Histologic safety margin in basal cell carcinoma of the eyelid: correlation with recurrence rate.

OBJECTIVE: To examine the correlation between the minimum histologic safety margin (HSM) and recurrence rate of periorbital basal cell carcinomas (BCC).

DESIGN: Cohort study.

PARTICIPANTS: One hundred one patients with 101 BCCs treated surgically between 1997 and 1999 at the eye hospital in Freiburg were enrolled in this study. Mean follow-up was 7 years (range, 104 days to 9.7 years).

METHODS: The tumors' minimum HSM was measured retrospectively in photographs of hematoxylin and eosin-stained paraffin slides using the digital picture analysis system AnalySIS of Soft Imaging System Inc, and/or calculated according to the tumor-free section number. Statistical analysis was performed using the Kaplan-Meier method and the log-rank test.

MAIN OUTCOME MEASURES: Histologic margins of solid and fibrous BCC and recurrence rate.

RESULTS: Seven of the 101 patients experienced tumor recurrence (6.93%) after a mean follow-up of 34.7 months (range, 3-83) according to Kaplan-Meier analysis. The patients were assigned to 1 of 3 groups: (I) those without HSM (n = 11), 3 recurrences (27.27%); (II) those with HSM <0.2 mm (n = 18), 3 recurrences (16.67%); and (III) those with HSM >0.2 mm (n = 72), 1 recurrence (1.39%). The difference in recurrences between those groups with HSM and HSM = 0, as well as between the HSM <0.2 mm-group and HSM >0.2 mm-group were statistically significant (P = 0.01; P = 0.03).

CONCLUSIONS: Extremely small HSMs are likely to prevent recurrences. At critical and visually easily accessible tumor sites (e.g., adjacent to the lacrimal puncta) a re-resection in solid BCCs with tumor-positive margins may not be mandatory, provided the surgical site is clinically inspected regularly. This conclusion does not apply to fibrous BCC.