12 June 2015
WCD 2015 Vancouver - Debate on the melanoma epidemic, dermatoscope advice, viruses and cancer
We have reached the last day of the World Congress in Vancouver, and it is quite naturally the perfect time to sum up this 23rd edition: 11,561 delegates on site, 271 sessions, 4,562 individual presentations, etc. It was a pleasure for us to take part in this major event in the beautiful town of Vancouver, and we were pleased so many of you could join us remotely. We hope we met all your expectations, and made you want to go to Milan for the 24th World Congress in 2019! For the last time, please welcome our 3 on-site dermatologists, who we would like to thank for their hard work.
Is the melanoma epidemic real or is it an aggressive diagnosis artefact?
For: Dr Jason Rivers (Vancouver) , Dr Darrell Riger (New-York)
Against: Dr Earl Glusac (USA)
By Dr Florence Corgibet
For: Dr Jason RIVERS (Vancouver ), Dr Darrell Riger (New-York)
It is real because:
1. Unlike all other cancers, melanoma's incidence increases across the world, even in countries that do not have screening campaigns.
2. The absolute number of thick melanomas is steadily increasing, thus leading to a constant rise in mortality, also partly caused by thin melanomas as these can metastasize.
3. The increase in melanomas cannot be explained statistically by the growing age of the world population.
4. An epidemic is the only feasible explanation why the survival rate for melanoma patients has risen, despite the steady increase in mortality (in France too, shifting from 1.3 to 2.8/100K: Le Blanc Ann Dermatol Venerol 2013).
5. The increase in melanoma is probably underestimated (perhaps within a range of 30 to 40% in various American studies, and 20 to 25% in Belgium!) as there are no actual melanoma registers, and many patients are treated outside hospitals.
His conclusion: "it looks like a duck, it smells like a duck, it quacks like a duck, meaning it is a duck until proof of the contrary is shown"
Against: Dr Earl GLUSAC ( USA)
It is overestimated because:
1. Screening campaigns have caused the artificial rise in melanoma incidence.
2. The fear of missing a case of melanoma leads to more resections, and more biopsies-resections lead to the diagnosis of more melanomas.
3. Histological criteria that are not strict enough for melanoma lead to more frequent diagnoses by histologists, especially those that are not specialised.
4. Statistical techniques have improves and counting is made easier.
5. The increase in melanoma incidence is mostly caused by thin melanomas that may have not resulted in illness.
6. The general public is probably excessively worried, meaning that screening is increasing.
The speaker drew a comparison with prostate cancer.
Melanoma presents a statistical flaw: cells that have the same histological features as cancer cells, but that probably do not have the same progression capabilities, just like for prostate cancer (the excessive diagnosis of which has recently been noticed), as opposed to colon or cervical cancer in which dysplasia automatically leads to cancer. These two types of cancer reached a detection peak when screening techniques were improved, and their incidence is now lower, which proves the screening worked. This is not the case for melanoma.
Let's carry on using our beloved dermatoscope +++ By Dr Florence Corgibet
A few dermoscopic gems to finish off:
- The polarised light dermatoscope is preferred for the scalp as it provides an improved vision of the intertwined vessels in psoriasis, and large/telangiectatic vessels in seborrhoeic dermatitis.
- Scalp pruritus is extremely frequent in dermatomyositis, as is a red scalp either with or without diffuse alopecia. Dermoscopy is used to see the same polymorphous vessels as those seen in capillaroscopy in the proximal fold. +++
- Seeing tufts of more than 6 hairs stuck together in dermoscopy helps orientate the diagnosis towards complete folliculitis decalvans. If there are fewer than 6, the diagnosis will most likely be lichen pilaris.
- A yellow spot at the base of the nail proves the exostosis.
- Always look at the edge of the nail, not only the surface: the onychopapilloma at the end of a longitudinal melanonychia, or a Bowen at the end of a longitudinal erythroplasia, the brown holes at the end of an onychomatricoma, etc.
Viruses and cancer – Patrick Moore (Pittsburgh) By Dr Jean-François Sei
Dr Patrick Moore from the University of Pittsburgh Cancer Institute reminded us in his keynote speech that 20% of human cancers are caused by viruses - i.e. 1 of 5 cancers is virus-induced: the Epstein Barr virus was discovered in 1964, carcinogenic HPVs were discovered in 1983, Kaposi's HHV 8 herpesvirus in 1994 and the Merkel cell polyomavirus in 2006. The last two were discovered in his laboratory. The genetic revolution has made the discovery of 11 new polyomaviruses possible over the last 8 years, and over 200 papillomaviruses have been described to date, some of which are carcinogenic. The virus-induced carcinogenic process includes a number of stages: infection often occurs early and possibly even as a child (this is the case for polyomaviruses), then comes the latence stage, the integration of the viral genome in certain cells then - thanks to co-factors (reduced immune surveillance due to immunosuppression, old age, UV rays or certain toxic agents) - the malignant proliferation begins. The onset of cutaneous Squamous Cell Carcinoma in transplanted patients highlights the role of HPVs. Moreover, Bertrand Richert stated in a recent publication that nail Squamous Cell Carcinoma is most often linked to HPV 16 - thus opening up prevention possibilities for certain cancers through vaccines.