Clinical and histological findings in re-excision of incompletely excised cutaneous squamous cell carcinoma.

Background: Current guidelines mandate treatment of primary cutaneous squamous cell carcinoma (SCC) through to completion, including the demonstration of a margin of normal tissue, with surgical excision as the treatment of choice. Histologically incomplete excisions of all cutaneous SCC are preferably treated by surgical re-excision. The yield of performing further resection of scar tissue in patients with incompletely excised SCCs has not been previously evaluated.
Methods: A retrospective audit was conducted of 676 consecutive patients with surgically managed SCCs treated in our unit during 2005-2006.
Results: One hundred and nineteen (17.6%) tumours were incompletely excised, of which 84 underwent further excision. Routine histological examination revealed residual SCC in 24 (28.6%) of these specimens. Logistic regression analysis revealed tumour diameter and Breslow thickness to contribute independently to residual SCC (P<0.001). A lengthier delay between initial excision and re-excision predicted less residual tumour (P<0.005). Although the positive re-excision group tended towards a higher mean age (79+/-9 vs 74+/-12), with more head and neck lesions (79 vs 66%), logistic regression revealed no independent influence of age, gender, histological grade or anatomical site of the original lesion.
Conclusion: In our series, 28.6% of incompletely excised primary cutaneous SCCs showed residual tumour in re-excision specimens. Factors associated with residual tumour were similar to characteristics of high risk SCCs; larger lesions in particular are more likely to result in residual SCC at re-excision and may benefit from greater excision margins at the time of original resection. It is possible that regression of remaining tumour cells may contribute to our time-dependent findings and this warrants further research.