Background: Wound healing following a partial biopsy of basal cell (BCC) and squamous cell carcinomas (SCC) may induce tumor regression.
Methods: Nonmelanoma skin cancer (NMSC) biopsy and re-excision specimens from 1994 to 2001 were reviewed for histologic evidence of scar vs. presence of residual tumor in excision specimens. Regressed and non-regressed tumors were analyzed to assess the influence of anatomic location, biopsy technique (punch vs. shave), histologic subtype of BCC or SCC, time interval between biopsy and excision, and patient age.
Results: Nine hundred and ten excisions were performed for transected BCC or SCC, 217 (24%) of which showed scar with no residual tumor. Logistic regression analysis revealed significant differences in the regressed vs. non-regressed subsets. SCCs were more likely to regress than BCCs (40% vs. 20%, respectively, p < 0.00001). Independent of the NMSC type, tumors regressed more often following shave rather than punch biopsy (34% vs. 15%, respectively, p < 0.00001), as did tumors on the trunk and extremities compared with head and neck cases (31% vs. 21%, respectively, p < 0.01).
Conclusions: In our series, 24% of NMSCs transected on the initial biopsy showed no residual tumor in the excision specimens, implying that some event in the interval between biopsy and excision may lead to the eradication of residual tumor. The exact mechanism is unclear, but wound healing likely plays an important role.