Melanoma is the second most common cancer in Australia overall, occurring at an age-standardised incidence of 48×10−5 person-years. Variations in melanoma incidence are evident across the country, with the populations of Queensland and Western Australia suffering the highest documented rates of melanoma in the world (65 and 53×10−5 person-years respectively). Strategies to reduce the burden of melanoma in Australia have included national primary prevention programs to reduce population exposure to sunlight (e.g. ‘Slip! Slop! Slap!’ and ‘SunSmart’ campaigns), combined with secondary prevention efforts directed towards the early detection of malignant lesions.
‘Screening’ is a term used to describe several types of early detection strategies, which may include population-wide screening, selective screening of high-risk people, and opportunistic screening (or case-finding). In Australia, population-based screening programs have been implemented for three cancers (breast, cervical and colon), but not melanoma. The Clinical Practice Guidelines for the Management of Melanoma in Australia and New Zealand states ‘in the absence of substantive evidence as to its effectiveness in reducing mortality from melanoma, population-based skin screening cannot be recommended’. Peak advisory groups have also published position statements on early detection of skin cancer and melanoma, and none has endorsed population screening for melanoma. All organisations cite the lack of clinical trial evidence on the efficacy of screening in reducing morbidity or mortality as a key reason for not advocating screening. Other cited reasons for not implementing screening include the moderate sensitivity, low specificity and low positive predictive value of visual inspection in primary care, and the consequent costs and harms incurred by excising large numbers of benign lesions. One large community-based randomised trial of melanoma screening has been piloted in Australia, but the proposed full-scale trial did not commence due to lack of funding. The trial reported that 2.4% of screened participants were found to have a histologically-confirmed skin cancer following whole-body skin examination. The positive predictive values (number of confirmed skin cancers/number of lesions excised or biopsied) for melanoma, BCC and SCC were 2.5%, 19.3% and 7.2% respectively. It is unlikely that another trial for skin cancer screening will ever be attempted in Australia.
Despite the lack of support for population screening in Australia, there has been a striking increase in opportunistic screening through skin cancer clinics. Such clinics are now commonplace in Australian cities and towns, and demand for services continues to exceed supply. The clinics are staffed by primary care doctors offering whole body skin examinations and skin cancer surgery. Concerns have been raised about the training and competence of practitioners in these settings, and there are suggestions of over-servicing such that unnecessary surgical procedures are performed for financial gain rather than patient welfare.
Early detection of skin cancer and melanoma remains a high priority for Australian practitioners, policy makers and the public. The question remains how best to achieve this.