JMT: Pathogenesis of gastric cancer and related treatment in Japan

JMT: Pathogenesis of gastric cancer and related treatment in Japan.  Gastric cancer is diagnosed in Japan and the usual treatment methods.

According to statistics on cancer deaths conducted by the National Cancer Research Center of Japan, 372,986 men and women died of cancer in 2016. Among them, 45,531 people died from gastric cancer (29,854 men and 15,677 women). In terms of the number of cancer patients in 2014, among men, gastric cancer ranked first, followed by lung cancer, which ranked second, and colorectal cancer, third.

Also in women, breast cancer ranks second, followed by colorectal cancer, and gastric cancer is the third. In addition, gastric cancer in men ranked second only to lung cancer in the site where the number of deaths was high in 2016. Similarly, women’s gastric cancer ranks fourth after colorectal cancer, lung cancer, and pancreatic cancer. (The above data comes from the Cancer Information Service “Cancer Registration and Statistics” of the National Cancer Research Center).

From the 5-year relative survival rate of each disease site (diagnosed cases from 2006 to 2008), it is 65.3% for men and 63.0% for women. The 5-year survival rate for gastric cancer is relatively high. When the cancer is diagnosed in a localized state, the 5-year survival rate is 95.9%. (The above is taken from the 2006-2008 Survival Rate Report of National Cancer Patient Monitoring Statistics (National Cancer Research Center Cancer Countermeasure Information Center, National Research and Development Corporation, 2016)).

What is stomach cancer?

Gastric cancer is a cancer formed by cells in the innermost mucosa of the stomach wall that become cancerous cells for some reason and proliferate repeatedly in disorder. It is said that it takes several years to reach the size that can be found in gastric cancer examinations. Over time, cancer cells will enter the stomach wall, spread to the outer serous membrane or even more outside, and also spread to the nearby large intestine and pancreas. Cancer spreading like this is called invasion.

Cancer cells move to other places along with the flow of lymph and blood, where they multiply. This is called transfer. The most common gastric cancer metastasis is “lymph node metastasis”, which proliferates in “lymph nodes” like lymphatic checkpoints. This also happens in early cancer. In addition, part of the advanced cancer also has metastases in the peritoneum and liver.

As a special type of gastric cancer, there is “scleros gastric cancer” that spreads in the stomach wall but does not appear on the mucosal surface. It is said to account for about 10% of gastric cancer. In the case of sclerogastric cancer, 60% of patients are found to have metastases at the time of diagnosis. The symptoms are also nothing special, and are similar to those of ordinary stomach cancer. But there are also patients who complained that the initial symptoms were back pain (radial pain). However, sclerogastric cancer rarely appears on the surface of the gastric mucosa and infiltrates like it penetrates into the stomach wall. It is difficult to find through an endoscope, and it is not rare that it has deteriorated when it is discovered. Therefore, there are symptoms of gastric cancer, but no abnormalities are found during the examination, and there are also many cases that are found after the development.

In the early stage of gastric cancer, there are few conscious symptoms, which have nothing to do with the development of gastric cancer, and there are cases where there are no symptoms at all. On the contrary, there are also cases of stomach pain, heartburn, and melena from the early stage. But these symptoms can also appear in symptoms such as gastritis and gastric ulcers. Therefore, it is often considered that it is not gastric cancer, but other diseases of the stomach. Needless to say, regular check-ups, as soon as the symptoms persist, it is related to the early detection of gastric cancer.

With the advancement of diagnosis and treatment, gastric cancer is considered to be one of the more easily cured cancers. The treatment of gastric cancer is determined based on the size and spread of gastric cancer. However, if it is discovered only when it is progressing, treatment is also difficult.

The tendency to suffer from gastric cancer becomes more obvious after the age of 40. The overall number of people suffering from gastric cancer has remained the same due to aging. However, compared with people in the same era, both men and women have dropped significantly. In terms of the number of deaths due to cancer, men ranked second in 2004 and women ranked first, but statistically, the death rate is decreasing.

Symptoms of stomach cancer

It is said that the symptoms of stomach cancer are very rare in the early stage, and even if it progresses, there may be no symptoms in some cases. Since the initial symptoms are similar to gastric ulcer and gastritis, when gastric cancer is not found, it is often regarded as an upset stomach. That’s because gastric cancer is in the disease stage classification at this time, which is equivalent to the “stage IA” of the early stage of gastric cancer. The cancer still stays in the gastric mucosa/submucosa. The surface of the stomach is mucosa, and the stomach itself has not been seriously damaged, so Symptoms appear. However, depending on the cancer and other parts of the cardia of the stomach, at this time, because the food stays in the stomach, the stomach will feel uncomfortable and dull.

The symptoms of early gastric cancer are as follows.

• Indigestion and stomach upset
• Swelling after a meal
• Mild nausea
• Low appetite
• Heartburn

If stomach cancer worsens, the following symptoms will appear.

● Loss of appetite, nausea and vomiting

If stomach cancer narrows the digestive tract, the passage of food becomes worse and the stomach becomes heavy. Therefore, sometimes you lose your appetite or the feeling of vomiting.

● Thinness and fatigue

Loss of appetite and nausea and vomiting make the body unable to absorb nutrients, resulting in weight loss and general fatigue.

● Hematemesis, blood in stool

Cancer causes stomach cells to collapse and bleed, expelling the blood accumulated in the stomach from the body. If it is blood in the stool, since stomach acid will oxidize the blood, you will see black stool in many cases.

● Abdominal pain, abdominal discomfort

Pain in the heart cavity and belly button, or dull pain and dull pain in the abdomen before and after eating. Although it is not a specific symptom of gastric cancer, it is a symptom that many patients with gastric cancer will experience.

● Heartburn

This is a symptom that may occur when cancer appears on the border of the esophagus and stomach. Food does not flow smoothly, which will make people feel that food is overstocked after meals, and food will also accumulate. This symptom is also common in the case of reflux esophagitis.

In addition, with the development of gastric cancer, there will be jaundice in which the skin and whites of the eyes turn yellow, ascites accumulated in the abdominal cavity, and dysphagia that makes it difficult to swallow food.

Of course, not all symptoms are suitable for everyone.

Causes of stomach cancer

Many studies have been conducted on the causes of gastric cancer, and several risk factors have been known. The risk factor mentioned in particular is Helicobacter pylori infection. WHO has also identified it as a real carcinogen.

When Helicobacter pylori infects the gastric mucosa, the surface layer of the stomach can cause gastritis. If you are continuously infected by Helicobacter pylori, the gastric mucosa will become chronic gastritis and the gastric mucosa will gradually shrink. As a result, the process of canceration of the cells forming the stomach wall is accelerated, which is considered to be the cause of gastric cancer.

A study investigating the incidence of gastric cancer between Helicobacter pylori-negative people and Helicobacter pylori-positive people has the following results.

● People who are negative for Helicobacter pylori: No one has stomach cancer 10 years after starting the study

● People who are positive for Helicobacter pylori: About 10 years after the start of the study (average follow-up time 7.8 years), 2.9% of people had stomach cancer and received treatment.

In other words, 1 out of 34 people infected with Helicobacter pylori has become gastric cancer, and the risk of gastric cancer is not low.

Risk factors for gastric cancer also include disorders of eating habits and lifestyle habits, such as excessive intake of salty foods and smoked foods, insufficient intake of vegetables and fruits, drinking, smoking, and foods that are not in good practical storage conditions. In addition, the elderly and men, people with chronic gastritis and gastric polyps, and people with gastric cancer among blood related people have a high risk of gastric cancer.

Gastric cancer examination and expenses

Cancer screening is not just for the purpose of “detecting cancer” by being tested. There is also the purpose of “reducing cancer deaths through examinations, early detection of cancer and appropriate treatment.” Stomach cancer screening is the earliest cancer screening in Japan. It started with uterine cancer screening in 1983.

Examination methods for gastric cancer: consultation, gastric X-ray examination and gastric endoscopy

Target person: Over 50 years old　※1

Interval of consultation: once every two years　※2

※1: At present, regarding gastric X-ray, it is also possible to perform examinations over 40 years old

※2: At present, regarding gastric X-ray, it is possible to perform an examination once a year

After the start of the gastric cancer examination, a “gastric X-ray examination” was performed as an examination item, and the target was 40 years old and above. However, with the recent development and advancement of medical technology and medical equipment, “stomach endoscopy” has been added to the items of gastric cancer screening since 2016, and the age of the subject has also changed. Those who have undergone “stomach X-ray examination” are for those over 40 years old, and those who have undergone “stomach endoscopy” are for those over 50 years old.

In addition, according to recent studies, it has been found that the infection of “Helicobacter pylori” is related to the onset of stomach cancer in the future. In addition, in the pre-onset stage of gastric cancer, there are chronic gastritis and “atrophic gastritis” of gastric mucosal atrophy. If there is atrophic gastritis, the substance called “pro-gastroprion” in the blood will decrease, so the state of gastritis can be estimated based on the test value.

At present, although it is not necessary as an item of gastric cancer examination, depending on the medical institution that undergoes gastric cancer examination, there are also “Helicobacter pylori antibody test” and “gastric proenzyme test”.

Stomach X-ray

Stomach X-ray is a method that uses X-rays to check the internal state of the stomach. As a cancer screening, it is an effectiveness test approved by the Ministry of Health, Labour and Welfare. The dinner on the day before the test and the breakfast on the day of the test cannot be eaten. In order to check the internal condition of the stomach, you need to take the contrast agent barium and the carbon dioxide foaming agent that swells the stomach in the institution under the test.

The examination is performed on a rotating table, rotating the body according to the instructions, so that the entire stomach is attached with barium before taking pictures. After the end, take a laxative to completely excrete the barium from the body.

Stomach X-ray examination, although there is a certain degree of unevenness due to radiation and examination accuracy, but the cost is cheap, the examination is less painful, and people who do not want to spend money on gastric examinations have not had stomach problems until now. It is recommended for people who do not have stomach pain and are under 40 years old.

In the case of a medical examination, the cost is about 3,000 yen at a medical institution, and it is about 1,500 yen in most cases conducted by local governments such as health and welfare centers.

Gastric endoscopy

Gastroscopy is an inspection method in which a small camera is inserted from the mouth or nose to directly observe the inside of the stomach. It has been popularized as an optional diagnosis for a long time. However, after the “Guidelines for the Implementation of Cancer Diagnosis” were revised in 2016, it was implemented as a countermeasure diagnosis of gastric cancer. Stomach endoscopy can clearly see the tiny changes in the mucous membrane. If a suspected lesion is found, the tissue can be taken at the same time, and a detailed examination can be performed with a microscope.

Endoscopy also requires fasting the night before and the morning of the examination day, and taking medicines that distend the stomach in the hospital for examination. Because anesthesia and sedatives can be used for the examination, general anesthesia and local anesthesia of the larynx can be selected depending on the institution that performs the examination.

Stomach endoscopy can detect gastric cancer earlier than X-ray examination of the stomach with barium. On the other hand, there may be differences depending on the skills of the doctor doing the examination.

Recommended crowd for this check

●Those who want to thoroughly investigate the stomach

●Persons with family history of gastric cancer

●People with symptoms such as loss of appetite

●Persons with Helicobacter pylori infection in the past, or those who have been sterilized by Helicobacter pylori

If you only do gastric endoscopy, the cost is about 3,000 yen, but if abnormal tissue is found for sampling and biopsy, the cost is about 8,000 yen to 10,000 yen. The amount varies from hospital to hospital.

In addition, if the gastric endoscopy is performed during the physical examination, even if the same examination is received, insurance is not applied, and medical treatment is at your own expense. However, because of the results of the physical examination, it is recommended to undergo endoscopy, re-examination, and close examination. Insurance is applicable. If you are accepted as a cancer diagnosis, if you do not have a biopsy but only an examination, then insurance is applicable.

Gastric prion test, Helicobacter pylori antibody test

There are also gastric proenzyme test, Helicobacter pylori antibody test, etc., and there are parallel tests.

The so-called pro-gastric prion test is to determine whether there is atrophic gastritis by drawing blood before gastric cancer occurs. The test is cheaper and less burdensome. On the other hand, the results of the test may not be related to gastric cancer, and there are cases where a negative diagnosis is actually gastric cancer.

The Helicobacter pylori antibody test is to find Helicobacter pylori that is related to gastric cancer. The inspection fee is cheap, and the inspection method is “breathing into a special bag”, which is a relatively small inspection on the body. On the other hand, even if it is confirmed to be infected with Helicobacter pylori, it is not necessarily 100% of gastric cancer, so it cannot be used as an inspection item for close examination.

Examination and diagnosis of gastric cancer

When gastric cancer is suspected, perform gastric endoscopy or gastric x-ray examination. Examinations for the spread of gastric cancer include chest X-ray, abdominal ultrasound (echo), CT, rectal examination, etc.

Stomach Ⅹ line examination (barium examination)

Drink the barium and observe the shape of the stomach and the state of the mucous membrane (folds) with X-rays. Drink the foaming agent to expand the stomach. In order to make the barium adhere to the gastric mucosa, the body rotates up or down on the stomach.

It is easy to hiccup if you drink foaming agent, but you need to be patient in order to make the stomach easier to see during the examination. It is said that the sensitivity of the test is 70 to 80%, which is a better test for early detection of gastric cancer.

Endoscopy

It is an examination to directly observe the inside of the stomach with a fiber endoscope to investigate the spread and depth of the suspected cancer site. It was previously called a gastroscope. Part of the tissue from the area suspected of being cancer can be examined by pathology to investigate the presence of cancer cells. Put the camera directly into the stomach, you can clearly see the small changes in the mucous membrane, and you can easily check the lesions and bleeding with less bumps.

In addition, when a gastric X-ray finds a suspected lesion, endoscopy is also performed as a definitive diagnosis.

There are also ultrasound endoscopy and ultrasound examinations that are performed with an endoscope with ultrasound function. This is used to investigate the deep diagnosis and progression of the lesion.

Rectal examination

Inject barium and air from the anus, and check the shape of the large intestine with X-ray. Check the large intestine near the stomach for cancer spreading, peritoneal metastasis, etc. If air enters the large intestine during the examination, a tightness in the lower abdomen will be felt strongly.

Disclaimer:

This article is summarized by Japan Medical Tourism Corporation, but it is not intended as the ultimate cancer treatment plan for individual patients. Do not treat yourself. For treatment of illness, please follow your doctor’s plan or go to Japan for treatment.

(source:internet, reference only)

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