How many times have you brushed off that heavy, unsettled feeling in your stomach, telling yourself it is stress, a late meal, or something you ate too quickly? When the discomfort passes, you assume it was nothing to worry about and get back to your day. But when the same discomfort starts showing up more often, even when nothing unusual has changed, it’s easy to wonder if your body is trying to tell you something.
Most of the time, it’s something simple, like reflux or gastritis. But sometimes, those lingering symptoms are linked to something that needs more attention, such as gastric cancer, which often develops slowly and can be difficult to detect in its early stages.
Dr Jenson, clinical oncologist, explains that gastric cancer can be difficult to detect early because symptoms often appear only in the later stages. This happens largely because early signs and symptoms are vague and easily mistaken for common digestive issues such as gastritis or acid reflux.
He notes that stomach or gastric cancer in Malaysia is not common, ranking only rank 11th among cancers reported by the World Health Organization’s Global Cancer Observatory, (2022). However, its clinical impact is disproportionate as patients often present late and outcomes continue to lag behind best-in-class benchmarks. The relatively low prevalence in Malaysia, limited public awareness, and lack of a national screening programme are all contributing factors,” he says.
In contrast, countries such as Japan, where gastric cancer is more common, have national screening initiatives that allow for earlier detection. “Here in Malaysia, colonoscopy screening is recommended from the age of 45. In most private hospitals, an upper endoscopy or oesophagogastroduodenoscopy (OGDS) is often performed together with the colonoscopy as part of a screening package to detect H. pylori infection and enable early eradication,” he adds.
When asked what warning signs people should look out for and how to differentiate them from less serious conditions, Dr Jenson highlights that certain warning signs which are persistent or progressively worsening should not be taken lightly.
Common warning signs include:
- Constant indigestion or dyspepsia: Burning or upper abdominal discomfort often mistaken for gastritis or acid reflux.
- Early satiety: Feeling full more quickly than before.
- Unexplained weight loss: Losing weight without trying.
- Loss of appetite, particularly a reduced desire for meat.
- Persistent nausea or vomiting: Vomiting blood or coffee-ground material is a red flag.
- Abdominal pain or bloating after meals.
- Difficulty swallowing (dysphagia): Particularly if the tumour is near the gastroesophageal junction.
- Signs of bleeding: Such as black stools, pale complexion, or feeling fatigue, which may indicate iron deficiency.
He advises, “If any of these symptoms are new, persistent, or accompanied by red flags as mentioned above, don’t delay seeking medical attention. Early diagnosis can make all the difference.”
Understanding the stomach and why it matters
The stomach isn’t just a container for food. It breaks down what you eat and prepares it for digestion and absorption. When its lining becomes irritated or damaged through infection, inflammation, or long-term habits, those changes can build up over time.
Gastric cancer develops when some of the stomach’s lining cells begin growing abnormally and form a tumour. It often progresses gradually, and the early stages can look like ordinary stomach issues that many people ignore or self-treat.
How infection can play a role
One of the most common causes of long-term stomach inflammation is a bacterium called Helicobacter pylori (H. pylori).
The infection is widespread and often causes no symptoms. However, in some people, it can lead to chronic inflammation or ulcers, and over many years, this irritation may increase the risk of developing more serious stomach problems.
In many parts of Asia, H. pylori infection and long-term stomach irritation are common, and both can increase the risk of gastric cancer if not treated. These changes usually develop slowly, which means there is often time to detect and manage them early when persistent symptoms are checked by a doctor.
Helicobacter pylori infection is a well-known risk factor for gastric cancer, and understanding the connection between the two can help people take preventive steps if diagnosed with the infection.
H. pylori is a type of bacteria that lives in the stomach lining and is very common worldwide, especially in Asia, where it’s often acquired during childhood. The World Health Organization classifies it as a Group 1 (definite) carcinogen. While many people with H. pylori infection don’t experience symptoms, in some individuals it can cause chronic inflammation of the stomach lining. Over time, if left untreated, this persistent inflammation can lead to changes in the stomach’s mucosal lining, increasing the risk of developing gastric cancer. H. pylori infection can also raise the risk of peptic ulcer disease, which affects the stomach and duodenum.
Detection tests for H. pylori can be broadly divided into non-invasive and invasive methods.
Non-invasive tests (preferred in low-risk cases without alarm symptoms):
- Urea breath test (UBT): Highly accurate, non-invasive, and considered the preferred screening method.
- Stool antigen test: Accurate and inexpensive.
- Serology test for H. pylori antibodies: Useful but unable to distinguish between past and current infection.
The urea breath test is the most accurate and commonly used non-invasive method, widely available in screening centres across Malaysia.
Invasive tests (performed during a gastroscopy or endoscopy procedure):
- Rapid urease test (RUT): A biopsy sample is placed on a test kit that gives near-instant results.
- Tissue histology: A biopsy sample is examined under a microscope by a pathologist.
- Culture of gastric biopsy: Technically demanding and not routinely performed.
The rapid urease test is the most common invasive method in Malaysia, typically done when patients are already undergoing endoscopy for concerning symptoms or visible ulcerated lesions.
If a person tests positive for H. pylori, treatment is straightforward and effective. A doctor will prescribe a course of antibiotics to eradicate the bacteria, which can significantly reduce the future risk of developing gastric cancer, especially if treatment occurs before any precancerous changes develop.
Everyday symptoms that deserve a second look
The early signs of gastric cancer often mimic common digestive complaints. What matters is how long they last and whether they’ve changed from what feels normal for you.
Here’s what to notice, and what it often feels like in everyday life:
Feeling full after only a few bites, even when you haven’t eaten much. For example, you start dinner but lose your appetite halfway through because your stomach feels heavy.
A burning or sour sensation in your chest or upper stomach after meals. It may fade with antacids but keeps coming back sooner or lasting longer.
A stretched, heavy feeling that lingers after eating. It isn’t sharp pain, more like a dull pressure that stays.
Food doesn’t appeal the way it used to, or you feel slightly queasy without a clear reason.
You notice your clothes fitting looser or that you tire more easily, even though your daily habits haven’t changed
These symptoms don’t always point to something serious, but if they last more than a couple of weeks or don’t ease despite resting, adjusting meals, or trying over-the-counter antacids, it’s best to have them checked by a doctor.
Who to see and what to expect
If you’re unsure where to start, visit your family doctor or GP. They can assess your symptoms, run initial tests, and refer you to a gastroenterologist, a specialist in stomach and digestive health, if needed.
During your first visit, your doctor may:
Test for H. pylori through a breath, stool, or blood test.
Review any medications that might irritate your stomach.
Suggest short-term treatment or diet adjustments to ease discomfort.
Arrange an endoscopy if symptoms persist or if there are warning signs.
If you don’t have a regular doctor, you can also visit a nearby clinic, where the doctor can assess your symptoms and advise whether further checks are needed. The key is to describe your symptoms clearly so your doctor can decide which checks are necessary.
How to describe your symptoms to your doctor
Being clear about what you are feeling helps your doctor see the full picture and understand what might be behind your symptoms. Here’s how to make your description more useful and less vague.
Share when you first noticed the problem and whether it has been getting worse. If your symptoms vary, mention how often they appear.
Use simple, familiar words instead of medical terms. You don’t need technical language; describe the sensation in a way that feels natural to you.
Mention any patterns you’ve noticed, such as when the discomfort tends to appear or what makes it better or worse. These details help your doctor narrow down possible causes.
Small changes in appetite, comfort, or energy might not seem important, but they can offer useful clues about your stomach health. Mention any differences in weight or daily stamina, even small ones.
Write down what you feel each day. It doesn’t need to be detailed; short notes on your phone or a notepad can help. Having a brief record makes it easier for your doctor to spot patterns and decide which tests might help.
You can note information like:
- The day and time symptoms appear
- What you ate or did before it started
- How it lasted
Before your appointment, sum up what you’ve noticed in one or two clear sentences. That short summary gives your doctor a clear starting point and makes the consultation more productive.
If you’ve noticed weight loss, mention it clearly to your doctor, including roughly how much and over what period, since they may ask. Specific details like this help doctors understand patterns and decide whether further checks are needed.
What happens during testing
If your doctor recommends further checks, you may be scheduled for an endoscopy. This is a procedure where a thin, flexible tube with a small camera is passed gently through your mouth into the stomach. It allows the doctor to see the stomach lining directly and check for inflammation, ulcers, or other changes.
If doctors notice anything unusual, small samples known as biopsies may be taken. These are painless and allow laboratory specialists to check for possible infection or irritation in the stomach lining.
Additional tests might also be suggested to give a more complete picture of your stomach health, such as:
Imaging scans like an ultrasound or CT scan to assess the stomach and nearby organs.
Blood tests to check for anaemia or other signs that may point to ongoing irritation or bleeding.
The results from these tests help your doctor identify not just common stomach issues but also early signs of more serious conditions, including gastric cancer. Sometimes, the findings reveal conditions that are manageable and respond well to early attention.
Dr Jenson explains that not all gastric cancers are the same, as some are more aggressive than others, and understanding the differences is crucial for determining treatment and prognosis. “Gastric cancer is not one single disease,” he says. “There are variations and distinctions that an oncologist needs to know in order to select the most appropriate treatment and predict disease outcomes.”
He adds that gastric cancers can be broadly divided into two main categories based on cell type, with additional distinctions made through molecular subtypes:
1. By cell type:- Intestinal-type gastric cancer: This type tends to grow more slowly, is more common in older individuals, and generally has a better prognosis, although stomach cancer remains a serious disease.
- Diffuse-type gastric cancer: This form is more aggressive, tends to spread earlier, and is often seen in younger patients. It can also occur in families. Because of its aggressive nature, oncologists usually adopt a more intensive treatment approach.
- EBV (Epstein–Barr virus)-related gastric cancer: May respond well to immunotherapy.
- Microsatellite instability-high (MSI-high): Often responds favourably to immunotherapy.
- Chromosomal instability (CIN): Frequently associated with HER2 positivity, which means the cancer respond to HER2-targeted therapies.
- Genomically stable gastric cancer (GS): Has fewer targeted therapy options and is typically treated with systemic chemotherapy.
According to Dr Jenson, identifying the cancer type helps oncologists in several key areas: prognosis, treatment planning, family screening, and follow-up care. More aggressive types, he explains, may require closer and longer-term monitoring to ensure timely intervention and better outcomes.
Understanding gastric cancer in context
Gastric cancer remains one of the more common cancers across Asia, especially in countries where H. pylori infection and diets high in salted or preserved foods are widespread. It often develops slowly and without clear symptoms, which is why many cases are only found at later stages.
The disease usually begins with long-term irritation in the stomach lining. This may come from an H. pylori infection, chronic inflammation, smoking, or frequent consumption of highly processed or salted foods. Over time, this ongoing irritation can gradually change the cells in the stomach lining, which may develop into more serious problems if not addressed.
What makes this important is that these changes don’t happen overnight. They build up gradually, which means there is time to act. Recognising lingering symptoms, testing for H. pylori, and addressing digestive issues early can help lower long-term risks.
Immunotherapy has emerged as a promising treatment in gastric cancer, marking a shift towards what is now known as precision oncology. This approach tailors treatment to the specific characteristics of each patient’s tumour rather than using a single standard method for everyone.
Immunotherapy, particularly drugs known as PD-1 inhibitors, is now a validated part of systemic treatment for both advanced gastric and gastroesophageal junction (GEJ) cancers, as well as in some curative settings. These treatments work by helping the body’s immune system recognise and attack cancer cells that would otherwise evade detection.
In gastric cancer, immunotherapy is not a one-size-fits-all treatment. It works best for certain tumour types that display specific biomarkers. To determine whether a patient is likely to benefit, the oncologist will need to run tests such as immunohistochemistry (IHC) and next-generation sequencing (NGS) on the tumour to check for features such as PD-L1, MSI (microsatellite instability), HER2, Claudin 18.2, and others. When these markers are present, combining immunotherapy with chemotherapy or other targeted treatments can improve response rates and survival outcomes.
In the initial, early treatment setting, the patients most likely to benefit from personalised targeted therapy include those with:
- PD-L1 high (CPS ≥5): Better outcomes when PD-1 immunotherapy is added to first-line chemotherapy
- HER2-positive and PD-L1 positive: May benefit from pembrolizumab (a type of immunotherapy) combined with trastuzumab (an anti-HER2 targeted therapy) and chemotherapy.
- MSI-high (Microsatellite Instability-High) or dMMR (Deficient Mismatch Repair): Strong likelihood of response to PD-1 inhibitors.
- CLDN 18.2: Benefit from Zolbetuximab (a type of monoclonal antibody) combined with chemotherapy.
Ongoing research continues to explore new treatment combinations, antibody–drug conjugates, and novel biomarkers that help to improve the survival outcome of gastric cancer. The field is advancing rapidly, and the outlook for gastric cancer treatment continues to grow more hopeful with each discovery.
Habits that protect stomach health
The stomach’s lining works constantly to digest food and protect itself from acid. Over time, repeated irritation from certain foods, infections, or habits can wear down these defences, which is why everyday choices matter
Practical steps that support stomach health include:
If you often eat preserved or spicy foods, try to balance them with fresh ingredients whenever possible. The mix of what you eat and how closely you listen to your body over time matters more than any single meal.
Dr Jenson shares that one of the biggest challenges for patients undergoing treatment for gastric cancer is maintaining proper nutrition. The disease itself, along with side effects from surgery, chemotherapy, radiotherapy, or immunotherapy, can make it difficult to eat well. “Weight loss and malnutrition are common, and both can weaken the body’s ability to tolerate treatment,” he explains. Because of this, early support from a dietitian can make a significant difference in recovery and overall wellbeing.
Eating can become challenging for many patients due to symptoms such as early fullness, loss of appetite, nausea, or changes in taste. Still, nutrition plays a crucial role in helping the body fight infection, maintain strength, and recover faster.
Patients are often encouraged to have small, frequent meals that are rich in protein and calories, such as eggs, fish, chicken, dairy products, nuts, and legumes. If solid food is difficult to manage, nutritious shakes or soups can be useful alternatives.
A dietitian can help customise meal plans to suit each person’s preferences and tolerance levels. Appetite may vary from day to day, but the goal is to keep a steady intake of nourishing foods, even in small amounts, to support the body’s recovery and energy throughout treatment.
Many people put off seeing a doctor for stomach issues, hoping things will settle on their own. That is understandable. Mild discomfort after certain meals or during stressful periods often does pass. But when something lingers, keeps coming back, or simply feels different from what is normal for you, it’s worth finding out why.
Seeing a doctor doesn’t always lead to bad news. For many, it brings relief, answers, and a plan to feel better sooner. And for some, it’s how small changes are managed before they become more serious.
Paying attention to what feels different isn’t about worrying more. It’s about understanding your body and taking the time to find out what’s behind those changes. Awareness like this can make a difference to your health over time.
This article was produced by Healthful For You. The views and opinions expressed throughout are those of the authors and do not necessarily reflect those of the Expert Contributor. The Expert Contributor has provided input solely for the EXPERT INSIGHT and TIP segments, based on their professional expertise. These comments are intended to offer general guidance and may not apply to all individuals. Any interpretations or conclusions beyond that section are those of Healthful For You. This article is not a substitute for personalised medical advice, diagnosis, or treatment. Please consult your doctor or a healthcare professional regarding your specific health needs.
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