How is Stomach Cancer Treated?

The treatment for stomach cancer depends on the stage of the cancer, the location of the tumor in the stomach, the molecular features of the tumor, your overall health, and your personal preferences. Treatment is best planned by a multidisciplinary team of specialists that includes a surgical oncologist, a medical oncologist, a radiation oncologist, a gastroenterologist, and a dietitian.

Getting a second opinion from an experienced stomach cancer team, particularly at a major cancer center, is normal and often very helpful.

Endoscopic treatment for very early stomach cancer

For very early stomach cancers confined to the innermost layer of the stomach lining, endoscopic resection can remove the cancer without surgery. This is most commonly used in countries with active screening programs where early cancers are frequently found. Two main techniques are used:

• Endoscopic mucosal resection. A technique in which the area of cancer is lifted with a fluid injection and removed using a snare or cutting device passed through the endoscope.

• Endoscopic submucosal dissection. A more technically demanding technique that allows larger areas of cancer to be removed as a single piece. It is preferred when the cancer is larger or when precise assessment of the removed edges is needed.

Endoscopic treatment is only appropriate for cancers that meet strict criteria, including small size, no invasion into the deeper layers of the stomach, and no high-risk features on the pathology. A specialist gastroenterologist or surgical team at a high-volume center should evaluate whether endoscopic treatment is an option.

Surgery

Partial gastrectomy

A partial gastrectomy removes the part of the stomach containing the cancer along with a margin of healthy tissue and nearby lymph nodes. It is used when the tumor is located in the lower part of the stomach and can be removed while leaving enough stomach for digestion. The remaining stomach is reconnected to the small intestine.

Total gastrectomy

A total gastrectomy removes the entire stomach along with nearby lymph nodes. It is required when the tumor is in the upper stomach or body of the stomach, or when it is too extensive to be removed while leaving any stomach. After a total gastrectomy, the esophagus is connected directly to the small intestine. This permanently changes how food moves through the digestive system and requires significant dietary adjustments.

Lymph node removal

Removing and examining lymph nodes is a critical part of stomach cancer surgery. It provides important staging information and reduces the risk of cancer coming back in the abdomen. Guidelines recommend removing at least 15 to 16 lymph nodes for adequate staging. Extended lymph node removal, called D2 dissection, is standard at specialized centers and improves outcomes compared to more limited lymph node removal.

Minimally invasive surgery

Laparoscopic and robotic approaches to stomach cancer surgery are used at specialized centers, particularly for early-stage cancers. These approaches use smaller incisions and may lead to faster recovery. Whether minimally invasive surgery is appropriate depends on the location and stage of the cancer and the experience of the surgeon.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells throughout the body. For stomach cancer, chemotherapy is used in several ways:

Perioperative chemotherapy

Perioperative chemotherapy means giving chemotherapy both before and after surgery. This approach is the standard of care for resectable, meaning surgically removable, stomach cancer in many countries. Giving chemotherapy before surgery can shrink the tumor, making it easier to remove, and treating occult spread. Giving chemotherapy after surgery reduces the risk of the cancer coming back. Common regimens include FLOT, which uses fluorouracil, leucovorin, oxaliplatin, and docetaxel.

Adjuvant chemotherapy and chemoradiation

In the United States, a common approach after surgery is to give chemotherapy combined with radiation therapy, an approach called chemoradiation or adjuvant chemoradiation. The most studied regimen uses capecitabine or fluorouracil together with radiation therapy after surgery.

Chemotherapy for advanced stomach cancer

For stomach cancer that cannot be removed with surgery or has spread to distant organs, chemotherapy is the backbone of treatment. Common first-line regimens include combinations of platinum drugs such as oxaliplatin or cisplatin with fluoropyrimidines such as fluorouracil or capecitabine. These are typically combined with immunotherapy drugs. Second-line and later options include drugs such as paclitaxel, ramucirumab, irinotecan, and others.

Targeted therapy

Targeted therapies attack specific proteins that help cancer cells grow and survive.

• Trastuzumab. Trastuzumab blocks the HER2 protein, which is overproduced in about 15 to 20 percent of advanced stomach adenocarcinomas. Adding trastuzumab to chemotherapy has been shown to improve survival in HER2-positive stomach cancer. All patients with advanced stomach cancer should have their tumor tested for HER2. Trastuzumab deruxtecan is a newer antibody-drug conjugate that links trastuzumab to a chemotherapy payload and has shown strong activity in HER2-positive stomach cancer after prior treatment.

• Ramucirumab. Ramucirumab blocks a protein called VEGFR-2, which tumors use to grow new blood vessels. It is approved for use after first-line chemotherapy, both alone and in combination with paclitaxel, for advanced stomach cancer.

• FGFR2b inhibitors. Bemarituzumab and other drugs targeting FGFR2b are being studied for stomach cancers that overexpress this protein. Early results have been promising.

Immunotherapy

Immunotherapy has become an important part of first-line treatment for advanced stomach cancer.

• Nivolumab. A PD-1 checkpoint inhibitor that is now approved in combination with chemotherapy as first-line treatment for advanced stomach and gastroesophageal junction adenocarcinoma. Adding nivolumab to chemotherapy improves survival compared to chemotherapy alone, particularly in tumors with higher PD-L1 expression.

• Pembrolizumab. Another PD-1 checkpoint inhibitor approved in combination with chemotherapy for advanced stomach cancer, particularly in tumors with high PD-L1 combined positive scores. It is also approved for any solid tumor, including stomach cancer, that is mismatch repair deficient or microsatellite instability-high.

• Dostarlimab. A checkpoint inhibitor approved for mismatch repair deficient solid tumors, including stomach cancer.

Radiation therapy

Radiation therapy uses high-energy beams to destroy cancer cells. Its role in stomach cancer varies by stage and by country:

• Adjuvant chemoradiation. After surgery, radiation therapy combined with chemotherapy is used in some patients to reduce the risk of cancer coming back in the area of the original tumor. This approach is more commonly used in the United States than in Europe and Asia.

• Palliative radiation. For patients with advanced stomach cancer, radiation therapy can help relieve symptoms such as bleeding, pain, or difficulty swallowing caused by the tumor.

Supportive and palliative care

Treating the symptoms of cancer and the side effects of treatment is called supportive and palliative care. It is an important part of cancer care at every stage of illness, not just at the end of life. Supportive care for stomach cancer may include:

• Nutritional support. Stomach cancer and its treatment significantly affect the ability to eat and absorb nutrients. Working with a registered dietitian with experience in stomach cancer and digestive disorders is essential. After gastrectomy, patients need to learn new eating patterns, including eating smaller and more frequent meals.

• Management of dumping syndrome. After stomach surgery, food may move too quickly from the stomach remnant or surgical connection into the small intestine, causing symptoms such as diarrhea, sweating, nausea, and lightheadedness. Dietary adjustments and sometimes medications can help manage this.

• Vitamin and mineral supplementation. After gastrectomy, the body can no longer absorb vitamin B12 without intrinsic factor produced by the stomach. Lifelong B12 supplementation, typically by injection, is required. Supplementation with iron, calcium, vitamin D, and other nutrients is also often needed.

• Pain management.

• Management of treatment-related side effects such as fatigue, nausea, and neuropathy from chemotherapy.

• Mental health support and counseling.

There is a common misconception that palliative care is only given at the end of life. Palliative and supportive care can be provided at any time during cancer treatment to improve comfort and quality of life.

Follow-up care after treatment

After stomach cancer treatment, regular follow-up is essential. Follow-up visits help detect signs of recurrence early and address the nutritional and digestive changes that result from stomach surgery. Follow-up typically includes physical examinations, blood tests to monitor nutritional status, and imaging as clinically indicated. Nutritional monitoring, including vitamin B12 levels and other nutrients, is a lifelong part of care after gastrectomy. Appointments are usually more frequent in the first two years after treatment, when recurrence risk is highest, and continue for at least five years.