Frequency of facial basal cell carcinoma does not correlate with site-specific UV exposure.

BACKGROUND

Basal cell carcinoma (BCC) is the most common type of skin cancer in whites. Long-term exposure to UV radiation is considered a major risk factor. We decided to investigate whether maximally exposed areas of the body are also the most frequent sites where BCCs develop.

DESIGN

Retrospective analysis of distribution and histopathologic features of 3065 facial BCCs.

SETTING

University hospital.

PATIENTS

Patients with primary or recurrent BCC of the face.

INTERVENTION

Exact topographic documentation followed by removal of BCC with Mohs prcedure and analysis of tumor extension.

MAIN OUTCOME MEASURE

To test the hypothesis that site-specific UV exposure correlates with site-specific BCC frequency.

RESULTS

The most frequent sites of BCC were the nose (n = 1373), orbital area (n = 386), and ears (n = 269). Subdivision of these anatomical units showed that most nasal BCCs are located at the base of the nose (n = 851), while the apex (n = 292) and the dorsum of the nose (n = 230) were less frequent sites despite their prominent sun exposure. The shaded retroauricular fold (n = 99) and the sun-exposed preauricular crest (n = 105) were similar in frequency of BCCs; fewer BCCs were located on the helix of the ears (n = 65). Finally, almost 10 times more BCCs were found in the medial quadrant of the orbit (n = 225) than in the lateral quadrant (n=24). No correlation between prominent UV-exposed facial contours and particular histologic features, such as solid, morpheaform, or adenoid-cystic, could be established.

CONCLUSIONS

Site-specific cumulative UV exposure alone is a poor predictor of frequency or histologic features of BCC. Additional site-specific textural qualities of facial skin may be considered as potential cofactors for the development of BCC.