Resection margin

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Schematic representation showing margin negative (A) and margin positive (B) excisions of a lesion. In a margin negative resection the lesion is completely removed; no lesional tissue is left behind in the patient. In a margin positive resection some lesional tissue is left behind in the patient.
Micrograph of a stained slide of a resected myopericytoma, the resection margin stained brown

A resection margin or surgical margin is the edge or "margin" of apparently non-tumorous tissue around a tumor that has been surgically removed, called "

pathologist to see if the margin is indeed free from tumor cells (called "negative"). If cancerous cells are found at the edges (called "positive") the operation is much less likely to achieve the desired results.[1]
: sections 1-2 

The size of the margin is an important issue in areas that are functionally important (i.e., large vessels like the

squamous cell carcinoma of the penis).[2] The desired size of margin around the tumour can vary. In resections for breast cancer, there appears to be a difference between European and American radiation oncologists, with the former preferring larger margins of over 5 mm.[1]
: section 2 

Micrograph showing a positive cauterized surgical margin in an adenocarcinoma (center-top of image). H&E stain.

Residual tumour at the primary site after treatment (it does not address the surgical margin as commonly believed) is classified by the pathologist as (AJCC 8th Edition):

  • R0 - no cancer cells seen microscopically at the primary tumour site.
  • R1 - cancer cells present microscopically at the primary tumour site.
  • R2 - Macroscopic residual tumour at primary cancer site or regional lymph nodes. It does not include metastatic disease identified but not sampled at the time of surgery.

The Margin Status following tumour resection (AJCC 8th Edition):

  • Negative margin: No tumour at the margin.
  • Microscopic positive margin: Tumour identified microscopically at the margin.
  • Macroscopic positive margin: Tumour identified grossly at the margin.
  • Margin not assessed.

Apart from traditional methods looking at stained "shaves" (thin slices of tissue removed from the edge of the margin) or smeared and stained imprints, more recent techniques used to assess margins include x-rays with compression, frozen specimens, and new techniques such as intraoperative fluorescence imaging, Raman spectroscopy, optical coherence tomography and quantitative diffuse reflectance spectroscopy.[3][1]: sections 5-6 

Definition

Edges and margins for an intestinal tumor.

Surgical margin in a surgery report defines the visible margin or free edge of "normal" tissue seen by the

false negative
error. A surgeon often will perform a second surgery if a narrow surgical margin is noted on a pathology report.

Associated errors and recurrence rate

This determination is made with the full understanding of "

CCPDMA methods, allowing the surgeon to routinely use very narrow surgical margins (1 to 2 mm for non-melanoma skin cancer).[7]
The worldwide extent of inadequate resection of the tumor is illustrated in following Table showing the percentage of positive surgical margins for the most common cancer types.

Percentage of positive surgical margins for the most common cancer types (estimated new cases worldwide, 2020) *Males and females combined [3]
Cancer type (solid tumours only) Estimated new cases * Incidence * Positive margins
Breast 2,261,419 12% 20–70%
Trachea, lung, and bronchus 2,206,771 11% 5–17%
Prostate 1,414,259 7% 7–75%
Colorectal 1,931,590 10% 12–58%
Urinary bladder 573,278 3% 0–25%
Kidney and renal pelvis 431,288 2% 7–11%
Uterine corpus 417,367 2% 4–17%
Pancreas 495,773 3% 18–85%
Thyroid 586,202 3% 10–11%
Lip, oral cavity 377,713 2% 5–43%

References

  1. ^
    PMID 23213495
    .
  2. ^ Sabatine M (2007). Sabatine's Essentials of Internal Medicine.
  3. ^
    PMID 35102436
    .
  4. ISBN 978-0-86542-299-5
    .
  5. PMID 26225798
    .
  6. ^ a b "Tri-Service General Hospital" (PDF). Archived from the original (PDF) on 2019-09-27. Retrieved 2018-03-17.
  7. ^
    S2CID 22275910
    .

Further reading
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