Determination of the Frequency of Scalp Basal Cell Carcinoma Subtypes Based on Histopathology and Other Related Variables and its Comparison between Patients with and without Chronic Radio-Dermatitis

Background: Basal cell carcinoma (BCC) is the most prevalent type of skin cancer in Iran. The determination of subtype of BCC plays an essential role in the diagnosis, recurrence rate, and outcome of patients. The present study was conducted to investigate the relationship between histopathologic subtypes and demographic data, history of radiation exposure, and past medical history in the Iranian population. Method: This retrospective cross-sectional study evaluated the patients with BCC referred to Faghihi Hospital, Shiraz, Iran from 2012 to 2017. We examined all the patients with definite histologically diagnosed scalp BCC. The prevalence of different subtypes and its association with other variables were compared between the patients with and without chronic radio-dermatitis. A P-value of less than 0.05 was considered to be significant. Results: A total number of 161 patients with a cumulative number of 439 BCC lesions participated in the study. The mean age of the patients was 64.2 (± 12.38) years old. Among the patients, 113 (70.2%) were men and 48 (29.8%) were women. The total prevalence of macro-nodular, micro-nodular, and mixed aggressive was 70.2%, 49.1%, and 41.6%, respectively. Multivariate logistic regression analysis showed that excessive sun exposure increased the chance of developing micronodular and mixed aggressive lesions by 3.21 (P = 0.006) and 4.88 (P < 0.001) times, respectively. Conclusion: BCC was more aggressive in chronic radio-dermatitis patients than that in non-radio-dermatitis patients. Moreover, it was significantly different regarding age, gender, appearance, and job distribution compared with non-radio-dermatitis patients. Thus, we could suggest that BCC in chronic radio-dermatitis should be regarded as a high-risk disease, unless proven otherwise.