Variables Affecting Basal Cell Carcinoma and Melanoma In Situ Excision Clearance: A Multi-institutional Retrospective Study

Abstract

BACKGROUND The primary endpoint for surgical excision of skin cancer is the positive margin status. Tumor characteristics may explain much of this risk, but other important factors can include physician specialty. OBJECTIVE To determine the variables affecting the success of a basal cell carcinoma (BCC) or melanoma in situ (MIS) excision. METHODS/MATERIALS An 8-year, multicenter, retrospective study of 5,800 BCC or MIS excisions performed at 13 different Kaiser Permanente medical centers. The margin status was determined by searching final pathology diagnosis texts for phrases associated with positive margins. RESULTS An incomplete excision rate was found in 23% of all specimens (BCC—22%, MIS—25%). Per specialty, the proportion of specimens with positive tumor margins was 24% for dermatology, 26% for plastic surgery, 28% for otolaryngology, and 12% for general surgery. General surgeons most often excised large tumors and tumors from truncal regions, 2 variables conferring lower odds of an incomplete excision. For non-Mohs procedures, dermatologists were no different than otolaryngologists or plastic surgeons in performing an incomplete BCC or MIS excision in all multivariate models (all p > .05). CONCLUSION Intrinsic tumor characteristics may influence the success of achieving tumor-free resection margins more than the specialty of the provider.

Clinicopathological Factors Associated with Incomplete Excision of High-risk Basal Cell Carcinoma

“…Furthermore, there was no difference in median tumour size between incompletely and completely excised tumours. These results are in line with previous studies where the same conclusion was reached ( 13 , 14 , 25 ). Nevertheless, these studies included all histopathological subtypes of BCCs.…”

“…The tumours of general surgeons and general practitioners were localized only on the face and scalp in 2% ( n = 2) and 18% ( n = 14) of cases, respectively, so it was deemed irrelevant to further analyse IERs for these physician specialties. Consistent results with no significant differences in IERs between different physician specialties have been observed in some studies ( 25 , 35 ). Although a few studies have shown that dermatologists have lower IERs than other physician specialties ( 11 , 17 ), the relevance of physician specialty when looking at IERs of aggressive BCC subtypes on the face and scalp is probably limited or non-existent and highly affected by confounding factors.…”

“…Several studies have compared the incomplete excision rates (IERs) for BCCs of any subtype in different settings, showing IERs ranging from approximately 5% to 24% ( 11 – 25 ). Some of these investigations also identified risk factors for incomplete excision, including: aggressive histopathological subtype; recurrent tumour; and localization on the nose, periorbital area, scalp and ears ( 12 – 14 , 26 ).…”

“…A few studies have observed higher IERs in BCCs with a diameter >20 mm ( 10 , 12 , 13 ) or <5 mm ( 14 ). Conflicting results have been reported regarding surgeon experience ( 13 , 15 , 16 , 25 ). A few studies show lower IERs for dermatologists ( 11 , 17 , 18 ) compared with other physician specialties.…”