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

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

Cohort study.

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).

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.

Histologic margins of solid and fibrous BCC and recurrence rate.

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).

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.