The short answer
After stomach surgery food reaches the intestine faster, which explains dumping syndrome, weight loss and poor absorption. If the upper part of the stomach was removed, vitamin B12 tablets are not absorbed and B12 is given by injection instead.
In a total gastrectomy the surgeon joins the esophagus straight to the small intestine, so food arrives faster and in a different state than before.
Nausea, diarrhoea, sweating and flushing soon after eating is dumping syndrome. Small portions every two to three hours and staying upright after meals are the usual first steps.
If the upper part of the stomach was removed, vitamin B12 tablets are not absorbed and B12 is given by injection, with regular blood work for vitamin and mineral levels.
The American Cancer Society describes visits every three to six months for the first few years, with an exam and symptom review, plus blood tests or upper endoscopy when ordered.
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The full explanation.
Eating after part or all of the stomach is gone
Stomach cancer surgery removes part of the stomach, or all of it. NCI describes both. In a total gastrectomy the surgeon joins the esophagus straight to the small intestine so you can still eat and swallow.
That plumbing explains almost everything that follows. Food arrives in the intestine faster and in a different state than before.
Ask which operation you had, and how much stomach is left.
The rush of symptoms after a meal
Nausea, diarrhoea, sweating and flushing soon after eating has a name. The American Cancer Society calls it dumping syndrome, and explains it as swallowed food passing quickly into the intestine.
It usually improves with time. Some people still need medicine for lasting diarrhoea.
Small portions eaten every two to three hours are the usual first step, along with staying upright after meals. Ask for a dietitian rather than working it out alone.
The vitamin problem
If the upper part of your stomach was removed, vitamin B12 in tablet form is not absorbed. The American Cancer Society says so directly, and describes B12 by injection instead.
It also says people who have had this surgery will probably need regular blood work to check vitamin and mineral levels.
Ask which levels are being checked, how often, and what a low result would feel like.
Weight, strength and feeding tubes
Weight loss is common enough to plan for rather than react to. Ask what weight you should report.
If eating cannot keep up, a tube into the small intestine can carry the load. It is placed through a small opening in the abdomen. Ask what would make your team suggest one, and what it takes to come off it.
How often the checks happen
The American Cancer Society describes follow-up visits every three to six months for the first few years, then less often.
Those visits include an exam and a review of symptoms. Blood tests and upper endoscopy may be ordered. Scans are not usually done at every visit, but they are done when something suspicious turns up.
Ask for your own schedule in writing.
If this cancer runs in your family
Some stomach cancers are inherited. Ask whether genetic testing applies to you, and what it would mean for your relatives.
Ask who in your family should be told, and who can help you tell them.
Questions for the follow-up visit
- Which operation did I have, and how much stomach is left?
- Will I need B12 injections, and for how long?
- Which vitamin and mineral levels are checked, and how often?
- What can I do about symptoms right after eating?
- Can I see a dietitian this month?
- How often will I have endoscopy or scans?
- Should my family have genetic counselling?
Related pages
Cancer Staging and Biomarker Testing explain the terms that show up in stomach cancer follow-up notes. Clinical Trial vs Standard Treatment, Palliative Care, and Questions to Ask Your Doctor cover what to raise at a stomach cancer survivorship visit.
Where this comes from
These questions were drawn from current patient guidance for stomach cancer:
Words to know
Tap any term to see what it means.
Common questions
Why do I feel awful right after eating?
That mix of nausea, diarrhoea, sweating and flushing is dumping syndrome, caused by swallowed food passing quickly into the intestine. It usually improves with time, though some people still need medicine for lasting diarrhoea.
Will I need B12 injections?
Probably, if the upper part of your stomach was removed, because B12 in tablet form is not absorbed then. The American Cancer Society says some people need vitamin supplements, which can include B12 injections. Ask which other vitamin and mineral levels are checked, how often, and what a low result would feel like.
What happens if I cannot eat enough?
A tube into the small intestine, placed through a small opening in the abdomen, can carry the load. Ask what would make your team suggest one, and what it takes to come off it.
Questions to ask your doctor
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Sources last checked: 2026-07-30 what this meansLast updated: 2026-08-18Next planned review: 2028-07-30
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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