Dr Ganesh Ramalingam: A blood test to detect gastric cancer? An endoscopy is still the way to go

One of the leading causes1 of cancer-related deaths is gastric cancer. This type of cancer may show little to no symptoms at all during its early stages – a reason why it becomes more difficult to treat when discovered at a later time. More than 300 lives succumb to gastric cancer yearly in Singapore, according to the Singapore Cancer Society.2

If you have been keeping up with the latest medical advancements, you may have heard about a recent “breakthrough” relating to gastric cancer detection. This new procedure (Gastroclear), as reported in an article published in The Straits Times,3 uses blood test kits to detect gastric cancer in its early stages. 

What do we know about this latest development?

As reported, this recent procedure is non-invasive as it would only require blood extraction. This is considered a huge plus-factor, especially for individuals who prefer not to undergo invasive medical examinations. Typically, gastric cancer detection is done through an endoscopy

Called Gastroclear, the test kits are also expected to cost less than $200 when purchased from a public hospital. This obviously makes it a cheaper and favorable alternative to endoscopy, which is an invasive procedure. An endoscopy procedure in Singapore can cost more than $800 without medical subsidy. 


Photo from The Straits Times

Is blood testing a better choice to detect gastric cancer than endoscopy?

If the factors that affect your decision in choosing a procedure for gastric cancer detection revolve around costs and the manner that it is done, you may lean more towards choosing a blood test instead of an endoscopy. 

However, as a doctor who has treated countless patients diagnosed with gastric cancer, I believe that the best and most accurate way to identify the existence of this kind of cancer is still an endoscopy

An endoscopy procedure enables a doctor to see the current condition of your upper digestive tract. Early gastric cancer symptoms, like tiny lesions, can be biopsied or treated outrightly with endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) when identified in the inner linings of your esophagus, stomach, or the upper portion of the small intestine. One study found out that these two procedures provide results comparable to surgery.4

On the other hand, initial findings show that a blood test can only tell of a certain percentage that a patient indeed has gastric cancer. It is NOT able to detect the onset of this disease. Likewise, a patient still has to go through an endoscopy procedure when the test result comes back positive. 

This actually happened to a cancer patient that sought treatment from my clinic. He had a blood test done and the result came out reporting that he had a low risk of getting cancer. The patient ended up needing to go through further tests and surgery for his treatment. Come to think of it, he had to spend twice when he could have saved on costs if an endoscopy procedure was done initially.

What I recommend for gastric cancer patients in Singapore 

My ultimate mission as a doctor is to always recommend the best treatments for my patients. As much as this recent non-invasive breakthrough in early detection of gastric cancer seems beneficial for patients who are not keen on getting invasive procedures, I cannot fully endorse this product.

Instead, here are my tips on how gastric cancer can be precisely detected early on:

Subject yourself to health screenings

Most of the diagnosed gastric cancer cases in Singapore are already found at an advanced stage. This happens because not everyone goes for regular health screenings. Getting screened is recommended for all -whether an individual exhibits symptoms of a certain disease or not- so make sure you subject yourself to one regularly. 

Be on the lookout for symptoms

Gastric cancer rarely displays symptoms. On the occasion that it does, you may observe these signs:

The symptoms above may also be caused by diseases other than gastric cancer. If you experience any of these and they worsen over time, it is crucial that you see a doctor for immediate evaluation.

Undergo an endoscopy

Endoscopy remains the gold standard procedure for detecting gastric cancer accurately as this involves biopsy and other techniques that can effectively treat early gastric cancer. Patients who have a moderate- to high-risk chance of getting gastric cancer are highly advised to undergo this procedure.5 


Can gastric cancer be prevented?

Prevention of gastric cancer is possible. Studies show that the avoidance of tobacco use lowers the risk of the body to develop various types of cancer. Likewise, dietary practices and restrictions, such as consumption of foods high in fiber (e.g. fruits and vegetables) and lowering your intake of red meat decreases the risk of gastric cancer development.6

You may refer to the Ministry of Health’s My Healthy Plate for a food guide. 

If you suspect that you or anyone you know may have gastric cancer, get yourself assessed by a gastroenterologist as soon as possible. Remember that later detection of this disease lowers the chances of a successful treatment. 


  1. Rawla, Prashanth, and Adam Barsouk. “Epidemiology of gastric cancer: global trends, risk factors and prevention.” Przeglad Gastroenterologiczny, vol. 14, no. 1, 2019, pp. 26-38, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6444111/.
  2. Singapore Cancer Society. “Stomach Cancer.” Singapore Cancer Society, 2016, https://www.singaporecancersociety.org.sg/learn-about-cancer/types-of-cancer/stomach-cancer.html. Accessed 20 November 2021.
  3. Tan, Cheryl. “Blood test for early detection of gastric cancer being evaluated for use in primary healthcare.” The Straits Times, 23 October 2020, https://www.straitstimes.com/singapore/blood-test-for-early-detection-of-gastric-cancer-being-evaluated-for-use-in-primary. Accessed 18 November 2021.
  4. Min, Yang Won, et al. “Endoscopic treatment for early gastric cancer.” World of Gastroenterology, vol. 20, no. 16, 2014, pp. 4566-4573. NCBI, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4000493/.
  5. Son Choi, Kui, and Mina Suh. “Screening for Gastric Cancer: The Usefulness of Endoscopy.” Clinical Endoscopy, vol. 47, no. 6, 2014, pp. 490-496. NCBI, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4260095/.
  6. Zali, Hakimeh, et al. “Gastric cancer: prevention, risk factors and treatment.” Gastroenterology and Hepatology from Bed to Bench, vol. 4, no. 4, 2011, pp. 175-185. NCBI, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4017429/.

This article was written and medically reviewed by Dr. Ganesh Ramalingam, M.D.