margin
Meaning of margin: Ink brushed onto the specimen is what keeps the true cut surface identifiable once the tissue has been sliced.
Definition of margin
A margin is the outer edge of tissue removed at surgery, the surface where the specimen was cut away from the body. A pathologist inks that surface, examines it under a microscope and reports whether cancer cells reach it. The answer is one of the main things that determines what, if anything, follows the operation.
What do the terms mean?
| Report says | What was seen | What it suggests |
|---|---|---|
| Negative, clear or uninvolved | No cancer cells touching the inked surface | The tumor was probably removed in full |
| Close | Cancer near the inked surface but not reaching it | Less reassuring; the distance considered adequate differs by cancer type |
| Positive or involved | Cancer cells at the inked surface | Disease may remain in the body at that point |
The word margin appears twice with different senses. During the operation the surgeon aims for a margin of normal tissue around the tumor, a physical clearance. Afterward the pathologist reports margin status, a finding. The second is a check on the first.
How is the edge actually assessed?
The specimen arrives whole and is painted with ink, sometimes several colors to record which surface faced which direction inside the body. Once the tissue is sliced, the ink is the only reliable sign of which cut was made by the surgeon and which by the laboratory. Sections are then cut and examined under a microscope. In some operations a frozen section is examined while the patient is still in theater, giving a quick answer that allows more tissue to be taken at once, though it is less accurate than the full processing that follows. Some skin cancer surgery goes further and examines essentially the entire margin layer by layer during the procedure.
Why does a clear margin not guarantee anything?
Standard sections sample only a fraction of the total surface, so a negative report means that cancer was not found where the tissue was examined. Some tumors also grow in scattered patches rather than as one mass, leaving islands beyond the visible edge. For that reason margin status is weighed alongside tumor size, grade, lymph node findings and molecular features rather than read alone, and it is one of several inputs into whether radiation, further surgery or closer follow up is discussed. What counts as an adequate clearance also varies between breast cancer, skin cancer and cancers of the digestive tract.
Used in a sentence
Pathology review of the surgical specimen reported clean margins with no cancer cells at the edge of the resected tissue.
Good to know
A negative margin reduces but does not eliminate the possibility that cancer cells remain beyond the tissue removed, since standard sections examine only part of the total cut surface.
Word origin
Where “margin” comes from
From Latin margo, marginis, meaning edge or border.