In this interview by SADE OGUNTOLA, Dr. Omolade Adegoke, consultant pathologist, warns against overlooking persistent stomach complaints like indigestion and pain as they may be red flags also for stomach cancer commoners as people age.
What is stomach cancer and in comparison with other cancers, how common is it?
Stomach cancer is what medics call gastric cancer. It can occur in any part of the stomach.
Its incidence is much lower compared with say, breast cancer, the most common cancer in women or prostate cancer in men. However, the incidence of Gastric cancer is higher in westernized countries. But like many other cancers, even in Africa, its incidence appears to be rising. This could be because there is improvement in diagnosis and access to healthcare facilities.
Why do some individuals develop stomach cancer?
The risk factors associated with stomach cancer have been established. The most important is chronic gastritis, which is an inflammation in the stomach caused by bacteria called Helicobacter pylori. There is evidence that some individuals with Helicobacter pylori could develop gastric cancer.
In Africa, many people have been colonized by Helicobacter pylori when they are young due to poor hygiene and they do not develop stomach cancer. Some schools of thought call this the African enigma. The level of Helicobacter pylori infection in Africans does not directly collate with the incidence of gastric cancer, however, Helicobacter pylori is an established causative agent for gastric cancer.
Other risk factors for stomach cancer include toxins like nitrosamine present in smoked foods like fish, and suya, diets high in highly processed foods, red meat, cigarette smoking, alcohol and obesity. For instance, the incidence of stomach cancer in Japan and China is high because they eat a lot of smoked and salted foods. Japan carries out aggressive screening for stomach cancer; as such most cases are now diagnosed at a very early stage. It has also cut down on gastric cancer deaths.
In addition, some studies suggest that people with blood group A have a higher risk of developing gastric cancer. It suggested that people with blood type A have a poor immune response to Helicobacter pylori bacteria and therefore have an increased risk of stomach cancer. Also, some forms of gastric cancers are hereditary in western countries, although I have not seen much of this type here around Nigeria.
Do gastric cancer affect more men than women? Are there professional groups with a higher risk of developing this type of cancer?
Mostly gastric cancer has equal incidence in both genders; although established data from western countries indicate that it is usually a disease of the elderly. In developing countries, Nigeria inclusive, gastric cancer cases are seen more in middle age. You hardly ever see gastric cancer in the young or the very young.
Is gastric cancer, like breast cancer, with established screening methods to ensure they are detected early?
Unlike breast cancer or cervical cancer which can be screened for with breast mammography or a cervical pap smear or an HPV test, there is no cost-effective modality for gastric cancer. Upper gastrointestinal tract endoscopy is the main diagnostic tool for gastric cancer. It is a procedure in which a doctor uses an endoscope—a flexible tube with a camera to see the upper digestive system. But you cannot go on to do this for everybody; it is expensive and it is a bit invasive. But probably, it might be a good thing to incorporate that into medical check-ups after a particular age, particularly in those who have a family history of a hereditary type of gastric cancer.
Also, individuals with a family history of gastric cancer can undergo molecular tests to screen them for cancer at intervals. But the most important thing is for people to present early when they have symptoms.
So what are the symptoms of gastric cancer?
People would usually have symptoms like indigestion, nausea, vomiting, heartburn, sharp abdominal pain, and vague abdominal pain; unfortunately, these are symptoms that are not specific to gastric cancer. As a result, they resort to self-treatment using different over-the-counter medications when their symptoms persist.
Some people also have anaemia because they are bleeding in the gastrointestinal tract. The blood makes their stool very black and sticky. Even for people that present early to the hospital, because the symptoms are non-specific, the likelihood of sending them to have a GI endoscopy done on their first visit is low. They might just be advised on their diet and given medications to take care of their symptoms. However, when there is a high index of suspicion, this could be the savior.
Gastric cancer in one of our older medical textbooks is called “the captain of the men of death” because most people come late even in western countries because the symptoms are vague. Also, how soon the person comes may depend on where the tumour is in the stomach.
If it is at the outlet of the stomach, it will obstruct the stomach much more quickly as it starts to grow big. And then the patients will start to have problems like a bloated stomach, vomiting blood and throwing up stale food. This type of patient probably will come to the hospital early. But when cancer occurs in the mid portion of the stomach, it will take a long time before the obstruction occurs and then the symptoms become pronounced and the patient is rushed to the hospital and evaluated by a specialist.
Also, growth into the wall of the stomach can be a tumour and cause the wall of the stomach to harden up. Individuals with this will also come very late to the hospital to have investigations done.
The gold standard to make a diagnosis of stomach cancer is an upper GI endoscopy. The endoscopist may see a growth or an ulcer that can be malignant or a stomach wall that looks abnormal, they take a bit of it (biopsy) and send it for testing(histology) to give a diagnosis. Thereafter, the surgeons or oncologists will determine the best mode of treatment. Usually, the outcome of gastric cancer is all dependent on the stage of the disease, whether it is already spread to other parts of the body.
Is this the reason why many cases of stomach cancer in the community are assumed to be peptic ulcers?
Gastric ulcer and stomach cancer have similar symptoms. So, it is possible for the individual to just assume that it is a peptic ulcer. Also, they have similar risk factors-helicobacter pylori infect, alcohol ingestion and cigarette smoking. However, the symptoms are very similar until obstruction sets in. But through endoscopy, it is possible to tell if the obstruction is from a gastric ulcer or gastric cancer.
The gold standard to make a diagnosis is an upper GI endoscopy; if that is done, they see the mass or an ulcer which can be malignant or they see that the wall looks abnormal and they take a biopsy, send for histology to give a diagnosis. And then afterwards, you go to the surgeons or oncologists to determine the best mode of treatment.
Are there food items that are protective against gastric cancer?
Foods high in fibre like green leafy vegetables and fruits are protective from cancers that affect the intestinal tract, especially from the stomach. It is also advisable to cut down on the intake of red meat and refined carbohydrates, avoid smoked foods, minimize alcohol intake and avoid smoking. Antioxidants like Vitamin C can be of help generally in almost all cancers.
Is the survival rate from stomach cancer similar to say breast, cervical and prostate cancers, the top common cancers in Nigeria?
I wouldn’t say that its survival rate is lower, it all depends on the stage, when it is detected and treatment commenced. But the breast is on the surface, so the likelihood of detecting breast cancer is higher than say cancer in an internal organ such as the stomach. Also, the symptoms of gastric cancer can be very vague and as such, there is a tendency that people would have this for a long time and not come to the hospital.
So, what will be your advice for individuals with persistent peppery feelings in their stomach or indigestion?
They must rule out gastric cancer; with endoscopy, the gastroenterologist will be able to see exactly what the problem is, consider the changes in the lining of the stomach wall and understand why the individual’s symptoms persist. Of course, if Helicobacter pylori infection is detected, they are going to give the patient eradication therapy for the bacteria.
What will you recommend that the government and individuals do to reduce the incidence and deaths from stomach cancer?
Perhaps the best thing that the government can do is to make GI endoscopy both affordable and available. I am not sure how many state government hospitals have endoscopy suites although there are gastroenterologists in Nigeria who can carry out the procedure. An annual medical check is something that Nigerians should inculcate; they should walk in to have all the basic investigations. Those are ways that chances of early detection of any malignancy might be improved. Also, as much as possible try not to treat yourself if you have problems, especially when it’s persisting, rather go to the hospital.
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