Changing demographics and pathology of nonmelanoma skin cancer in the last 30 years.

Background: Nonmelanoma skin cancer is a common and important public health concern. Few long-term demographic studies to evaluate potential changes in the clinical or pathologic attributes of theses lesions have been initiated.
Design: A computer-based archival search of nonmelanoma skin cancer (NMSC) diagnosed in 1972 and 2001 at a large VA medical center was examined with accompanying glass slides. The NMSC consisted of basal cell carcinoma (BCC), invasive squamous cell carcinoma (SCC) and squamous cell carcinoma in situ (SIS). Pathologic attributes examined included the histologic type of BCC (nodular, superficial, infiltrating), and histologic grade of SCC. Demographic features included age, and location. As the majority of patients were men, women were excluded from the study. The results were tabulated and statistically evaluated by the Students' t-test.
Results: A total of 831 cases of NMSC diagnosed in 809 patients in 1972 compared to 1,712 cases in 1,011 patients in 2001. BCC accounted for 45%, SIS 23%, and SCC 32% in 1972 compared to 34% BCC (P = .04), 38% SIS (P = .01), and 28% SCC (P > .05) in 2001. Histologic subtypes of BCC included nodular accounted for 45%, superficial 37% and infiltrating 7% in 1972 compared to 35% (P = .05), 46% (P > .05) and 19% (P = .01) in 2001. Among SCC, 79% were well differentiated with 13% moderate and 7% poorly differentiated in 1972 compared with 82% (P > .05), 10% (P >.05), and 8% (P > .05)in 2001. The average age of patients in 1972 was 76.2 and 64.1 in 2001 (P = .02). The most common locations in 1972 are head and neck (H&N) (54%), extremities (24%); 2001 H&N (50%) and extremities (32%, P = .05).
Conclusions: The data would suggest that NMSC is being diagnosed at a younger age and more commonly on the extremities in Veteran's than in the past. The relative proportion of SIS and of superficial and infiltrating BCC is also increasing.