Aim: To investigate cancer cell absence or presence in wide excision after biopsy of squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) patients.
Methods: 200 patients (100 BCC and 100 SCC) from the same dermatology clinic, who had positive margin upon biopsy, were selected from a computer generated randomized report. All selected patients had wide excision following biopsy. To determine the correlation of gender, age distribution and cancer absence, BCC and SCC cases were separated based on excision-cancer absent or present after wide excision. χ(2) tests, Fisher's exact tests were used to analyze the ratio of male to female between excision-cancer absent and excision-cancer present patients, while Mann-Whitney U test were used to compare the age distribution in the two groups. Statistical analyses were performed using SPSS version 16.0 for Windows.
Results: Our retrospective chart review of the patients showed that cancer cells were absent in 49% of BCC patients (n = 100) and 64% of SCC patients (n = 100) who had previously had positive margins upon biopsy. Gender analysis showed the ratio of male to female (M/F) in the BCC arm was significantly higher compared with the SCC arm in those with excision-cancer absent (2.06 vs 0.66; P = 0.004; χ(2) test). But M/F of excision-cancer absent and excision-cancer present in neither BCC nor SCC patients was statistically significant. Age adjustment showed no significant difference between excision-cancer absent and excision-cancer present in BCC and SCC patients. Nevertheless, in excision-cancer absent cases, the age distribution showed that the BCC patients were younger than SCC patients (average age 67 vs 74; P < 0.001; Mann-Whitney U test). In addition, our data also indicated that in the patient group of 71-80 years old, there were more SCC patients who showed excision-cancer absence (67.6% vs 39.4%; P = 0.02; χ(2) test).
Conclusion: Our study indicates that approximately 50% or more of BCC and SCC patients with positive margins found on biopsies did not have cancer cells present at the time of wide excisions.
Keywords: Biopsy; Histology; Positive margin; Skin cancer; Wide excision.