Prevalence of skin screening by general practitioners in regional Queensland

Queensland residents have the highest risk of melanoma in the world, carrying a lifetime estimated risk of 1 in 16 for men and 1 in 24 for women.1 While incidence has increased in recent years, melanoma mortality has remained relatively stable,2 due at least in part to public health campaigns encouraging increased awareness and early diagnosis.3

Diagnosis of melanoma depends on the clinical identification of a suspicious lesion. Population screening for melanoma by periodic whole-body skin examination can potentially lead to earlier diagnosis, thinner tumours and fewer deaths, but there is no randomised-trial evidence to support this.4-6 Nevertheless, screening of the skin for early signs of cancer is a common clinical procedure.

It was the aim of our study to establish the current prevalence and predictors of skin examination by general practitioners in regional Queensland, in preparation for a randomised controlled trial (RCT) of a community-based screening program for melanoma.7

Melanoma risk factors. The prevalence of melanoma risk factors among participants is summarised in Box 1 and Box 2: 25% of participants reported that they always burn without tanning after 30 minutes of unprotected sun exposure, 53% reported the removal of a mole or spot in the past, 3% reported a personal history of melanoma and 9% reported a personal history of non-melanoma skin cancer. A quarter of participants reported a family history of melanoma, and a similar number reported a family history of other skin cancer. In the additional, more detailed survey of melanoma risk factors (n = 727), 21% of participants reported having some or many moles.

Concern about skin cancer and perceived likelihood of developing skin cancer. Almost a quarter (22%) of participants reported they were concerned about a specific growth or mole at the time of the survey, 39% were very concerned about skin cancer, and almost a third (32%) thought it very likely that they would develop skin cancer in the future (Box 3).

Attitude towards skin screening. Attitudes towards skin screening were consistently positive (Box 3). Seventy-nine percent of participants had confidence in their GP’s ability to diagnose skin cancer, and only 8% said that skin checks would be embarrassing.

Prevalence of skin screening. Eleven per cent (95% CI, 8.7%–13.9%) of participants reported that they had had a whole-body skin examination by their GP during the previous 12 months, and 20% (95% CI, 16.2%–23.4%) during the previous 3 years; 31% of all participants had received a part-body skin examination by their GP in the past 12 months. In total, 42% had received some form of skin examination (whole- or part-body) in the previous 12 months. There was no significant difference between men and women, or between younger (30–49 years) and older (≥ 50 years) participants in the prevalence of whole-body skin examinations (Box 4). Participants 50 years or older reported a part-body skin examination by a GP more frequently than did younger people (37.6% [95% CI, 33.6%–41.6%] versus 24.9% [95% CI, 21.9%–27.9%]; P = 0.001). The difference in part-body skin examinations between older and younger participants was observed mainly in men (38.6% [95% CI, 31.5%–45.7%] in men ≥ 50 years versus 16.4% [95% CI, 11.9%–20.8%] in men 30–49 years; P = 0.01). For women, there was no significant difference in prevalence between the two age groups.

Predictors of having had a whole-body skin examination within the previous 3 years. After simultaneous adjustment for all other factors in the multivariate regression model, factors positively associated with having a whole-body skin examination during the previous 3 years were high propensity to develop sunburn, a past history of non-melanoma skin cancer, having more than four moles on the right upper arm, having a positive attitude towards skin screening, and having confidence in the GP’s ability to diagnose skin cancer (Box 5). The odds ratios remained essentially unchanged when the analysis was applied to the 727 participants with complete data for moles on the right upper arm, and when age and sex were added to the model (data not shown).

Management of suspicious lesions. Among all survey participants, 657 (20.8%) reported that their GP had detected a suspicious freckle, spot or mole in the previous 12 months. This occurred relatively more frequently among people in the older age group than the younger age group (26.3% [95% CI, 21.8%–30.8%] versus 16.0% [95% CI, 12.9%–19.1%]; P < 0.001). Of the skin lesions detected, 420 were treated immediately, 133 were treated at a later date, 40 were still under surveillance at the time of the survey, 17 were handled by referral to another doctor for treatment, and 28 were still awaiting treatment (for the remaining 19 lesions, participants did not recall how the lesion was treated). Of the lesions treated immediately, 277 were removed through liquid nitrogen or similar substances and 142 were excised (there was one other treated lesion, for which the respondent could not recall the method of treatment). Of the 133 lesions treated at a later date, 30 were treated with liquid nitrogen and 103 were excised. All 40 lesions initially assigned for surveillance were later excised.

Our study is the first large-scale population-based survey of the prevalence of skin screening by GPs in regional Queensland, an area of high melanoma risk. Ours is one of the few Australian surveys to assess the prevalence of whole-body skin examination on a population basis — most previous surveys have not asked specifically about whole-body skin examination and thus their results are not directly comparable to ours.14-18

If skin screening programs are to improve early diagnosis of melanoma, they need to capture those at greatest risk of melanoma — ie, older people (particularly men), people with many moles, with fair pigmentation, who sunburn easily and are unable to tan, and those with a personal or family history of skin cancer.19 Our results provide some indication that people with recognised melanoma risk (ie, many moles, a tendency to burn and a personal history of non-melanoma skin cancer) were more likely to have had a whole-body skin examination by a GP in the previous 3 years. However, a limitation of our analysis is that it was based on self-report, and some results suggest that participants overstated their personal risk of skin cancer and found it difficult to differentiate between a family history of melanoma and a family history of other skin cancers (a problem reported previously in the Queensland population20). Our results may also overestimate the current prevalence of skin screening if those participating were more health-conscious and interested in skin screening than those who refused participation.

A survey of GPs’ skin-screening practices21 found that doctors strongly supported cancer screening by clinical skin examination and were more likely to include a skin examination as part of a dedicated health check-up for men than for women. However, we did not observe a difference in the number of whole-body skin examinations between men and women.

Part-body examinations were more frequent in the ≥ 50 years age group. Not surprisingly, people aged 50 years or more were treated by a GP for skin lesions more frequently than younger people.

Overall, the high prevalence of skin screening reported in our survey is likely to reflect the high awareness of skin cancer among the public in Queensland,22 which is consistent with the high level of concern about skin cancer and with positive attitudes towards skin screening expressed by most of our participants. Another Australian study revealed that most skin excisions for benign pigmented moles are performed to relieve the concerns of worried patients.23

The question of whether skin screening does in fact reduce melanoma mortality remains largely untested.