Emperor Hirohito and Duodenal Cancer: Understanding a Rare Diagnosis

A rare diagnosis, reported plainly

UPI reported in January 1989 that Emperor Hirohito had died at the age of 87, and that doctors in Japan had diagnosed him with duodenal cancer. UPI described it as "a malignancy in the portion of the small intestine that connects to the stomach."

The report leaned on how uncommon this is. Using data from the International Agency for Research on Cancer, UPI put the rate among Japanese men at 0.6 cases per 100,000 between 1978 and 1981, and 0.2 per 100,000 among Japanese women.

Dr. Thomas Mack, a professor of preventive medicine at the University of Southern California and an editor of the agency's manual on worldwide cancer incidence, told UPI: "It is a rare type of cancer. We have no idea what causes it." He added that so few studies of its origins had been done that nothing stood out in the data.

That is the public record of his illness, and this article does not extend it. What follows is what is known about cancers of the small intestine.

Where the duodenum sits

The small intestine is a long tube that connects the stomach to the large intestine, folded many times to fit inside the abdomen. It has three sections. The duodenum comes first, immediately after the stomach. The jejunum is the middle. The ileum is the last stretch before the colon.

The duodenum is a busy junction. Bile from the liver and enzymes from the pancreas both enter here. A tumor in this small space can block the passage of food, obstruct the flow of bile, or both.

Five different cancers in one organ

NCI groups small intestine cancers into five types: adenocarcinoma, sarcoma, neuroendocrine tumors, gastrointestinal stromal tumors, and lymphoma.

Adenocarcinoma is the most common. It starts in the glandular cells lining the intestine, and NCI notes that most of these tumors occur in the part of the small intestine nearest the stomach, which is the duodenum. NCI's health-professional summary puts adenocarcinomas at 25 to 50 percent of primary malignant tumors here. About 20 percent are neuroendocrine tumors, which favor the ileum instead.

The small intestine makes up most of the length of the digestive tract, yet cancer here is uncommon. NCI reports it accounts for 3.8 percent of all digestive system cancers. The 14,450 new cases forecast for the United States in 2026 — 0.7 percent of new cancer diagnoses, alongside 2,170 deaths — is an American Cancer Society projection that SEER, the federal statistics program, publishes. The median age at diagnosis is 66.

Risk factors NCI lists are a high-fat diet, Crohn disease, celiac disease, and familial adenomatous polyposis, an inherited condition that causes many polyps to form.

The symptoms are ordinary

That is the difficulty with this cancer. NCI's list contains nothing that would alarm anyone on its own:

• Pain or cramps in the middle of the abdomen.
• Weight loss with no known reason.
• A lump in the abdomen.
• Blood in the stool.

A duodenal tumor can also cause vomiting, because it partially blocks the exit from the stomach, and it can turn the skin yellow if it presses on the bile duct.

When to get checked

Ask for an appointment if:

• Abdominal pain or cramping in the middle of your belly has continued for more than three weeks.
• You are losing weight without trying, especially more than about 5 percent of body weight over six months.
• You feel full or nauseated soon after starting a meal, or you are vomiting food eaten hours earlier.
• Stool is black and tarry, or there is visible blood, either of which needs assessment within days.
• You feel a lump in the abdomen.
• Your skin or the whites of your eyes have turned yellow, which warrants an appointment within days.

Two groups should have a lower threshold for raising symptoms. People with Crohn disease or celiac disease, and people with familial adenomatous polyposis, carry higher risk and should say so when they describe new digestive symptoms.

There is no screening test for small intestine cancer in people without symptoms, because the disease is far too uncommon for population screening to make sense.

How it is found

Blood chemistry studies and liver function tests come first, since abnormal liver numbers can be a sign that a tumor is affecting bile flow.

Looking inside requires endoscopy, and NCI describes three kinds. Upper endoscopy passes a thin lighted tube through the mouth to view the esophagus, stomach, and duodenum, and it can take tissue samples at the same time. This is the test that reaches a duodenal tumor directly.

The rest of the small intestine is harder to see. Capsule endoscopy uses a swallowed capsule the size of a large pill. It holds a light and a tiny wireless camera, and it sends pictures to a recorder worn on the body. It passes out naturally afterward. Double balloon endoscopy uses two nested tubes. A balloon anchors the scope while the outer tube advances, so a doctor can work along the intestine and take biopsies.

Staging uses the AJCC TNM system, and NCI notes a limitation worth knowing: that staging classification applies only to adenocarcinomas. Other tumor types are assigned TNM categories but not a stage grouping.

Treatment

NCI states that surgery is the most common treatment. The usual operation is a resection, which removes the affected segment with nearby tissue, and sometimes nearby organs if the cancer has spread. Radiation therapy and chemotherapy are the other standard options.

The health-professional summary is direct about the principle at work. As in other gastrointestinal cancers, surgery is the main approach when the tumor can be removed, and cure depends on whether it can be taken out completely.

What the numbers show

SEER reports five-year relative survival of 71.8 percent overall for small intestine cancer diagnosed between 2016 and 2022. By stage, it is 86.3 percent for localized disease, 79.6 percent for regional spread, and 47.9 percent when the cancer has reached distant organs. Cases split roughly into thirds, with 33 percent localized, 33 percent regional, and 27 percent distant at diagnosis.

Those figures pool five biologically different cancers under one heading, so they fit no single tumor type well. They are group statistics, and they describe no individual. They also come from a period nearly four decades after Hirohito's diagnosis.

Sources

• https://www.cancer.gov/types/small-intestine/hp/small-intestine-treatment-pdq
• https://www.cancer.gov/types/small-intestine/patient/small-intestine-treatment-pdq
• https://seer.cancer.gov/statfacts/html/smint.html
• https://www.upi.com/Archives/1989/01/06/Doctors-say-cancer-that-plagued-Hirohito-is-rare/7341600066000/
• https://www.cancer.org/research/cancer-facts-statistics.html