Objective: To determine the accuracy of naked eye assessment of surgical margins after formalin fixation in vulval cancer in comparison with microscopic assessment.
Design: Retrospective review.
Setting: The Gynaecological Cancer Centre, St Bartholomew's Hospital, London, U.K.
Population: Patients with primary vulval cancer who underwent surgery from 1997 to 2006.
Methods: Histopathology reports were reviewed and data on surgical margins were analysed. After formalin fixation, pathologists analysed surgical margins and measured them with a ruler. This measurement was compared with microscopic measurement. Other clinicopathologic variables were also recorded and compared.
Main outcome measure: Comparison between macroscopic and microscopic measurement, and the relation to clinicopathological variables.
Results: Naked eye assessment of surgical margins was within 2 mm of correlated microscopic measurement in 29 patients (Group 1). In ten patients the macroscopic measurement of clear margins was less than the microscopic (Group 2). In the remaining 11 cases (22%) naked eye observation overestimated the normal skin margins (Group 3). Seven patients from this group eventually fell into the unfavourable prognostic category of surgical margins <8 mm. The presence of LVSI was significantly more frequent in Group 3 than in the other two groups (p = 0.01). The difference between other variables of the study groups was statistically non-significant.
Conclusion: Our study demonstrates that naked eye assessment of surgical margins after formalin fixation is inaccurate and that surgical margins are often inadequate. We conclude that tumours with LVSI should be considered for a wider surgical excision.