Neale Rachel E, Davis Marcia, Pandeya Nirmala, Whiteman David C, Green Adele C
Viertel Centre for Research in Cancer Control, Queensland Cancer Fund, Spring Hill, Queensland, Australia.
J Am Acad Dermatol. 2007 Mar;56(3):380-6. doi: 10.1016/j.jaad.2006.08.039. Epub 2006 Oct 13.
Basal cell carcinoma (BCC) is the most common of all cancers. Ultraviolet radiation is the major etiologic agent in the pathogenesis of BCC, but there is not a straightforward relationship between cumulative exposure and risk. A high proportion of lesions arise on the trunk, which is generally much less exposed to the sun than the head, the major site affected. We tested the hypothesis that the phenotypic determinants and patterns of sun exposure that give rise to BCC on the head and trunk vary in a way that explains the anomalous site distribution.
The study was set in the context of the Nambour Skin Cancer Study, a community-based follow-up study among 1621 participants with virtually complete ascertainment of BCCs between 1992 and 2004. We compared phenotypic and sun exposure characteristics of participants who developed a first BCC of the head or trunk with those of participants who had no diagnosis of BCC.
BCCs of the trunk were more likely to occur in men; they also occurred at a younger age than BCCs of the head. There was a positive association between sun sensitivity and BCC of the head that was absent for BCC of the trunk. A high number of solar keratoses conferred a greater than 3-fold risk for BCCs of both the head and the trunk. BCCs of the trunk had a particularly strong association with the number of reported sunburns and solar lentigines on the trunk, whereas many lentigines conferred a greater than 3-fold risk of truncal BCC compared with a 50% increased risk of BCC of the head.
The relatively small numbers of tumors may have limited our ability to detect statistically significant differences.
BCCs of the trunk are the result of overexposure of the sensitive basal cells of the epidermis to ultraviolet radiation. This may result from acute intense exposures sufficient to cause sunburn among people whose ability to tan makes the skin of their face generally less susceptible to the carcinogenic effects of ultraviolet radiation.
基底细胞癌（BCC）是所有癌症中最常见的。紫外线辐射是基底细胞癌发病机制中的主要病因，但累积暴露量与风险之间并非简单的线性关系。很大一部分病损发生在躯干，而躯干通常比主要受累部位头部接受阳光照射的机会少得多。我们检验了这样一个假设，即导致头部和躯干发生基底细胞癌的表型决定因素和日晒模式存在差异，这可以解释这种异常的部位分布。
本研究是在楠伯皮肤癌研究的背景下进行的，这是一项基于社区的随访研究，对1621名参与者进行了研究，在1992年至2004年间几乎完全确定了基底细胞癌病例。我们比较了首次发生头部或躯干基底细胞癌的参与者与未诊断出基底细胞癌的参与者的表型和日晒特征。
躯干基底细胞癌更易发生于男性；其发病年龄也比头部基底细胞癌患者年轻。日晒敏感性与头部基底细胞癌呈正相关，而与躯干基底细胞癌无关。大量的日光性角化病使头部和躯干基底细胞癌的发病风险增加3倍以上。躯干基底细胞癌与躯干上报告的晒伤次数和日光性雀斑密切相关，而许多雀斑使躯干基底细胞癌的发病风险增加3倍以上，相比之下，头部基底细胞癌的发病风险仅增加50%。
肿瘤数量相对较少可能限制了我们检测统计学显著差异的能力。
躯干基底细胞癌是表皮敏感基底细胞过度暴露于紫外线辐射的结果。这可能是由于急性强烈暴露足以导致晒伤，而对于那些有晒黑能力的人来说，其面部皮肤通常对紫外线辐射的致癌作用不太敏感。
