The epidemiology of basal cell carcinoma

摘要: Basal cell carcinoma (BCC) is a skin cancer of particular importance to the Australian community. Its rate occurrence highest in Queensland, where 1% 2% people are newly affected annually. This an order magnitude higher than corresponding incidence estimates European and North American populations. Individuals with sun-sensitive complexion particularly susceptible because sun exposure single most important causative agent, as shown by anatomic distribution BCC which general consistent levels across body sites. A distinguishing feature multiple primary tumours within individuals, synchronously or over time, their diagnosis treatment costs contribute substantially major public health burden caused BCC. knowledge gap about pathogenesis however was understanding true frequency occurrences distribution, why proportion do develop more one life. This research project sought address this under overarching aim better understand detailed epidemiology ultimate goal reducing through prevention. The document prospectively its associations constitutional environmental (solar) factors, all while paying special attention persons study built on previous findings recent developments field but set out confirm extend these propose adequate theories complex cancer. Addressing goals required new approach researching basal carcinoma, due need account for phenomenon incident BCCs per person. enabled 20 year community-based Australians that provided methodological foundation thesis. Study participants were originally randomly selected 1986 from electoral register adult residents subtropical township Nambour Australia. On various occasions during study, fully examined dermatologists who documented cumulative photodamage well cancers. Participants completed standard questionnaires cancer-related consented have any diagnosed cancers notified investigators regional pathology laboratories Queensland. These methods allowed 100% ascertainment histologically confirmed population. 1339 had complete follow-up end 2007. Statistical analyses thesis carried using SAS SUDAAN statistical software packages. Modelling methods, including multivariate logistic regressions, repeated measures terms innovative gave two levels, presented five chapters scientific papers: 1. Incidence multiplicity distribution: longitudinal population times 705 100,000 person years compared singly 935 years. Among multiply alike, site-specific rates far facial subsites, followed upper limbs, trunk, then lower limbs 2. Melanocytic nevi carcinoma: there association? BCC risk significantly increased those forearm (Odds Ratios (OR) 1.43, 95% Confidence Intervals (CI) 1.09-1.89) without nevi, especially among spent time mainly outdoors (OR 1.6, 95%CI 1.1-2.3) indoors. Nevi back not associated BCC. 3. Clinical signs site: 16-year Over period, 58% developed 60% different high numbers solar keratoses, likely experience counts overall 3.3, 1.4-13.5). Occurrences trunk 1.4-7.6) 3.7, 2.0-7.0) strongly keratoses sites. 4. Occurrence determinants histological subtype community 1202 BCCs, 77% growth pattern 23% mixed composition. nodular superficial patterns commonest. Risk head raised if 5 present face 1.8, 1.2-2.7 OR 4.5, 2.1-9.7 respectively) similarly presence 4.2, 1.5-11.9 2.2, 1.1-4.4 respectively). 5. exposure: Dermal elastosis be seen adjacent neck (p=0.01). Severity dermal each site increasing clinical cutaneous damage site. occurred perilesional se, always found region photodamage. This thus has identified BCCs. It does support view represent distinct group prone certain results also demonstrate regardless site, histology causing skin, hence challenge occurring sites typically low opportunities association sun-exposed sites, respectively. Through dissemination medical literature, at large, can ultimately assist secondary prevention BCC, perhaps high-risk