Stomach Cancer (Gastric Cancer): Symptoms, Risk Factors, and Treatment Options Explained
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR: Stomach cancer (gastric cancer) is a growth of cells that begins in the stomach — the muscular sac in the upper middle belly, just below the ribs, that breaks down and digests food. Nearly all stomach cancers are adenocarcinomas, which start in mucus-producing cells. In the United States, the cancer most often begins at the gastroesophageal junction, where the esophagus meets the stomach. Early-stage stomach cancer can be symptom-free, which is why persistent indigestion, feeling full after small amounts, unexplained weight loss, or black stools should be checked. Treatment is most successful when the cancer is only in the stomach, and many small, early-stage stomach cancers can be cured with an endoscopic procedure or surgery.
Quick Answer
What is it? A growth of cells that starts in the stomach lining and can grow deeper into the stomach wall or spread to other organs.
Most common type: Adenocarcinoma — nearly all stomach cancers are adenocarcinomas.
Who gets it? Most often older adults (average diagnosis age 68; about 60% of cases are in people over 65), with a slightly higher lifetime risk in men.
Early symptoms: May include indigestion, upper belly pain, bloating after eating, feeling full quickly, and heartburn — but early stages can have no symptoms at all.
Warning signs of advanced disease: Unexplained weight loss, extreme tiredness, vomiting (sometimes blood), and black stools.
Main diagnosis test: Upper endoscopy — a thin tube with a tiny camera passed down the throat into the stomach, with a tissue sample (biopsy) taken if something looks suspicious.
Treatment options: Surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, HIPEC for some stage 4 cases, and palliative care for symptom relief.
What Is Stomach Cancer?
Stomach cancer, also called gastric cancer, is a growth of cells that starts in the stomach. The stomach is a muscular sac in the middle of the upper abdomen, just below the ribs. Food passes down the esophagus — the tube that carries swallowed food — through the gastroesophageal junction and into the stomach, where it is broken down and digested.
Stomach cancer can happen in any part of the stomach. In most of the world, stomach cancers develop in the main part of the stomach, called the stomach body. In the United States, stomach cancer is more likely to start near the gastroesophageal junction. Where the cancer begins is one of the factors healthcare providers consider when building a treatment plan, along with the cancer's stage and the type of cells involved.
Stomach cancer develops slowly, usually over many years. Small changes occur in the DNA of stomach cells, telling them to multiply and accumulate into an abnormal growth called a tumor. Several types exist, and most are curable if detected at an early stage. New cases have dropped by about 1.5% every year for the last 10 years.
Treatment is most likely to be successful if the cancer is only in the stomach. The prognosis for people with small stomach cancers is quite good. The problem is timing: most stomach cancers are found when the disease is advanced, when a cure is less likely.
Most common type: Adenocarcinoma — nearly all stomach cancers.
Most common U.S. location: Gastroesophageal junction (where the esophagus meets the stomach).
Average age at diagnosis: 68.
Cases in people over 65: About 60%.
Lifetime risk difference: Slightly higher in men.
Recent trend: New cases down about 1.5% per year for the last 10 years.
What Does Stomach Cancer Feel Like? Recognizing the 12 Possible Symptoms
Stomach cancer doesn't always cause symptoms in its early stages. When symptoms do appear early, they tend to be subtle and easy to confuse with common digestive problems: indigestion and pain in the upper part of the belly.
As the disease progresses, the symptom picture widens. Later stages may cause you to feel very tired, lose weight without trying, vomit — sometimes with blood — and notice black stools. Stomach cancer that spreads to other parts of the body is called metastatic stomach cancer, and it causes symptoms specific to where it spreads.
Early (may have none): Indigestion; pain in the upper belly; feeling bloated after eating; feeling full after eating small amounts; not feeling hungry when expected; heartburn; nausea.
Later stages: Trouble swallowing; belly pain; vomiting; losing weight without trying; feeling very tired; stools that look black; vomiting blood.
If spread to lymph nodes: Lumps you can feel through the skin.
If spread to the liver: Yellowing of the skin and the whites of the eyes.
If spread within the belly (peritoneum): Fluid fills the belly, making it look swollen.
When to See a Doctor
If you have signs and symptoms that worry you, make an appointment with your healthcare provider. Many conditions can cause symptoms like the ones caused by stomach cancer, and your provider might test for those other causes first before testing for stomach cancer.
That is worth understanding clearly: having indigestion does not mean you have stomach cancer. But persistent, worsening symptoms should always be evaluated rather than ignored or self-treated indefinitely.
What Causes Stomach Cancer?
It is not clear exactly what causes stomach cancer. Experts believe most stomach cancers start when something hurts the inside lining of the stomach — for example, an infection in the stomach, long-standing acid reflux, or eating a lot of salty foods. Not everyone with these risk factors gets stomach cancer, though, so more research is needed to find out exactly what causes it.
Here is how the process works at the cellular level. A cell's DNA holds the instructions that tell a cell what to do. When something damages cells in the inner lining of the stomach, those cells can develop changes in their DNA. The changes tell the cells to multiply quickly, and to keep living when healthy cells would die as part of their natural lifecycle. That creates a lot of extra cells in the stomach, and the cells can form a mass called a tumor. Cancer cells can invade and destroy healthy tissue, grow deeper into the stomach wall, and eventually break away and spread to other parts of the body — a process called metastasis.
The 4 Types of Stomach Cancer
Adenocarcinoma — starts in cells that produce mucus. The most common type — nearly all stomach cancers are adenocarcinomas.
Gastrointestinal stromal tumors (GIST) — start in special nerve cells in the wall of the stomach and other digestive organs. A type of soft tissue sarcoma.
Carcinoid tumors — start in neuroendocrine cells, which do some nerve cell functions and some hormone-making work. A type of neuroendocrine tumor.
Lymphoma — starts in immune system cells. Most stomach lymphomas are non-Hodgkin's lymphoma; can occur when the body sends immune cells to the stomach to fight an infection.
What Raises Your Risk? The 8 Known Risk Factors
The following factors increase the risk of stomach cancer. Remember that having a risk factor does not mean you will get the disease — not everyone with these factors develops stomach cancer.
Gastroesophageal reflux disease (GERD) — ongoing problems with stomach acid backing up into the esophagus.
Diet high in salty and smoked foods — protect your stomach by limiting these foods.
Diet low in fruits and vegetables — include a variety of colorful fruits and vegetables in your diet each day.
Helicobacter pylori (H. pylori) infection — an infection in the stomach caused by this germ.
Gastritis — swelling and irritation of the inside of the stomach.
Smoking — increases risk of stomach cancer and many other cancers; smoking doubles your risk of stomach cancer.
Stomach polyps — growths of noncancerous cells in the stomach.
Family history — of stomach cancer, or of genetic syndromes that raise risk — hereditary diffuse gastric cancer, Lynch syndrome, juvenile polyposis syndrome, Peutz-Jeghers syndrome, and familial adenomatous polyposis.
Stomach cancers can also be hereditary. People sometimes pass on DNA mutations to their children that raise the risk of stomach cancer. Factors that raise suspicion a stomach cancer is hereditary include cancer at a younger age, a history of other cancers, or multiple cancers in the family.
How to Lower Your Risk
To lower the risk of stomach cancer, you can eat plenty of fruits and vegetables each day, reduce the amount of salty and smoked foods you eat, and stop smoking — if you smoke, quit; if you don't, don't start. Quitting is very hard, so ask your healthcare provider for help. And tell your healthcare provider if stomach cancer runs in your family: people with a strong family history might qualify for stomach cancer screening, which can detect the disease before it causes symptoms.
How Is Stomach Cancer Diagnosed and Staged?
From First Test to Final Answer
Diagnosis usually begins with an upper endoscopy: a thin tube with a tiny camera on the end is passed down the throat and into the stomach so a provider can look for signs of cancer. If something that looks like cancer is found, a biopsy removes some tissue for testing — special tools pass down the tube to collect the sample, which is sent to a lab.
After a cancer diagnosis, additional tests determine the stage — how advanced the cancer is and what it means for your prognosis.
Upper endoscopy — the main test; a tiny camera looks inside the stomach, and biopsies are taken during the procedure.
Blood tests — cannot diagnose stomach cancer, but give clues — for example, liver tests can show problems caused by cancer that has spread to the liver.
Circulating tumor DNA test — a blood test that looks for pieces of cancer cells in the blood; used only in certain situations, such as advanced cancer when a biopsy isn't possible.
Stomach (endoscopic) ultrasound — a tube with a camera and ultrasound tool goes down the throat; shows how far the cancer has grown into the stomach wall and images nearby lymph nodes; can guide a needle to collect tissue.
CT scan — imaging that can show cancer cells in nearby lymph nodes or other body parts.
PET scan — imaging used to look for spread.
Barium swallow — a special X-ray of the digestive tract.
Surgery (laparoscopy) — used when imaging tests don't give a clear picture; looks directly for spread, including small bits of cancer on the liver or in the belly.
Understanding the Stages (0 to 4)
Stage 0: cancer is small and only on the inside surface of the stomach.
Stage 1: cancer has grown into the inner layers of the stomach.
Stages 2–3: cancer grows deeper into the stomach wall and may have spread to nearby lymph nodes.
Stage 4: cancer has grown through the stomach into nearby organs or spread to other body parts (metastatic); when stomach cancer spreads, it often goes to the lymph nodes, the liver, or the peritoneum.
Separate staging systems can be used after surgery or after chemotherapy.
What About Your Prognosis?
Prognosis — how likely it is that the cancer will be cured — is based largely on the stage. For stomach cancer, the prognosis for early-stage cancer is very good. As the stage gets higher, the chances of a cure get lower. Even when stomach cancer can't be cured, treatments may control the cancer to prolong your life and keep you comfortable.
Factors that influence prognosis include the type of cancer, the stage, where the cancer sits within the stomach, your overall health, whether the cancer is removed completely with surgery, and whether it responds to chemotherapy or radiation therapy.
Screening: Detecting Cancer Before Symptoms
Sometimes tests are used to look for stomach cancer in people who don't have symptoms — this is called stomach cancer screening, and the goal is to detect cancer when it is small and more likely to be cured. In the United States, screening is reserved for people at high risk, such as those with a family history or a genetic syndrome linked to stomach cancer. Upper endoscopy is the most common screening test.
How Is Stomach Cancer Treated?
Treatment options depend on the cancer's location within the stomach, its stage, your overall health, and your preferences. The options include surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, and palliative care.
Surgery
The goal of surgery is to remove all of the cancer. For small stomach cancers, surgery might be the first treatment. If the cancer grows deeper into the stomach wall or spreads to the lymph nodes, other treatments might be used first.
Endoscopic mucosal resection — very small cancers are cut away from the inside lining of the stomach through a tube passed down the throat; used for stage 1 cancer growing on the inner lining.
Subtotal gastrectomy — the surgeon removes the part of the stomach affected by cancer plus some healthy tissue around it; used for cancer near the small intestine.
Total gastrectomy — the entire stomach and some surrounding tissue are removed and the esophagus is connected to the small intestine; used for cancers closest to the esophagus.
Lymph node removal — lymph nodes in the belly are removed and tested for cancer, alongside other operations.
Symptom-relief surgery — removing part of the stomach to relieve symptoms of a growing advanced cancer when other treatments haven't helped.
For stages 2 and 3, chemotherapy and radiation therapy might be used before surgery to shrink the cancer, making complete removal easier. If stage 4 cancer has grown through the stomach into nearby organs, surgery might remove the cancer along with parts of nearby organs; if it can't be removed completely, surgery might still help control symptoms.
Chemotherapy
Chemotherapy uses chemicals to kill cancer cells. Systemic chemotherapy — medicines that travel through the whole body, given through a vein or as pills — is the most common type. Hyperthermic intraperitoneal chemotherapy (HIPEC) puts heated chemotherapy medicines directly into the belly right after surgery; it stays in place for a set time and is then drained. HIPEC is an experimental option for stage 4 cancer that extends through the stomach into nearby organs.
Neoadjuvant chemotherapy (before surgery, stages 2–3) — shrinks the cancer so it's easier to remove.
Adjuvant chemotherapy (after surgery) — used if there's risk that cancer cells were left behind.
Systemic chemotherapy (without surgery) — for cancer that's too advanced or when a patient isn't healthy enough for surgery; may help control cancer symptoms.
Chemotherapy might not be needed for stage 1 cancer, especially if surgery removed all of it with a low risk of return. It can be used alone or combined with radiation therapy.
Radiation Therapy
Radiation therapy uses high-powered beams of energy — from X-rays, protons, or other sources — to kill cancer cells, targeting precise points on the body. It is often given at the same time as chemotherapy, sometimes called chemoradiation.
Neoadjuvant radiation (before surgery, stages 2–3) — shrinks the cancer so it's easier to remove.
Adjuvant radiation (after surgery) — used when the cancer can't be removed completely.
Palliative radiation (advanced disease) — helps relieve symptoms when surgery isn't possible.
Radiation might not be needed for stage 1 cancer or after surgery that removed all of the cancer with low return risk.
Targeted Therapy and Immunotherapy
Targeted therapy uses medicines that attack specific chemicals present within cancer cells; blocking these chemicals can cause cancer cells to die. Your cancer cells are tested first to see if targeted therapy is likely to work. It is often used with systemic chemotherapy and typically used for advanced cancer, including stage 4 disease and cancer that comes back after treatment.
Immunotherapy is medicine that helps your body's immune system kill cancer cells. Cancer cells survive by hiding from the immune system; immunotherapy helps immune cells find and kill them. It is sometimes used to treat advanced cancer, including stage 4 disease or recurrence.
Palliative Care
Palliative care is a special type of healthcare that helps you feel better when you have a serious illness. A team of providers — doctors, nurses, and other trained professionals — works to relieve pain and other symptoms and to improve quality of life for you and your family. Palliative care is an extra layer of support during cancer treatment and can be used alongside surgery, chemotherapy, or radiation. When it is used with all other appropriate treatments, people with cancer may feel better and live longer.
Coping and Support: Being the Best Partner to Your Medical Team
A cancer diagnosis can be overwhelming and frightening, and it may take time to adjust. Learn enough to make decisions about your care. Ask your provider to write down the details of your cancer — the type, the stage, and your treatment options — and use those details to research the benefits and risks of each option. Connect with other cancer survivors through support groups in your area or online message boards. And stay active: being diagnosed doesn't mean you have to stop doing the things you enjoy.
Communication matters more than you might expect. As one oncologist puts it, if your doctor and medical team do not hear from you, they assume you're doing well. Keep communicating your symptoms, concerns, and anything related to your care — never hesitate to ask questions.
And if you wonder about getting a second opinion: it is always advisable to get one from a specialized center that frequently treats stomach cancer, since these cancers are generally rare in the United States. Specialized-center doctors can often work with your local doctors as a team.
Preparing for Your Appointment: Questions That Matter
Start with your usual healthcare provider if you have symptoms that worry you. You may be referred to a gastroenterologist — a doctor who diagnoses and treats problems in the digestive system — and after a diagnosis, to an oncologist (cancer doctor) or a surgeon who specializes in operating on the digestive tract.
Before your appointment, note any pre-appointment restrictions, write down all symptoms (even ones that seem unrelated), record key personal information, list every medication, vitamin, and supplement, track what improves or worsens your symptoms, and consider bringing a family member or friend along to help absorb the information.
What type of stomach cancer do I have?
How advanced is my stomach cancer?
What other kinds of tests do I need?
What are my treatment options?
How successful are the treatments?
What are the benefits and risks of each option?
Is there one option you feel is best for me?
How will treatment affect my life? Can I continue to work?
Should I seek a second opinion? What will that cost, and will my insurance cover it?
Are there brochures or other printed material I can take with me? What websites do you recommend?
Expect your provider to ask about when your symptoms began, whether they are continuous or occasional, how severe they are, and what seems to improve or worsen them.
Conclusion: Early Evaluation Is Your Best Defense
Stomach cancer is a disease where timing changes everything. Early-stage cancer that is only in the stomach is often curable — many people with small stomach cancers can expect to be cured. Yet most stomach cancers are found at an advanced stage, when cure is less likely. The single most actionable step you can take is to stop treating persistent indigestion, early fullness, unexplained weight loss, or black stools as "just stress" or "just aging," and see a healthcare provider instead.
Your next step: if you or a loved one has stomach symptoms that have lasted more than a few weeks, or any of the warning signs described above, book an appointment this week. If you've already been diagnosed, ask about a second opinion at a specialized center and take the question list above into your next visit.
Frequently Asked Questions
Is stomach cancer curable?
Yes — but it depends on the stage and other factors. For stomach cancer that hasn't traveled to a different organ, a cure is possible and is the main goal of treatment. An endoscopic procedure or surgery can achieve cure, and adding chemotherapy to surgery in some circumstances can increase the chance of cure. In patients with metastatic disease, cure is rarely achieved; the treatment goal shifts to prolonging life and improving quality of life.
What are the first signs of stomach cancer?
Early-stage stomach cancer may cause no symptoms at all. When symptoms do appear, they commonly include indigestion, pain in the upper part of the belly, feeling bloated after eating, feeling full after eating small amounts, heartburn, and nausea. Later stages may cause trouble swallowing, unexplained weight loss, extreme tiredness, vomiting, vomiting blood, and black stools.
Is stomach cancer hereditary?
It can be. People sometimes pass on DNA mutations to their children that raise the risk of stomach cancer. Suspicion of a hereditary stomach cancer rises when cancer occurs at a younger age, when there is a history of other cancers, or when multiple cancers occur in the family. Genetic syndromes such as hereditary diffuse gastric cancer, Lynch syndrome, juvenile polyposis syndrome, Peutz-Jeghers syndrome, and familial adenomatous polyposis also raise risk.
How is stomach cancer staged?
Stages are numbered 0 to 4. Stage 0 cancer is small and only on the inside surface of the stomach. Stage 1 has grown into the inner layers. Stages 2 and 3 grow deeper into the stomach wall and may have spread to nearby lymph nodes. Stage 4 has grown through the stomach into nearby organs or spread to other parts of the body. Staging is determined using endoscopy, biopsy, blood tests, ultrasound, CT and PET scans, and sometimes surgery.
What is the survival rate for stomach cancer?
The prognosis for early-stage stomach cancer is very good — many people with small stomach cancers can expect to be cured. As the stage gets higher, the chances of a cure get lower. Even when a cure isn't possible, treatments can control the cancer, prolong life, and keep patients comfortable.
Who is most at risk for stomach cancer?
Stomach cancer most commonly affects older people — the average age at diagnosis is 68, and about 60% of cases occur in people older than 65, with a slightly higher lifetime risk in men. Risk factors include GERD, a diet high in salty and smoked foods, a diet low in fruits and vegetables, H. pylori infection, gastritis, smoking (which doubles risk), stomach polyps, and a family history of stomach cancer or related genetic syndromes.
Related Reading
References
Health information, not medical advice. This article is for general education and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your own health, and seek emergency care for urgent symptoms.
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