The safety margins for excision of basal cell carcinomas (BCC) have been reported but safety margins for tumors limited to the periocular area have not previously been specifically addressed. The authors of this study defined the histologic safety margins for periorbital BCC by following 101 patients for a mean of more than seven years after they underwent surgical treatment for BCC. They found that histologic safety margins of 0.2 mm were sufficient to prevent solid BCC recurrences. There were recurrences among 27 percent of patients without histologic safety margins, 17 percent with histologic safety margins of less than 0.2 mm and 1.4 percent with histologic safety margins of more than 0.2 mm.
In their report, the authors did not distinguish between the nodular and morphea forms of BCC, which have different clinical and histologic profiles. Nodular BCC has distinctive borders, while morphea BCC has indistinct clinical borders and tends to sprout or have distant nests of tumor cells. Therefore, it would be expected that histological safety margins would be larger for the latter type.
The authors addressed only the histologic margins and did not correlate them with clinical appearance and clinical margins. Normal-appearing clinical margins are usually larger than histologic-affected margins, and clinicians plan procedures according to the clinical margins unless performing Mohs' or another equivalent surgery.
The authors did not address the criteria or goals of the intended excisional biopsies or histological grading. They also did not report exclusion criteria for the study (beyond lack of consent to participate) nor whether any of the patients had previously undergone surgery. The range of follow-up periods, spanning from 104 days to 9.7 years, seems to be wide, and the standard deviation was not reported.
Additionally, the authors did not correlate outcomes with the tumor's initial size, depth or location, information that would provide clinicians with more tools with which to face periocular BCC. It is possible that larger and thicker tumors have a higher tendency to recur. Moreover, it is challenging to adequately handle small tumors/biopsies. Finally, the question remains whether there exists a difference in histologic safety margins in the periocular area compared with other parts of the body, and if so, how the existence of such a difference might be explained.
Dr. Rumelt has no financial interests to disclose.