Stomach Cancer Treatment: A Complete Guide

When talking about staging stomach cancer, it’s important to know the five layers of tissue and muscle that make up the stomach wall:

• Mucosa, the innermost layer and the location where nearly all stomach cancers start
• Submucosa, a supporting layer directly under the mucosa
• Muscularis propria (muscle layer), a thick layer of muscle that moves and mixes the stomach contents
• Subserosa, a layer of connective tissue between the muscle layer and the serosa
• Serosa, the outer layer of the stomach that wraps around it

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The stages of gastric cancer are as follows:

• Stage 0 Also known as carcinoma in situ, stage 0 occurs when abnormal cells are growing in the mucosa, the innermost layer of your stomach wall. This is considered a “precancerous” condition rather than actual invasive cancer. These cells may become cancerous and spread to other normal tissue.
• Stage 1 The cancer has spread into deeper layers of the stomach lining, such as the submucosa or muscle layer, and possibly to one or two nearby lymph nodes.
• Stage 2 The cancer has spread to deeper layers (up to and maybe including the outer layer of the stomach) and more nearby lymph nodes, but it has not yet reached distant organs.
• Stage 3 The cancer has spread to all layers of the stomach wall and more extensively to nearby lymph nodes. It may have also spread to one or more nearby organs or to the back of the abdomen.
• Stage 4 The cancer has spread to distant parts of the body, such as the liver, lungs, distant lymph nodes, or tissue that lines the abdomen wall. Also known as metastatic stomach cancer, stage 4 stomach cancer develops when the cancer cells travel through the lymphatic or circulatory system and form tumors made up of stomach cancer cells (for instance, metastatic stomach cancer in the lungs are made of stomach cells, not lung cells).

Surgery is a standard treatment for stomach cancer, with the specific type of surgery depending on the cancer's location.

You may be treated with chemotherapy, sometimes combined with radiation (called chemoradiation), before surgery to make the cancer easier to remove and to preserve more healthy tissue. You may also receive chemotherapy, radiation, or both after surgery to kill any remaining cancer cells and reduce the risk of recurrence.

Curative Surgery for Stomach Cancer

• Endoscopic Resection For very early stage cancers, surgeons may guide an endoscope (a long, thin tube with a video camera at the end) through the mouth and throat into the stomach to remove the tumor.
• Subtotal (Partial) Gastrectomy This procedure involves removing part of the stomach, depending on the tumor's location, and reattaching the remaining section of the stomach. Your surgeon may also remove nearby lymph nodes and parts of other nearby organs that may be affected, such as the esophagus, small intestine, or spleen.
• Total Gastrectomy This procedure is for widespread cancers or those near the esophagus, and it involves removing the entire stomach, nearby lymph nodes and tissues, and the omentum (a layer of fatty tissue that covers the stomach and intestines). During a total gastrectomy, your surgeon will connect your esophagus to your small intestine after removing your stomach. It would require you to eat smaller, more frequent meals. If necessary, your surgeon may also remove parts of nearby organs that may be affected.

Palliative Surgery for Stomach Cancer

• Gastric Bypass (Gastrojejunostomy) A tumor that is blocking the stomach's exit can be bypassed by connecting the upper stomach to the small intestine.
• Subtotal Gastrectomy A part of the stomach is removed to relieve symptoms like bleeding or obstruction.
• Feeding Tube Placement For patients who are unable to consume an adequate amount of food, a tube is placed directly into the stomach or small intestine to provide special high-nutrient food and fluids.
• Endoluminal Stent Placement A stent is inserted to keep passages open that may have been blocked by tumors.
• Endoluminal Laser Therapy Blockages are removed using an endoscope with a laser.

Surgery Complications and Side Effects

You may experience nutritional deficiencies, necessitating dietary changes and possibly vitamin supplements. People who have had stomach cancer surgery typically need to eat smaller, more frequent meals, especially after a total gastrectomy.

• capecitabine
• carboplatin
• cisplatin
• docetaxel
• doxorubicin
• epirubicin
• fluorouracil (5-FU)
• irinotecan
• leucovorin
• oxaliplatin
• paclitaxel
• trifluridine and tipiracil

Chemotherapy Side Effects

General side effects include:

• Gastrointestinal issues such as nausea, vomiting, diarrhea, or constipation
• Loss of appetite
• Hair loss
• Mouth sores
• Increased infection risk from low white blood cell counts
• Increased risk of bleeding and bruising from due low platelet counts
• Fatigue and shortness of breath from low red blood cell counts

Additionally, some chemotherapy drugs carry specific side effects, such as:

• Nerve damage or neuropathy (cisplatin, oxaliplatin, docetaxel, and paclitaxel)
• Heart damage (epirubicin)
• Hand-foot syndrome (capecitabine or 5-FU)
• Severe diarrhea (irinotecan)

Inform your cancer care team about any side effects you experience from chemotherapy drugs, as there are often treatments available to improve these symptoms or other drugs that may be more suitable.

For stomach cancer, doctors use a technique called external beam radiation therapy, which directs radiation beams at the cancer from a machine outside of the body. Two special methods of giving external beam radiation therapy are:

• Three-Dimensional Conformal Radiation Therapy (3D-CRT) Radiation of uniform intensity is aimed at the tumor from many directions, with beams conforming to the shape of the tumor.
• Intensity Modulated Radiation Therapy (IMRT) Smaller radiation beams of different, specific intensities are directed at precise spots of the tumor.

Similar to an X-ray, external beam radiation therapy is painless and each session lasts a few minutes. Treatment usually occurs five days a week for several weeks.

• Skin issues
• Nausea
• Vomiting
• Diarrhea
• Fatigue
• Urinary and bladder problems

HER2-Targeting Drugs

VEGF-Targeting Drugs

Common side effects include high blood pressure, headache, and diarrhea. Less often, more serious side effects can develop, including:

• Blood clots
• Severe bleeding
• The formation of holes or perforations in the stomach or intestines
• Issues with wounds healing

TRK Inhibitors

• Dizziness
• Fatigue
• Nausea
• Vomiting
• Constipation
• Weight gain
• Diarrhea

Monoclonal Antibodies

Zolbetuximab-clzb (Vyloy) is currently the only monoclonal antibody approved for the treatment of stomach cancer. It’s used along with chemotherapy and administered intravenously. 

PD-1 inhibitors are a type of immunotherapy drug that blocks the PD-1 checkpoint protein on T cells (a type of immune system cell). Inhibiting this protein allows the T-cells to attack cancer cells. Two PD-1 inhibitors used to treat stomach cancer are nivolumab (Opdivo) and pembrolizumab (Keytruda).

• Fatigue
• Fever
• Cough
• Nausea
• Itching or skin rash
• Appetite loss
• Muscle or joint pain
• Shortness of breath
• Constipation or diarrhea

In more serious cases, the drugs can cause infusion reactions (similar to allergic reactions) and autoimmune reactions, which may prevent their further use.

• Test the effectiveness of a new drug
• Investigate innovative treatment techniques and therapies
• Identify genetic or molecular markers that predict response to certain treatments
• Assess how interventions or supportive care strategies can improve the quality of life for patients undergoing treatment
• Develop new screening methods or preventive measures to detect stomach cancer earlier or reduce the risk of developing the disease

If you’re interested in finding out about joining a clinical trial, you can start by asking your doctor if you may be eligible to join one. You can also do a search on ClinicalTrials.gov, an online resource maintained by the National Library of Medicine, where clinical studies are registered and updated.

The Takeaway

• Stomach cancer treatment requires a multifaceted approach — including surgery, chemotherapy, radiation, and newer options like targeted therapy and immunotherapy — to remove, shrink, or slow the growth of cancer cells.
• As your healthcare team considers the best treatment plan for you, they will take into account your cancer stage, your overall health, and your personal preferences.
• Integrate palliative care early in your cancer journey to enhance your quality of life and even improve survival.