Professional
Technical
IVT
R1 resection
Surgical resection with microscopic tumor involvement at the resection margin.
Full Definition
An R1 resection indicates that while the tumor has been grossly removed, microscopic examination reveals malignant cells at or within 1mm of the surgical margin. This finding significantly impacts prognosis and often necessitates additional treatment such as re-excision or adjuvant radiation therapy. R1 resections are distinguished from R0 (complete microscopic clearance) and R2 (gross residual disease) classifications in oncological surgery reporting.
Usage
Usage note: Always specify which margin is involved when reporting R1 status.
In Context
- "The pathology report confirmed an R1 resection with tumor cells identified at the deep margin." — Surgical pathology report
- "Given the R1 resection status, the multidisciplinary team recommended adjuvant radiation therapy." — Tumor board discussion
Also known as
microscopically positive margin
incomplete microscopic resection
Contrasted with
R0 resection
clear margins
Don't confuse with
R0 resection
R2 resection