On a biopsy report
Positive margin (R1 resection)
Also written as Margin involved, Margin positive, Involved margins, Cut through tumour, R1 resection
What it means
The margin is the edge of the tissue removed in surgery. A positive or involved margin means the pathologist found cancer cells at the edge. This suggests some cancer may not have been removed.
Why it matters
Your surgeon and oncologist decide whether more surgery or other treatment is needed.
Ask your oncologist
"My margin is positive. What are the next steps you suggest?"
From NCI Dictionary of Cancer Terms: margin. Not medical advice: your oncologist decides.