Most of us know the feeling of a late dinner sitting heavy, or a flare of heartburn after too much coffee. You reach for an antacid and get on with the day. For some people, the same complaints are the body's first quiet warning of something more serious.
The American Cancer Society says early stomach cancer often causes no symptoms at all, or symptoms that look identical to everyday indigestion, nausea or heartburn. That overlap is one reason the disease is so often caught late.
Caught while the cancer is still inside the stomach, around three out of four patients live at least five years. Once it has reached distant organs, fewer than one in ten do.
| Stage at diagnosis | 5-year survival |
|---|---|
| Still in the stomach | 77% |
| Spread to nearby tissue or nodes | 37% |
| Spread to distant organs | 8% |
Those ACS figures cover patients diagnosed between 2015 and 2021. The National Cancer Institute flags a similar set of early signs. Neither authority uses them to diagnose anyone, but both urge readers to see a doctor when complaints keep coming back or get worse.
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When indigestion earns a closer look
The point is not that your heartburn is cancer. It is that a handful of symptoms, especially when they persist for weeks or show up together, deserve more than another antacid. Welltica has covered the same territory in a piece on indigestion lasting more than three weeks.
Here are the eight signs the ACS and NCI flag.
The 8 warning signs to know
1. Heartburn or indigestion that will not settle. Occasional reflux is common. The warning sign is heartburn or indigestion that keeps returning, or that stops responding to over-the-counter antacids.
2. Nausea or vomiting with no clear cause. Both authorities list ongoing nausea as an early sign. Vomiting with blood, even small amounts that look like coffee grounds, needs urgent medical attention.
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3. Feeling full after only a small meal. A sudden change in how much food fits comfortably in your stomach, known as early satiety, is one of the more specific signs on the list.
4. Loss of appetite. Not just "not hungry today" but a lasting drop in how much food appeals to you. The ACS lists poor appetite among the most common complaints at diagnosis.
5. Weight loss without trying. Dropping pounds without changing diet or exercise is one of the clearest red flags. Unintentional weight loss paired with any of the digestive symptoms above is reason enough to call your doctor.
6. Dark or tarry stools, or blood in the stool. Slow bleeding from a tumor can make stools look dark brown or black. It can also leave you tired and weak from a low red blood cell count, what doctors call anemia.
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7. Trouble swallowing. Food catching or feeling stuck going down, especially solid foods, can point to a tumor near the top of the stomach, where it meets the food pipe.
8. Ongoing pain in the upper belly. Vague discomfort above the navel is on the ACS list. A persistent, dull ache in that area, rather than a one-off cramp, is the pattern to watch.
Why so many cases slip through
Early stomach cancer usually has no symptoms, which is one of the reasons it is hard to catch, the NCI notes. By the time complaints start, the cancer has often already spread. That is exactly why doctors stress the word persistent.
A single bad night of reflux after a heavy meal is not a warning sign. Symptoms that last three or more weeks, or keep coming back, are.
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Risk is not evenly spread. The ACS notes that most people diagnosed with stomach cancer are in their 60s, 70s, or 80s, and that men are diagnosed more often than women.
A first-degree relative with the disease, and a long-standing Helicobacter pylori infection, also push baseline risk higher.
Everyday reflux is worth taking seriously in its own right. Welltica has previously covered everyday foods that quietly worsen acid reflux and GERD, which can mimic the same early picture.
The practical takeaway from both the ACS and the NCI is narrow. None of these eight signs on its own means cancer. But any one of them that lasts more than three weeks, or gets worse, or shows up with another on the list, is a reason to book a primary care visit.
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From there, an endoscopy can usually settle the question.
This article is made and published by Mie Hermansen, who may have used AI in the preparation.