Quick answer. Stomach cancer, also called gastric cancer, develops in the lining of the stomach and often causes vague symptoms early on, such as persistent indigestion, feeling full quickly and unintended weight loss. Because early signs are easy to dismiss, persistent upper-tummy symptoms, weight loss, vomiting blood or black stools should always be checked by a doctor.
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Stomach cancer, or gastric cancer, is one of the more common cancers in Singapore and across East and Southeast Asia. It develops in the lining of the stomach and tends to cause non-specific symptoms in its early stages, which is why it can be overlooked. Persistent indigestion, a sense of fullness after small meals and gradual weight loss are easy to attribute to everyday stomach upset, yet they can also be early clues. This makes awareness, and a willingness to investigate stubborn symptoms, particularly valuable.
This guide explains what stomach cancer is, the signs and symptoms to watch for, the main risk factors including Helicobacter pylori infection, how it is diagnosed through gastroscopy and biopsy, and the broad treatment options. It is written to be factual and calm. Many people with persistent indigestion do not have cancer, but the symptoms overlap, so checking them out is the responsible step. This guide focuses on the disease itself, distinct from a guide on gastroscopy screening.
At a glance
| Symptom | Often everyday indigestion | Warrants prompt review |
|---|---|---|
| Duration | Brief, settles with diet or antacids | Persistent for weeks despite treatment |
| Appetite | Normal, no change | Feeling full quickly, eating much less |
| Weight | Stable | Unintended weight loss |
| Vomiting | None | Vomiting, or vomiting blood |
| Stools | Normal | Black, tarry stools (possible bleeding) |
What is stomach cancer?
Stomach cancer, also called gastric cancer, is a cancer that begins in the cells lining the stomach. Most are a type called adenocarcinoma. It can develop in any part of the stomach and, if not found early, may spread to nearby lymph nodes and other organs.
Stomach cancer is more common in older adults and is one of the more frequently diagnosed cancers in Singapore, in part reflecting patterns seen across East Asia. It often grows slowly and quietly, so symptoms may not appear, or may seem minor, until the disease is more advanced. That is precisely why persistent upper-abdominal symptoms deserve attention rather than being brushed off as ordinary indigestion.
Symptoms & signs
Early stomach cancer often causes few or vague symptoms. As it progresses, possible signs include:
- Persistent indigestion or heartburn that does not settle
- Feeling full after eating only a small amount (early satiety)
- Loss of appetite and unintended weight loss
- Persistent or recurring upper-abdominal (stomach) pain or discomfort
- Nausea or vomiting
- Vomiting blood, or passing black, tarry stools, which suggest bleeding
- Tiredness or breathlessness from anaemia (low blood count)
None of these symptoms means cancer on its own, and most are caused by far more common conditions. The point is that when they persist, they should be investigated rather than treated indefinitely with antacids.
Causes & risk factors
Stomach cancer arises from changes in the stomach-lining cells, and several factors raise the risk:
- Helicobacter pylori infection: this common stomach bacterium is an important risk factor, as it can cause long-term inflammation of the stomach lining.
- Age and sex: risk rises with age and is somewhat higher in men.
- Diet: diets high in salted, smoked or preserved foods, and low in fresh fruit and vegetables, are associated with higher risk.
- Smoking: tobacco use increases risk.
- Family history and inherited conditions: a close relative with stomach cancer, or certain genetic syndromes, can raise risk.
- Long-standing stomach conditions: chronic gastritis and some changes in the stomach lining.
Treating an H. pylori infection when found is one practical way to reduce risk.
How stomach cancer is diagnosed
The key test for stomach cancer is a gastroscopy, which allows the doctor to look directly at the stomach lining and take samples. Diagnosis typically involves:
- Gastroscopy (upper endoscopy): a thin flexible camera is passed through the mouth into the stomach to inspect the lining and take biopsies of any suspicious areas.
- Biopsy: tissue samples are examined under the microscope to confirm whether cancer is present and what type.
- H. pylori testing: often done as part of assessing stomach symptoms.
- Staging scans: if cancer is confirmed, CT scans and sometimes other imaging assess whether and how far it has spread, to guide treatment.
A gastroscopy is the most reliable way to investigate persistent upper-abdominal symptoms or possible bleeding.
Treatment options
Treatment depends on the type, location and stage of the cancer and the person’s general health, and is planned by a multidisciplinary team. Broad options include:
- Surgery: removing part or all of the stomach (gastrectomy) is a main treatment for cancer that has not spread widely, often with removal of nearby lymph nodes.
- Chemotherapy: may be given before or after surgery, or as the main treatment in more advanced disease.
- Radiotherapy: sometimes used alongside other treatments.
- Targeted therapy and immunotherapy: certain cancers carry markers that make specific drug treatments suitable.
- Endoscopic treatment: very early, superficial cancers may sometimes be removed during endoscopy.
Outcomes depend heavily on the stage at diagnosis, which is why earlier investigation of symptoms matters. Your specialist is the right person to explain the plan and outlook for your specific situation; we do not publish survival figures because they vary so much by case.
When to see a doctor & which specialist
See a doctor promptly if you have:
- Indigestion or upper-tummy discomfort that persists for weeks despite treatment
- Feeling full quickly, loss of appetite, or unintended weight loss
- Persistent nausea or vomiting
Seek urgent care, including A&E, if you vomit blood or pass black, tarry stools, as these can signal bleeding. Call 995 if you also feel faint, have a fast heartbeat, or collapse. For assessment of stomach symptoms and to arrange a gastroscopy, a gastroenterologist is the relevant specialist; you can find one through the best gastroenterologists in Singapore directory. This guide is about the disease itself and differs from a guide focused on gastroscopy screening as a procedure.
Related guides
- Best Gastroenterology Clinics in Singapore — our editorial shortlist
- gastroenterology clinics directory
- Sarcoma
- Croup
- Bronchiolitis
- Pancreatic cancer
- Peptic ulcer
Sources
- NHS – Stomach cancer
- Mayo Clinic – Stomach cancer
- HealthHub Singapore – Cancer
- SingHealth – Stomach cancer
- National Cancer Centre Singapore
Part of our Cancer care & screening guides · Browse all health topics