The short answer
After surgery, a pathologist checks the edges of the removed tissue. A "negative" or "clear" margin means no cancer cells were seen at the edge — a reassuring result. A "close" margin means cancer came near the edge but didn't reach it; whether that's close enough to act on depends on the cancer type. Neither result decides your outcome alone, and the definition of an acceptable margin varies by cancer.
Negative (clear) margin: no cancer cells at the cut edge — generally reassuring.
Close margin: cancer is near the edge but not touching it; significance depends on the cancer type.
There is no single "safe" distance across all cancers — standards differ.
Margins are one factor among grade, stage, and biomarkers.
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The full explanation.
What a margin is
When a surgeon removes a tumor, they take out the tumor itself. They also take a rim of normal-looking tissue around it, called the margin. A pathologist then examines that rim under a microscope. They check whether cancer cells reach all the way to its outer edge. This tells your team whether the surgery likely got all the cancer. It also flags whether some may have been left behind.
Negative, positive, and close
A negative margin means no cancer cells are found at the outer edge of the removed tissue. This is the goal of most cancer surgery. It generally means the cancer was fully removed, as far as the pathologist can tell.
A positive margin means cancer cells are found right at the edge. This suggests cancer may still be present in the body, just beyond where the surgeon stopped cutting. A positive margin usually means more treatment is needed. That could mean more surgery to remove additional tissue, called re-excision. It could mean radiation aimed at the area instead.
A close margin sits in between. Cancer cells are near the edge but do not actually touch it. There is no single universal distance that defines "close." It depends on the type of cancer. Different cancers use different thresholds, sometimes just a millimeter or two. A close margin raises more concern than a comfortably negative one. It raises less concern than a positive one, though. Whether it needs more treatment depends heavily on your specific cancer type.
Why there is no single rule for every cancer
You might expect a fixed number, like "2 millimeters is always enough." That is not how it works. The safe margin distance differs by cancer type, tumor behavior, and location. A margin considered adequate for one cancer might be considered too close for a different, more aggressive cancer type. This is why your surgeon and pathologist interpret your specific margin result using standards developed for your specific cancer. There is no single universal rule.
What margin status changes about your plan
Margin status is one of the most direct, practical results in cancer care. It often changes what happens next, in a concrete way. A clearly negative margin, combined with other favorable features, may mean no further local treatment is needed. A positive or close margin often changes the plan directly. Sometimes that means more surgery. Sometimes it means adding radiation, to lower the risk that any remaining cells cause a recurrence in that same spot.
What margin status does not tell you
A negative margin is reassuring, but it is not an absolute guarantee. Cancer cells too small or too few to reach the sampled edge can still exist nearby. Even careful pathology can miss them. Margin status also does not tell you whether cancer has spread elsewhere in the body. It only speaks to the specific area that was surgically removed.
What to ask your team
- Was my margin negative, close, or positive, and what specific distance was found?
- What is considered an adequate margin for my specific type of cancer?
- Does my margin status mean I need more surgery, radiation, or neither?
- How does my margin status affect my risk of local recurrence?
Sources
Words to know
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Common questions
How wide does a clear margin need to be?
It depends on the cancer. For some cancers 'no ink on tumor' is enough; others aim for several millimeters. Your care team applies the standard for your specific cancer.
Is a close margin treated like a positive margin?
Sometimes. Depending on the cancer and location, a close margin may lead to more surgery, radiation, or simply closer monitoring. Your team will explain which applies to you.
Questions to ask your doctor
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Last updated: 2026-08-05Next planned review: 2027-07-12
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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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