- Palliative Chemotherapy: For advanced or metastatic (Stage IV) cancer, chemotherapy is the primary treatment used to shrink tumors, control symptoms, and help prolong life.
Targeted Therapy
Targeted therapies are drugs designed to attack specific vulnerabilities in cancer cells. For stomach cancer, the most important target is a protein called HER2. About 20% of stomach cancers produce too much of this protein, which helps them grow. These cancers are called “HER2-positive.” If a tumor is found to be HER2-positive, a targeted drug that blocks the HER2 protein can be added to chemotherapy, which can significantly improve its effectiveness.
Immunotherapy
Immunotherapy is a class of drugs that helps a patient’s own immune system recognize and fight cancer. These drugs, known as checkpoint inhibitors, have become an important option for some patients with advanced stomach cancer, particularly those whose tumors express a protein called PD-L1 or have a specific genetic feature known as high microsatellite instability (MSI-H).
The Role of Radiation Therapy
Radiation therapy uses high-energy beams to destroy cancer cells. Its role in stomach cancer is almost always in combination with chemotherapy (a treatment known as chemoradiation). The chemotherapy makes the cancer cells more sensitive to the effects of the radiation.
- As an Adjuvant Treatment: Chemoradiation is often given after surgery to reduce the risk of the cancer recurring in the stomach bed or nearby lymph nodes.
- As a Neoadjuvant Treatment: It can be used before surgery, particularly for tumors located at the junction between the esophagus and the stomach, to help shrink the tumor.
- As a Palliative Treatment: For advanced cancer, radiation can be very effective at relieving symptoms, such as pain or bleeding from a tumor.
Nutritional and Supportive Care
Nutritional support is a vital part of stomach cancer treatment. The cancer itself can cause poor appetite and weight loss. Furthermore, after a gastrectomy, the way the body processes food is permanently altered. Patients will need to eat smaller, more frequent meals. A dietitian works closely with the patient both before and after surgery to manage their nutritional needs, prevent “dumping syndrome,” and ensure they can maintain their weight and strength. In some cases, a temporary feeding tube may be placed during surgery to provide nutrition while the body heals.
Frequently Asked Questions
1. What is the difference between a subtotal and a total gastrectomy?
A subtotal gastrectomy involves removing only a part of the stomach, usually the lower portion where the tumor is located. A total gastrectomy is the removal of the entire stomach, which is necessary if the cancer is in the upper part or affects a large area. In both cases, the surgeon reconnects the digestive tract to allow for the passage of food.
2. Why is chemotherapy often given before stomach cancer surgery?
Chemotherapy given before surgery (neoadjuvant or perioperative chemotherapy) has two main goals. First, it aims to shrink the primary tumor, which may increase the likelihood that the surgeon can remove it completely with clear margins. Second, it treats any microscopic cancer cells that may have already spread but are not visible on scans, reducing the risk of a future recurrence.
3. What does it mean if a stomach cancer is “HER2-positive”?
HER2 is a protein that can be found on the surface of some cancer cells, where it acts like an “on” switch, telling the cells to grow and divide. If a stomach tumor has an abnormally high amount of this protein, it is called HER2-positive. This is an important finding because there are specific targeted therapy drugs that can block the HER2 protein, providing a more effective treatment when added to standard chemotherapy.
4. Why are lymph nodes removed during stomach cancer surgery?
Removing and examining the lymph nodes near the stomach is a critical part of the operation. It allows the pathologist to determine if the cancer has spread beyond the stomach, which is the most important factor in “staging” the cancer accurately. This staging information is essential for deciding whether a patient needs additional treatment, like chemotherapy or chemoradiation, after surgery.
5. Can stomach cancer be treated without major surgery?
Only in very specific and rare circumstances. If a cancer is detected at a very early stage, when it is still confined to the innermost lining (mucosa) of the stomach, it can sometimes be completely removed through an endoscope. These procedures, called EMR or ESD, are minimally invasive but are only an option for a small fraction of patients.
6. What is dumping syndrome?
Dumping syndrome is a potential side effect after stomach surgery where food, especially sugar, moves from the newly reconnected esophagus or remaining stomach pouch into the small intestine too quickly. This can cause symptoms like cramping, nausea, dizziness, and diarrhea shortly after eating. It is often managed with dietary changes, such as eating smaller, more frequent, low-sugar meals.
7. Is radiation therapy always used for stomach cancer?
No. The use of radiation therapy depends on the cancer’s stage and location, as well as the treatment approach being used. It is most often used in combination with chemotherapy (chemoradiation) after surgery to reduce the risk of local recurrence. It may also be used before surgery for tumors at the gastroesophageal junction. It is not used for all patients.
