Special features of non-melanoma skin cancer in Hong Kong Chinese patients: 10-year retrospective study.

OBJECTIVE To determine the incidence and clinical characteristics of non-melanoma skin cancer in Hong Kong Chinese patients. DESIGN Retrospective study. SETTING Social Hygiene Services, Hong Kong. PATIENTS Records of 528 Chinese patients with a histological diagnosis of non-melanoma skin cancer from 1990 to 1999 were reviewed. MAIN OUTCOME MEASURES Demographic data, site and clinical type of cancer, predisposing factors, history, recurrence, and the development of new skin cancers. RESULTS Non-melanoma skin cancer is uncommon but not rare among the Chinese population in Hong Kong. The incidence of newly diagnosed basal cell carcinoma in 1990 was 16.0 per 10,000 new skin case attendances and, in 1999, the incidence was 31.8 per 10,000 new skin case attendances. The corresponding figures for squamous cell carcinoma in 1990 and 1999 were 6.9 and 11.6 per 10,000 new skin case attendances. The incidence of basal cell carcinoma among the Hong Kong Chinese population in 1990 and 1999 was 0.32 and 0.92 per 100,000, respectively, whereas that of squamous cell carcinoma was 0.16 and 0.34 per 100,000, respectively. Demographic data and the site distribution of non-melanoma skin cancer were comparable to those reported in Caucasians living in North America and Europe, but different from those in Caucasians living in Australia and Hawaii. Pigmented basal cell carcinoma was the most common type of non-melanoma skin cancer (60.1%) in Chinese patients, in contrast with rodent ulceration in Caucasian. Multiple skin cancers, recurrence, and subsequent new skin cancers were less frequently observed than in studies of Caucasians. CONCLUSION When compared with reported findings in Caucasians, Chinese patients show differences in the clinical type and multiplicity of lesions, predisposing factors, recurrence, and subsequent new skin cancer rates for non-melanoma skin cancer. Pigmented basal cell carcinoma seems to be an important differential diagnosis with regard to pigmented lesions in the Chinese population.