Persistent indigestion or heartburn that does not clear up within three weeks is one of the earliest signs of stomach cancer, and it is also the one most often waved off as ordinary acid reflux.
The UK's National Health Service tells patients to see a doctor about digestive symptoms "not getting better after 3 weeks of using your usual treatments." That three-week benchmark is the point where common heartburn stops looking common.
The American Cancer Society lists heartburn and indigestion among the recognized symptoms of stomach cancer. Others include poor appetite, unintended weight loss, abdominal pain and feeling full after only a small meal.
Nausea, vomiting, and blood in the stool that can make it look dark brown or black round out the list. The society also stresses that early on, stomach cancer often causes no symptoms at all, which is a big reason the disease is frequently missed until it has already spread.
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Why the warning gets waved off
At MD Anderson Cancer Center, physicians note that early gastric cancer usually stays quiet, and that when signs do appear they can be "mistaken for less serious problems such as indigestion or heartburn."
Surgical oncologist Dr. Paul Mansfield tells patients that persistence is what should prompt a call to the doctor.
He advises that "anything that changes and persists is usually something to get checked out, especially if it lasts for more than two or three weeks."
Occasional heartburn after a heavy meal is common and rarely serious. Heartburn that keeps returning day after day, does not respond to over-the-counter antacids, or is paired with weight loss, trouble swallowing or dark stools deserves a doctor's attention.
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The numbers behind the urgency
The American Cancer Society projects about 31,510 new cases of stomach cancer in the United States in 2026 and roughly 10,740 deaths. The average age at diagnosis is 68, and six in ten patients are 65 or older.
Survival tracks closely with how early the cancer is caught. ACS figures show a five-year relative survival of 77 percent when the tumor is still confined to the stomach.
That drops to 37 percent once it has reached nearby tissue, and just 8 percent when it has spread to distant organs. Across all stages combined, the five-year figure sits at 38 percent, one of the lowest among major cancers, largely because most cases are found late.
What to do if your indigestion won't quit
If heartburn or indigestion is not clearing up on standard antacids after about three weeks, or if it comes with other warning signs, ask your doctor whether an upper endoscopy is appropriate. Welltica has previously covered additional early warning signs that most people attribute to ordinary digestion.
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Some readers already carry a higher baseline risk, including those with a long-standing H. pylori infection, a family history of gastric cancer or a history of chronic gastritis.
An upper endoscopy lets a gastroenterologist look directly at the stomach lining and biopsy any suspicious area, which remains the definitive way to catch stomach cancer at a stage when treatment still works best.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.