Body site distribution and relative tumor density of different human cutaneous malignancies with emphasis on sunlight exposure: A single institution experience


Vladimír Bartoš, Milada Kullová

Background: Different skin cancer types display disparate body site distribution, particularly related to sunlight exposure pattern. We evaluated the topographic distribution and relative tumor density (RTD) in a set of human cutaneous malignant melanoma (MM), basal cell carcinoma (BCC), and squamous cell carcinoma (SCC) cases. Materials and Methods: A series of 182 patients with a total of 186 MMs, 899 patients with a total of 1184 BCCs, and 114 patients with a total of 146 SCCs were analyzed. Results: MMs occurred most commonly on the trunk (46.8%) and the upper limbs (25.3%). While the back and the trunk in particular was sites with the most frequent MM development in males (64.3% and 45.9%), the upper limbs were the most common location in females (34.1%). BCCs and SCCs occurred predominantly on the head and neck, comprising a total of 69.0% and 81.5% of the cases. The face was a region with by far the highest RTDs in BCC and SCC patients. Men had more frequently affected extrafacial sites of the head and neck compared to women in both BCC (46% vs. 31.9%) and SCC (62.5% vs. 48.3%) cases. In BCC, the second most frequent anatomic site included the back in both genders (25.1% in males, 18.2% in females), but in SCC, it represented the trunk as a whole in males (13.6%), and the lower limbs in females (14.3%). The greatest differences in RTDs between BCC and SCC were on the back (BCC: SCC ratio, 7.5:1), especially in men (BCC: SCC ratio, 9:1). Conclusion: We have confirmed striking heterogeneity for skin cancer risk by anatomic site. While MMs arise predominantly on the body parts intermittently exposed to the sunlight, BCCs and especially SCCs develop most frequently on the sites that are habitually exposed to the sun.