Background
Basal cell carcinoma (BCC) is the most common malignancy in the white population. It is an important driver of healthcare costs and causes significant morbidity. Topical imiquimod is a good noninvasive treatment alternative for surgical excision in superficial BCC (sBCC). However, there are currently no uniform histological definitions of sBCC. A definition based on tumour thickness might be a good alternative.
Objectives
To determine whether tumour thickness in sBCC is a predictor of treatment failure.
Methods
We retrospectively examined 127 histological biopsy specimens of sBCC treated primarily with imiquimod five times a week for 6 weeks. Mean follow‐up was 34 months (range 3–91). Recurrence was evaluated clinically with histological verification.
Results
Among nonrecurrent cases the median tumour thickness was 0·26 mm (range 0·09–0·61), while for recurrent cases the median tumour thickness was 0·57 mm (range 0·41–1·41, P < 0·0001). Among lesions ≤ 0·40 mm in thickness, none recurred, whereas for lesions > 0·40 mm the recurrence rate was 58% (P < 0·0001).
Conclusions
We recommend the use of tumour thickness to define the superficial pattern in pathology reports for BCC as this can help to determine treatment response of sBCC to imiquimod.