Has the Whole Cancer Been Removed?

When cancer cells are removed from the breast, the surgeon tries to take out the whole cancer with an extra area or "margin" of normal tissue around it. This is to be sure that all of the cancer is removed.

The tissue around the very edge of what was removed is called the margin of resection. It is looked at very carefully to see if it is clear of cancer cells.

The pathologist also measures the distance between the cancer cells and the outer edge of the tissue.

Margins around a cancer are described in three ways:

• Negative: No cancer cells can be seen at the outer edge. Usually, no more surgery is needed.
• Positive: Cancer cells come right out to the edge of the tissue. More surgery may be needed.
• Close: Cancer cells are close to the edge of the tissue, but not right at the edge. More surgery may be needed.

Margins of resection

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