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I live in Japan. Here, it is common for an annual health checkup to include a barium meal stomach x-ray, especially for people over 35, but sometimes younger.

A gastroenterologist told me that this is equivalent to about 20 normal x-rays, and is a completely unnecessary level of radiation exposure. He suggested an endoscopy was preferred if checking the inside of the stomach was required.

There are no exposure warnings that come with these checkups, and I understand Japan has higher than average stomach cancer rates due to a high-sodium diet (for example, this source says about 1 in 1000 tested are positive), but the same gastroenterologist also told me that Japan has abnormally high, but not well recorded, rates of cancer caused by diagnostic imaging itself.

Is an annual stomach x-ray an acceptable level of radiation exposure for a resident of Japan, considering the risk of stomach cancer?

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    How do you define "acceptable?"
    – Carey Gregory ♦
    Apr 2, 2019 at 15:02
  • I think Carey's point is quite important, and for medical purposes any diagnostic radiation has to be weighed against detection probabilities and resulting reductions in mortality/morbidity from early treatment, which in turn depends on individual risk factors, etc. xkcd.com/radiation is a great resource for radiation-based ballparking, though. In summary, this dose would be a measurable but small fraction of annual background radiation, and is much less than occupational exposure limits.
    – Bryan Krause ♦
    Apr 2, 2019 at 20:28
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    I think that's part of a question. Are the risks of the examination low enough to recommend it as part of an annual screening, compared to the risks of undetected stomach cancer?
    – Adam Millerchip
    Apr 3, 2019 at 0:57
  • Is refusing the exam or recommending others to refuse it sensible? The fact that is is included seems to mean that it recommended, but these are commercial operations that offer optional add-ons such as CT scans and even PET scans, so there is a profit motive that may be counter to the risk posed. I'd like to know the scientific basis.
    – Adam Millerchip
    Apr 3, 2019 at 1:03
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    I am assuming based on what you stated that it is a screening test for stomach cancer? I am not up to date on the meta-analyses or consensus reports for that screening, as it is not one of the standard screening tests recommended in the USA (which of course does NOT mean it has no utility in other populations). All cancer screening is a risk-benefit discussion that is best held with a physician who knows your risk factors. I did find this article, but it is just one study: ncbi.nlm.nih.gov/pubmed/29889263
    – DoctorWhom
    Apr 4, 2019 at 6:49

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Update version of the Japanese Guidelines for Gastric Cancer Screening (Japanese Journal of Clinical Oncology, 2018)

Radiographic screening is recommended for population-based and opportunistic screenings as its benefits outweigh its harms (Recommendation Grade B). Endoscopic screening is also recommended for population-based and opportunistic screenings as its benefits outweigh its harms (Recommendation Grade B). Both screenings are recommended to individuals aged 50 years and older.

These guidelines do not mention how often should the checkup be done, but another source recommends annual screening by gastroscopy only to people 70 years or older.

The optimal screening interval for gastric cancer using esophago-gastro-duodenoscopy in Japan (BMC Gastroenterology, 2012)

A screening for gastric cancer using esophago-gastro-duodenoscopy may be appropriate annually for healthy people over 70 years old, every two or three years for people 60–69 years old and every four years for people 50–59 years old. People younger than 50 years old may only need repeat screenings every five years or more.

BARIUM SWALLOW RADIATION EXPOSURE

Examples of radiation doses during various radiological investigations (See the table here: Mayo Clinic Proceedings, 2010):

  • Barium swallow: 1.5 mSv (which equals 6 months of radiation exposure from natural background)
  • Standard abdominal X-ray: 1.2 mSv
  • CT of the abdomen and pelvis: 10 mSv

So, barium swallow results in only slightly greater radiation exposure than a standard abdominal X-ray. Most experts estimate the risk of the test like this (hps.org):

Fluoroscopic studies such as esophagrams and swallow studies are very low-dose/low-risk procedures, where the little radiation exposure and resultant absorbed dose do not result in any risk when compared to the medical benefit of answering your physician's question concerning your health.

GASTRIC CANCER RISK FACTORS

According to one systematic review, PubMed, 2018), main risk factors for gastric cancer include:

  • Male sex, being East Asian, family history of gastric cancer
  • Age (only 10% of all gastric cancers develops before 45 and most of them between 60-80 years of age)
  • High consumption of salty or smoked food
  • Smoking, excessive alcohol drinking, lack of physical activity
  • Infection with H. pylori of the stomach, or Human papilloma virus

The frequency of tests for gastric cancer can be adjusted to risk factors in a particular person.

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  • The Mayo Clinic link says that a chest x-ray is 0.1 mSV, or 10 days of background radiation. The barium swallow is as you said, 1.5 mSV or 6 months of background radiation - that sounds quite different to "only slightly greater radiation exposure than a standard abdominal X-ray" to me, as it is 15 times higher. It seems like an abdominal x-ray is quite different to a chest x-ray, and that changes the comparison quite a lot. Anyway, thank you for the useful information.
    – Adam Millerchip
    Apr 10, 2019 at 22:02

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