Invasive vulvar carcinoma and the question of the surgical margin

ObjectiveTo assess the discrepancy between width of surgical margin measured with the naked eye/ruler by a surgeon before removing an invasive vulvar carcinoma, and width of margin measured under microscope by pathologist after fixation of the resected lesion with formalin. Potential relationships between discrepancy and disease recurrence were also investigated.MethodsThis prospective study was conducted with resected lesions from 86 women who underwent surgery for primary/recurrent invasive vulvar carcinoma. After the surgeon removed the lesions surrounded by 1–2-cm margins, the pathologist determined margin width at the 4 cardinal points of 86 lesions (for a total of 344 margin assessments), first macroscopically and then under the microscope.ResultsA safety margin of 0.8 cm on microscopic view was achieved in 83% of cases (112 of 135) when the macroscopic measurement was 1 cm, in 91% of cases (58 of 64) when it was 1.5 cm, and 98% of cases (105 of 107) when it was 2 cm.ConclusionThere was a small discrepancy between the surgeon's intent and the microscopic margin measurement, mostly related to tissue shrinkage. A 1-cm surgical margin corresponded to a 0.8-cm margin in microscopic view (the “safe margin”) in most cases.