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[8 min read] Detecting melanoma in high-risk patients | Prof David Wilkinson
This month I draw your attention to what I believe is a profoundly important piece of research. The research – done in Australia – demonstrates the value of using a mixture of total body photography (TBP) and selected sequential digital dermoscopy (SDDI) among high risk patients, in terms of identifying melanoma.
The authors state the following in the Abstract Results:
The risk of developing a new melanoma was 9.0% annually in the first 2 years and increased with time, particularly for those with multiple primary melanomas. The thicker melanomas (>1-mm Breslow thickness; 7 of 171 melanomas [4.1%]) were mostly desmoplastic or nodular (4 of 7), self-detected (2 of 7), or clinician detected without the aid of TBP (3 of 7).
Overall, new melanomas were most likely to be detected by a clinician with the aid of TBP (54 of 171 [31.6%]) followed by digital dermoscopy monitoring (50 of 171 [29.2%]).
Importantly, this work included a primary care clinic in Newcastle, NSW.
The implications are significant – implying that standard of care now for patients at high risk of melanoma includes TBP and SDDI.
The paper is linked here and there is very interesting podcast with the lead author available here, showcasing the research.
Prof David Wilkinson
6 comments on “[8 min read] Detecting melanoma in high-risk patients | Prof David Wilkinson”
Thanks for posting this paper and the podcast link.
I think there is still more work to be done before TBP and SDDI can be considered standard of care in high-risk patients.
In this paper, melanoma detection has been coded as “with the aid of TBP” when the clinician detected the melanoma on clinical examination as well as with TBP which was referred to AFTER the clinical examination in which the lesion had already been detected. This doesn’t mean that lesion would have been missed if the clinician wasn’t using TBP. Therefore the conclusion in the abstract of 31.6% of lesions detected by a clinician “with the aid of TBP” is very misleading. This doesn’t mean those lesions were not detected without TBP. Similarly, the study doesn’t say if change on SDDI was the only reason the lesion was excised and therefore it may have been excised regardless of comparison to earlier photos. Only 11 of the 171 melanomas were detected “exclusively by TBP” and none of the 7 melanomas over 1mm thick were detected exclusively by TBP. This means it is likely that all the thick melanomas and 160 melanomas in total would have been detected without TBP or SDDI.
Also, the ratio of MIS : invasive melanoma is too low in this study when compared to other published rates. This study has a rate of 2.2:1 which is lower than published rates of around 3-4:1. SCARD pooled data is 3.01:1. This may mean that MIS is being missed or monitored by this approach of SDDI. Therefore, the total number of melanomas detected in this study may well have been higher WITHOUT SDDI as some of these lesions would have been excised and diagnosed as early melanomas.
A loss to follow up of 14.4% in this study also highlights the risk of SDDI in patients as they often don’t come back and sometimes immediate biopsy is a safer approach.
Also, the “high-risk” population in this study is extremely high-risk. They are not just patients with a history of melanoma. The inclusion criteria was
a history of melanoma PLUS DNS (>100 naevi including at least 6 atypical)
a history of melanoma PLUS 3 first-degree or second-degree relatives with MM
two previous melanoma with one occurring within the last 10y
a CDKN2A mutation
These are very “high risk” patients. Extrapolating any data from this group to the general population is difficult.
I think the use of TBP/SDDI needs to be compared against standard care before it’s use can be advocated by HealthCert. We still don’t know if there are improved patient outcomes using it. TBP/SDDI is expensive for patients and for practices to set up and can be time consuming. The risk of loss to follow up using SDDI is high. It will be interesting to see the outcomes of a randomised control trial in this field.
Hilary – some really useful comments here. Thanks for contributing to the discussion and debate on what is a critically important issue. You may know whether an appropriate RCT is underway – I don’t. I wonder what the trial would be? Presumably TBP plus SDDI vs standard clinical care? Seeking to answer the question “if we add TBP plus SDDI to usual care will we detect more melanoma / reduce melanoma-specific mortality / reduce all-cause mortality. Tricky to do, long time to do, not sure of ethical approval (among high / very high risk patients).
Worth noting that TBP/SDDI (in some form of protocol) is indeed already the standard of care in specialist (non-primary care). That is, this is what centres of excellence, especially in academic medical settings have been doing for some time now.
What interests me, and what I think is most relevant to us is, what this means for primary care. There is no established standard for primary care – literally. We have an opportunity to develop one (through research and development). It seems to me now that we are beholden now to do a couple of things. One is to formally assess each patient’s risk of melanoma / skin cancer, and then second is to direct patients into a risk-stratified pathway of care that is designed to meet their needs.
I find myself reflecting on personal circumstances. I am at “high risk” of melanoma through a family history. Up until recently I was content to do regular self-examination and GP skin check. Now, I am not content with that – imaging will, I know increase the likelihood of any melanoma being detected earlier. (This is a fact – how much more likely etc is not known, certainly). And, while I know that many melanomas grow slowly, and that (surely) some disappear, and that many lesions are over-called by pathologists, I really do not want an early “melanoma” left on me………and I wouldn’t want that for my patients.
So, I think we are left with the challenging of working out how this technology is used rationally in primary care….
Add to that : how are we going to cope with rural patients too far from tertiary centres , and rural centres with no cameras but mobile phones : )
Excision often best option
Lions Club are now running a mobile unit in regional areas for those country folk that cannot make it to the city skin check clinics. It will be maned by volunteers that have passed the health Cert dermoscopy certificate using a dermatoscope. Certainly not diagnosing but marking spots of concern on an anatomy chart for the clients to take to their gp. We are hoping to catch a lot of early skin cancers.