Stomach cancer symptoms: What are the signs of gastric cancer?

Read our blog to discover the symptoms of stomach cancer. We discuss the symptoms at both an early and advanced stage, as well as risk factors for stomach cancer.

Patient with doctor checking on stomach diseases

Stomach cancer, also known as gastric cancer, is cancer found anywhere in the stomach or stomach wall. It is fairly rare in the UK; roughly 1 in every 10,000 people is diagnosed with stomach cancer. Keep reading to learn the symptoms of stomach cancer.

What is stomach cancer?

Stomach cancer begins when cells in the stomach grow in an uncontrolled way. It can form anywhere in the stomach, but it most commonly affects the inner stomach lining.

It can also start in the stomach wall (gastrointestinal stromal tumours - GIST), the stomach’s immune system cells (non-Hodgkins lymphoma), and the stomach’s hormone cells (neuroendocrine cancers).

Unfortunately, the symptoms of early-stage stomach cancer are often minor at most. So it is usually diagnosed at stages 3 and 4. People display no symptoms until these stages usually, which can make it harder to know something is wrong.

There are 5 stages of stomach cancer: stages 0 to 4. It can take years for stomach cancer to develop as it tends to be a slow-growing cancer

What are the symptoms of stomach cancer?

Most of the symptoms of stomach cancer are also signs of something else, such as irritable bowel syndrome (IBS), especially the early signs. That is why we recommend speaking to your doctor about any new symptoms instead of trying to self-diagnose them.

We understand that new symptoms affecting your stomach can be worrying and may affect your day-to-day life. If you feel your doctor has missed something, we do offer a second opinion service.

Visit us at The Royal Marsden for stomach cancer testing; learn more on our Tumour: GI Cancer page.

Early warning signs of stomach cancer

The early signs of gastric cancer, such as feeling or being sick, are common and are usually not due to stomach cancer. Though, if you notice the following symptoms, speak to your doctor.

Feeling full

You might find that you feel full soon after eating, even with small meals. This fullness may last longer than your usual feeling of being full and may be uncomfortable.

Heartburn or acid reflux

This feels like a burning sensation in your chest and is due to rising stomach acid. Alongside this, people often experience a cough, a hoarse voice, and bad breath.

Indigestion (dyspepsia)

Indigestion occurs when your body struggles to digest food. Symptoms include burping a lot after eating and feeling bloated in your upper abdomen.

Stomach pain

You may feel discomfort in your stomach and have upper abdominal pain. This is usually above your belly button (navel area). You might also experience pain behind your breastbone (sternum).

Signs of advanced stomach cancer

Advanced stomach cancer means it has spread to other parts of the body. Keep reading to learn the signs of advanced cancer.

Weight loss

Unexplained or unintentional weight loss may be a sign of advanced cancer, though this isn’t usually the cause. You might also have a low appetite, meaning you might be eating less than you usually would. If you experience unintended weight loss, you must speak to your doctor about the possible cause.

Bleeding and blood in your stools

You can experience bleeding with early and advanced cancer. Over time, this can lead to anaemia - a reduced number of red blood cells. With anaemia, you may feel tired and breathless. Rarely you might have blood in your vomit.

Another sign that your stomach could be bleeding is finding blood in your stools (poo). Your stools might be dark, almost black. Dark stools can also occur if you are taking iron tablets.


Feeling sick (nausea) and being sick (vomiting) can be a sign of early or advanced stomach cancer. In the earlier stages of stomach cancer, you may find that you feel sick without vomiting.

You may vomit if you have a blockage in your stomach, preventing food from passing through your digestive system.

Difficulty swallowing

Problems swallowing are called dysphagia. Stomach cancer can cause difficulty swallowing when a tumour blocks or narrows the food pipe (oesophagus).

This is also a sign of oesophageal cancer or head and neck cancer. Watch our video to learn more: What are the symptoms of head and neck cancer?


Jaundice is yellowing of the skin and eyes. If you experience jaundice with stomach cancer, it is a sign that it has spread to your liver.

Without a stomach cancer diagnosis, this would usually indicate a problem with your liver. You might also have itchy skin, dark urine, and pale stools. Seek urgent care if you experience these symptoms.

If you suspect you have the symptoms of stomach cancer, speak to a doctor for advice. They can refer you for stomach cancer testing.

How do we test for stomach cancer?

Stomach cancer is often at an advanced stage at diagnosis. This is why you must speak to a doctor about any concerning symptoms. While they will usually not be due to stomach cancer, it can help us catch it earlier if it is.

Your doctor will feel your stomach and check for any lumps. They are also likely to do a blood test. Your doctor should also discuss your medical and family history to determine your risk of stomach cancer.

If your doctor suspects stomach cancer, they may refer you for an upper endoscopy. You are more likely to be referred for an endoscopy if you are already at risk for stomach cancer. During an endoscopy, your doctor can also take a biopsy (small tissue sample) to test for abnormal cells in your stomach.

You may also need scans, such as an ultrasound scan, a CT scan or a PET scan.

If your doctor decides that it is unlikely you have stomach cancer, but you are still concerned, you can visit us at The Royal Marsden for our second opinion service.

Request a second opinion.

Who gets stomach cancer?

Anyone can get stomach cancer, though it is more common in men than women. People over the age of 45 are also more at risk of developing stomach cancer. Other risk factors for stomach cancer include:

  • A family history of stomach cancer, especially a sibling or parent
  • Gastroesophageal reflux disease (GERD/ GORD)
  • Infection with Helicobacter pylori (H. pylori)
  • Long-term stomach inflammation (gastritis)
  •  Lifestyle factors, such as smoking, being overweight or obese, and drinking alcohol in excess
  • Diet factors, such as a diet high in salty, pickled and smoked foods; a diet low in fibre, fruit and vegetables

If you are worried about the risk of stomach cancer and are showing signs or symptoms, visit our same-day gastrointestinal cancer service.