Evaluation of surgeons' marking of excision margins for superficial facial skin cancer lesions

Introduction: We established a series of exercises that evaluated surgeons' marking of excision margins, and we sought to identify factors influencing such marking. Methods: Twenty-four participants were asked to draw preset margins (3, 4, 5, 8 or 10 mm) on a series of life-size images representing noncosmetically and cosmetically sensitive facial sites, and also to draw circles of set diameters (3, 5 and 8 mm) on white paper. Margins were measured with vernier callipers calibrated to 0.05 mm. Results: In the small margin (3 mm) and noncosmetically sensitive exercises, the mean margins drawn were greater than required. When a 10 mm margin was required in cosmetically sensitive areas and nonsensitive areas, the margin was consistently underestimated in the former group by all participants (P < 0.05). Conclusion: Surgeons marking facial lesions for excision should use a measurement of scale, in order to eliminate the inherent tendency to underestimate the margin required for large excisions and for cosmetically sensitive areas.