Patients are rubbish at spotting their own malignancies. GPs aren’t perfect at it, either.
This Back Page correspondent started school in the early 80s – long ago, but hardly in the pre-medical era. We clearly remember our very first teacher telling us her aunt had died of melanoma and warning us on the dangers of sunbaking.
That same school forced every child out into the Australian midday sun, unhatted and unsunscreened, for recess and lunch every day (unless rain), with few shade options, to soak up that ultraviolet goodness through the generous hole in the ozone layer.
At the dermatologist’s last week for a skin check, we pondered aloud whether some sort of lawsuit would be appropriate if a malignancy were found (it was mercifully not).
The doctor said charitably that “there was less knowledge back then” (again, we’re talking 80s AD, not BC), and reminded us of the ABCDE mnemonic for spotting melanoma: asymmetry, border, colour, diameter, evolving.
Doesn’t roll off the tongue, does it?
Add to that the fact that the little buggers can pop up anywhere, not only on the back but in hard-to-reach places where the sun don’t even shine, and it’s not surprising that people are no good at recognising their own melanomas.
That’s the finding of an Australian study that set out to test the soundness of self-skin checks, which are “a key part of Australia’s National Strategy for reducing the impact and burden” of malignant melanoma.
According to the authors, it’s also advised in the RACGP red book that “patients deemed at high risk (previous history MM or greater than five atypical naevi) should be advised to conduct self-skin examinations every three months”; however, that advice may have been updated since this paper was put together, as we can’t find it.
With GPs taking on more and more skin work, previous research has compared GPs and specialist skin cancer doctors on their chops at spotting skin cancers and melanomas specifically. For skin cancers generally, they found no significant difference in sensitivity; but for distinguishing melanoma from the rest, GPs had a lousy 29% sensitivity compared with the specialists’ 60%.
Another study found GPs could correctly spot a melanoma 50% of the time immediately after training, but that this modest success rate plummeted after a year’s interval.
The authors are sceptical of the Melanoma Institute Australia’s claim that more than half of all melanomas are first identified by the patient. The source is uncited, and “[r]egardless, if approximately one half of melanomas are purported to be self-detected, this would equate to a sensitivity of approximately 0.50, which is almost double the sensitivity observed in the [Youl et al. study cited above] of GPs (0.29), who are medically trained to recognise MMs.”
In the present study, participants were people who attended a skin cancer clinic by referral or choice. They filled in a survey on physiological demographics, sun exposure relevant to an activity, techniques for preventing skin cancer, and skin cancer risk and history, and were asked if they had any concerning lesions.
Clinicians used an AI-assisted dermatoscope to give them a full-body check – the AI generated a melanoma risk score for all suspicious lesions. There were 260 patients with suspected melanoma, 83 of which were confirmed as such by histopathology.
Of these 83 patients more than two-thirds had family history of melanoma and one-third had already had a melanoma themselves, so you’d think they’d be more aware than the average.
Yet only 18 of these patients, just under 22%, “were able to recognise a lesion of concern”. This awareness did not correspond with lesion size, but patients were more likely to correctly identify an invasive melanoma as opposed to an in situ one (27.3% versus 21.3%).
Of the negative patients, 31 incorrectly identified a lesion as being of concern, for an 18% false positive rate.
The authors conclude by recommending that screening guidelines be revisited “in an effort to promote early detection, improved patient outcomes and reduce the economic burden” of melanoma, in which we are the uncontested world leader.
They stop short, disappointingly, of recommending all 40s-and-older Australians sue their primary schools for sun damage(s).
Send bronzed Aussie story tips to penny@medicalrepublic.com.au.
