ARTICLE

Stomach Cancer Symptoms:

Pain, Warning Signs & Risk Factors Guide

15-min read

Updated on 2026-7-30

Author: AIA Content Editorial Team

Older man speaking with a doctor about stomach cancer symptoms, abdominal pain, digestive issues, and early warning signs.

Stomach pain and indigestion are common health issues. However, if the symptoms persist, could they be early warning signs of stomach cancer? According to data from the Centre for Health Protection under the Hong Kong Department of Health, there were 1,284 new cases of stomach cancer in Hong Kong in 2023, and stomach cancer ranked sixth among the leading causes of cancer deaths in the city¹. As the early symptoms of stomach cancer are very similar to general gastrointestinal discomfort, many patients may underestimate the condition and miss the best timing for treatment. This article explains the symptoms of early, middle, and late-stage stomach cancer, helps you distinguish between ordinary stomach pain and stomach cancer, and explores high-risk factors and medical options to support early prevention.

How to Differentiate Between Ordinary Stomach Pain and Early Warning Signs of Stomach Cancer?

Stomach cancer refers to a malignant tumour formed by abnormal growth of cells in the stomach lining. Many people may mistake early stomach cancer symptoms for ordinary stomach pain, but there are subtle differences in how the two conditions develop and persist.

Early Symptoms: Subtle Differences from General Gastrointestinal Discomfort

In the early stages of stomach cancer, patients may have no obvious symptoms at all, or may only experience symptoms that are very similar to indigestion, heartburn, mild nausea, or loss of appetite². Ordinary stomach pain is usually related to overeating, stress, or acute gastroenteritis. In most cases, symptoms can improve within a few days after taking common stomach medication or adjusting one's diet. However, if the discomfort does not improve after taking stomach medication and persists for more than two weeks, it may no longer be simple gastrointestinal discomfort. Instead, it could be an important warning signal from the body, and medical advice should be sought as early as possible.

Medical Warning Signs: Physical Changes That Require Attention

As the tumour gradually grows, the signs of stomach cancer may become more obvious and severe. If the following body changes occur, you should stay alert and seek professional medical diagnosis as soon as possible³:

Black or bloody stool: When a stomach tumour causes internal bleeding, the blood may be digested as it passes through the intestines, causing the stool to appear black and tar-like.
Persistent vomiting or even vomiting blood: The tumour may block the stomach outlet, leading to frequent vomiting after eating. In severe cases, the vomit may contain blood.
Difficulty swallowing: If the tumour grows near the junction between the stomach and the oesophagus, patients may feel as if food is stuck when eating.
Rapid weight loss: Without intentional dieting, patients may experience significant unexplained weight loss within a short period due to loss of appetite and the body's energy being consumed by the tumour.
Abdominal lump or fluid accumulation: The abdomen may feel unusually swollen, and in some cases, a hard lump may be felt.

Rare Skin Sign: Acanthosis nigricans

In addition to the digestive symptoms mentioned above, a small number of stomach cancer patients may develop a rare skin sign known as Acanthosis Nigricans. This condition involves skin pigmentation and thickening. Patients may develop darkened, thickened skin with a velvety, rough texture around the neck, armpits, palms, finger joints, or face. Although this sign is more commonly associated with endocrine disorders or diabetes, in some cases, it may also be a warning sign of an underlying malignant tumour, such as stomach cancer⁴.

Who Is at High Risk? Key Risk Factors for Stomach Cancer

The causes of stomach cancer involve multiple factors. Understanding whether you belong to a high-risk group can help you take preventive action early. The following are major risk factors for stomach cancer:

Age and gender: The incidence of stomach cancer increases with age. According to the Hong Kong Cancer Registry, more than half of new cancer cases occur in people aged 65 or above⁵. In addition, men generally have a higher risk of developing stomach cancer than women⁵.
Helicobacter pylori infection: Helicobacter pylori is a type of bacteria that can live in the stomach. The World Health Organization has classified it as a Group 1 carcinogen⁶. Long-term infection may cause chronic gastritis and gastric ulcers, increasing the risk of stomach cancer.
Unhealthy dietary habits: Long-term consumption of high-salt, preserved, and smoked foods, such as salted fish, sausages, and cured meat, may increase cancer risk, as nitrites in these foods may be converted into carcinogenic substances in the body. At the same time, insufficient intake of fresh vegetables and fruits may weaken the body's resistance.
Family history: If close relatives, such as parents or siblings, have had stomach cancer, the risk of developing the disease may be more than twice that of the general population⁷.
Other lifestyle habits: Long-term smoking and excessive alcohol consumption can continuously irritate the stomach lining and increase the risk of cellular changes.

The Key to Early Detection: Professional Diagnosis and Recommended Screening Approaches

Because early-stage stomach cancer symptoms are not obvious, "early detection and early treatment" is the key to improving the chance of recovery. Modern medicine provides a range of effective diagnostic tools to help doctors accurately assess the condition:

Gastroscopy: A doctor inserts a flexible tube with a small camera through the mouth into the stomach to directly observe the stomach lining. If suspicious lesions are found, tissue samples can be taken immediately for laboratory testing. This is currently one of the most accurate methods for diagnosing stomach cancer.
Imaging tests: Tests such as CT scans or PET-CT scans are mainly used to assess the size and location of the tumour and whether it has spread to lymph nodes or other organs.

For high-risk individuals with a family history of stomach cancer, previous Helicobacter pylori infection, or long-term stomach discomfort, it is advisable to consult a doctor after the age of 40 and consider regular screening options such as gastroscopy to better monitor gastrointestinal health.

The Importance of Medical Resource Planning

In the unfortunate event of a stomach cancer diagnosis, patients and their families may face not only physical and emotional stress, but also the substantial financial burden associated with prolonged treatment. Treatment options for stomach cancer are generally determined according to the stage of the disease and may include surgical procedures, such as partial or total gastrectomy, chemotherapy, targeted therapy, and the more recently developed immunotherapy. Receiving this series of comprehensive treatments in private medical institutions can easily cost hundreds of thousands, or even over one million, Hong Kong dollars, placing pressure on family financial arrangements.

In view of potential future healthcare needs and related treatment expenses, individuals may make appropriate medical and financial plans based on their personal circumstances. For some people, incorporating medical protection into their overall planning may help reduce immediate financial pressure when treatment is required, allowing patients to focus more fully on treatment and recovery. When conducting financial planning, priority may be given to plans with broad coverage and sufficient benefit limits. Based on your personal budget and healthcare needs, you may learn more about AIA's medical protection solutions to help ensure access to quality medical support when needed and make further preparations for the future.

Stomach Cancer FAQs

There is no need to be overly anxious. Simple stomach pain is usually associated with overeating, stress, or acute gastroenteritis. In most cases, it can be relieved through dietary adjustments or medication, and does not necessarily indicate stomach cancer. However, if your stomach discomfort persists for more than two weeks without improvement, or is accompanied by warning signs such as black stool or rapid weight loss, you should seek professional medical advice as soon as possible and consider undergoing a gastroscopy to rule out malignancy.

It may take some time for abnormal growth of stomach lining cells to develop into a malignant tumour, and there are often no obvious symptoms in the early stages. According to medical recommendations, if you have high-risk factors such as a family history of stomach cancer, previous Helicobacter pylori infection, or long-term stomach discomfort, you may consult a doctor after the age of 40 and consider regular screening such as gastroscopy. This helps put the principle of "early detection and early treatment" into practice.

Long-term consumption of high-salt, preserved, and smoked foods, such as salted fish, sausages, and cured meat, may increase the risk of stomach cancer because nitrites in these foods may be converted into carcinogenic substances in the body. In daily life, increasing intake of fresh fruits and vegetables may help strengthen the body's resistance. Avoiding long-term smoking and excessive alcohol consumption can also reduce continuous irritation to the stomach lining.

Current medical technology is already highly advanced. Doctors will develop a comprehensive treatment plan based on the tumour's stage and the patient's physical condition. The main treatment options include surgery, such as partial or total gastrectomy, chemotherapy, targeted therapy, and the more recently developed immunotherapy. Since this series of treatments may be very costly, it is advisable to review your medical insurance arrangements early and carry out medical resource planning. This can help ensure access to appropriate treatment when needed while reducing the pressure of a heavy financial burden.

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^1.Centre for Health Protection. Stomach Cancer. 2026. https://www.chp.gov.hk/en/healthtopics/content/25/55.html

^2.Hong Kong Integrated Oncology Centre. Blackening of palms could be early stage stomach cancer. 2025. https://www.hkioc.com.hk/en/all-you-need-to-know-about-stomach-cancer-symptoms/

^3. reVIVE Oncology and Cancer Centre. Stomach Cancer Understanding the causes and symptoms of stomach cancer, effective prevention and treatment, improve survival rates https://reviveonco.com/en/stomachcancer/

^4. HKMED. International rare cases of gastric cancer: Beware of black palms or have gastric cancer. 2020. https://hongkongmed.com/%E5%9C%8B%E9%9A%9B%E7%BD%95%E8%A6%8B%E8%83%83%E7%99%8C%E6%A1%88%E4%BE%8B%EF%BC%9A%E7%95%99%E6%84%8F%E6%89%8B%E6%8E%8C%E7%99%BC%E9%BB%91%E6%88%96%E5%B7%B2%E6%82%A3%E4%B8%8A%E8%83%83%E7%99%8C/

^5.Hong Kong Cancer Registry, Hospital Authority. Overview of Hong Kong Cancer Statistics of 2023. 2023. https://www3.ha.org.hk/cancereg/pdf/overview/Overview%20of%20HK%20Cancer%20Stat%202023.pdf

^6. INDICAID. Gastric Cancer Caused by H. pylori Infection? H. Pylori - Group 1 Carc. 2023. https://www.indicaid.com/blogs/helicobacter-pylori/group-1-carcinogen?srsltid=AfmBOoo9XT7jY46mT7ismBXbcwhlu5FTk5Crx84SJtpqxqbU_QEyW28n

^7.American Cancer Society, "Prostate Cancer Risk Factors", 2023 https://www.cancer.org/cancer/types/prostate-cancer/causes-risks-prevention/risk-factors.html

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Stomach Cancer Symptoms:

Pain, Warning Signs & Risk Factors Guide

How to Differentiate Between Ordinary Stomach Pain and Early Warning Signs of Stomach Cancer?

Early Symptoms: Subtle Differences from General Gastrointestinal Discomfort

Medical Warning Signs: Physical Changes That Require Attention

Rare Skin Sign: Acanthosis nigricans

Who Is at High Risk? Key Risk Factors for Stomach Cancer

The Key to Early Detection: Professional Diagnosis and Recommended Screening Approaches

The Importance of Medical Resource Planning