Surgical Margin Assessment Protocol (CAP)

Algorithm Steps

1. ▶

   Start

   Margin Assessment

   Systematic approach to surgical margins

   1. ●

      Action

      Specimen Orientation

      Essential for margin identification

      • Receive fresh or fixed with surgeon orientation
      • Document orienting sutures/clips
      • Photograph before sectioning
      • Correlate with surgeon operative note
      • Contact surgeon if orientation unclear
      1. ●

         Action

         Margin Inking

         Color-code margins

         • Use multiple colors for different margins
         • Document inking scheme
         • Let ink dry before sectioning
         • Consider agar to prevent smearing
         • Standard protocol: anterior, posterior, superior, etc.
         1. ●

            Action

            Margin Sampling

            Adequate representation

            • Perpendicular sections show true distance
            • Shave margins for large specimens
            • Sample closest margin to tumor
            • Additional sections if grossly close
            • Document sections submitted per margin
            1. ◆

               Decision

               Microscopic Evaluation

               Assess tumor to margin distance

               • Identify inked margin on slide
               • Measure tumor to margin (mm)
               • Note invasive vs in situ at margin
               • Assess for LVI near margin
               1. ⚠

                  Warning

                  Positive Margin

                  Tumor at inked surface

                  • Tumor cells touching ink
                  • Specify which margin(s) positive
                  • Note extent (focal vs extensive)
                  • Invasive vs in situ if applicable
                  • Clinical significance: re-excision often needed
                  1. ●

                     Action

                     Margin Reporting

                     Synoptic elements

                     • Status: Positive/Close/Negative
                     • Distance in mm for closest margin
                     • Which margin(s) involved
                     • Invasive vs in situ component
                     • Extent if positive (focal/extensive)
               2. ●

                  Action

                  Close Margin

                  Tumor near but not at margin

                  • Breast: <2mm often considered close
                  • Head/neck: <5mm often close
                  • Report exact distance in mm
                  • Site-specific and context-specific definitions
                  • May trigger re-excision or boost radiation
               3. ✓

                  Outcome

                  Negative Margin

                  Adequate clearance

                  • Tumor well away from inked surface
                  • Report distance to closest margin
                  • No re-excision typically needed
                  • Site-specific adequacy (1mm vs 10mm)
                  • Document which margins negative