Reinforcement learning AI model improves accuracy of skin cancer diagnoses

2nd August 2023

Using a reinforcement learning model that includes human preferences, improves the diagnostic accuracy of artificial intelligence (AI) decision support systems for skin cancer, according to the findings of a recent study.

Published in the journal Nature Medicine, researchers from the Department of Dermatology at MedUni Vienna in Austria integrated human decision-making criteria in the form of ‘reward tables‘ into the AI diagnostic system.

This reinforcement learning – a subset of machine learning – allows the system to learn through trial and error, based on both positive and negative feedback from its actions. In other words, it learns from its mistakes and is designed to mimic natural intelligence as closely as possible.

The dermatologist-generated reward tables incorporated the positive and negative consequences of clinical assessments into the decision-making process, from both the physician‘s and the patient‘s perspective. Consequently, an AI diagnosis was not only rated as right or wrong, but rewarded or penalised with a certain number of plus or minus points depending on the impact of the diagnosis or the resulting decisions.

The researchers found greater accuracy in AI diagnostic results was achieved by incorporating this human decision-making criteria, which was designed to balance the benefits and harms of various diagnostic errors, using melanoma and other skin cancers as an example.

Reinforcement learning and diagnostic accuracy

When compared against supervised learning, the reinforcement learning model improved the sensitivity for melanoma diagnosis from 61.4% to 79.5% and for basal cell carcinoma from 79.4% to 87.1%. AI overconfidence was also reduced while simultaneously maintaining accuracy.

In addition, reinforcement learning increased the rate of correct diagnoses made by dermatologists by 12.0% and improved the rate of optimal management decisions from 57.4% to 65.3%.

Commenting on the importance of the results, study lead Harald Kittler, said: ‘In this way, the AI learned to take into account not only image-based features, but also consequences of misdiagnosis in the assessment of benign and malignant skin manifestations.‘

The improved performance of AI-based skin cancer diagnosis also occurs because reinforcement learning reduces the AI‘s overconfidence in its own predictions, making more nuanced and human-compatible suggestions.

‘This, in turn, helps physicians make more accurate decisions tailored to individual patients in complex medical scenarios,‘ Kittler added.

Faster diagnosis and treatment for skin cancer as NHS plans accelerated rollout of teledermatology

9th June 2023

Skin cancer diagnosis will be achieved faster and closer to homes as the NHS is set to accelerate the rollout of teledermatology across specialist services and GP practices.

The diagnostic technology, which involves taking high resolution images of spots, moles or lesions on people’s skin, uses a small lens the size of a 50p piece attached to a phone camera. Known as a dermatoscope, it enables specialist dermatologists to double the number of patients they can review in a day.

Currently used in about 15% of trusts offering dermatology services, teledermatology is set to be rolled out to all areas of the country by July this year.

The use of dermatoscopes is also being expanded across GP practices and community diagnostic centres, which can support people living in rural communities to get a faster diagnosis without having to travel for a specialist appointment or avoid the requirement to attend a specialist.

This means people will be able to start treatment more quickly, helping to reduce waiting times and improving chances of survival.

Some hospitals are seeing almost all patient’s diagnosed and treated for skin cancer within two months of an urgent GP referral thanks to teledermatology, according to the NHS.

Skin cancer checks on the rise

According to the NHS, more than 600,000 people have been referred for skin cancer checks in the last year – almost a tenth (9%) higher than in the previous year and double the number sent for checks almost a decade ago. Over 56,000 patients with skin cancer received treatment last year.

According to Cancer Research UK, There could be around 26,500 new cases of melanoma skin cancer every year in the UK by 2038-2040, projections suggest.

Announcing the rollout, NHS chief executive Amanda Pritchard said: ‘There is no denying that increased demand has placed huge pressure on services, but championing the use of digital technology and new ways of working is key to reducing waits and is exactly why we are accelerating the use of teledermatology – it is a small piece of kit that has the potential to speed up diagnosis and treatment for tens of thousands with skin cancer.’

Somerset GP Dr Tom While said: ‘Being able to get a swift and specialist opinion on a skin lesion or rash, and advice on treatment or local surgical options, often negates the need to refer the patient on to another hospital to see the specialist in person. This not only reduces waiting lists, but strongly benefits my patients who live in rural areas, saving them from long unnecessary journeys.

‘If a patient does need to be referred on to a specialist, then the teledermatology service helps to streamline that process, ensuring the patient is seen in the correct clinic at the right time.’

AI-supported diagnostic technology

Magnifying lenses that use artificial intelligence technology to identify the presence of cancerous skin lesions are also being trialled by the NHS.

Ms Pritchard highlighted that the technology is ‘proving highly effective in areas that have trialled the technology so far’, with 10,000 unneeded face-to-face appointments avoided so far.

The technology, known as Deep Ensemble for the Recognition of Malignancy (DERM), is initially being used alongside clinician assessments, but it is hoped it will provide both faster and more accurate skin cancer detection.

Neil Daly, founder and CEO of Skin Analytics – the company behind the DERM technology – said: ‘Our mission is to help more people survive skin cancer and by providing easier access to skin cancer assessments and we are excited to help additional hospitals see more patients faster through the use of our DERM technology.

‘The NHS’s decision to roll out DERM to support teledermatology is another positive example of the NHS championing world-leading technologies and the next generation of dermatology pathways.’

Sun awareness measures failing to alter behaviour

14th September 2022

Sun awareness measures are not followed by large numbers of European and non-Europeans increasing their risk of developing skin cancer

Sun awareness messages do not appear to be registering with patients and could potentially increase their risk of developing skin cancer according to the findings of a survey by La Roche-Posay and IPSOS and discussed at the 31st EADV Congress.

The latest data suggests that 1.71% of the adult European general population reported having skin cancer, meaning some 7,304,000 individuals are estimated to have the disease.

Now in data from a survey of 17,000 people from 17 countries, including 6,000 people from the UK, Germany, France, Spain, Italy, and Russia and from North and South America, Africa, Oceania, and Asia, researchers have highlighted that sun awareness messaging does not appear to be acted upon by a large number of people.

The results clearly demonstrated that there is a perpetuation of several ‘myths’. For example, 73% of European said that a tan was healthy although among non-Europeans, this figure dropped to 59%. The majority of Europeans (80%) also believed that tans are attractive though again, this perception was less common (67%) among non-Europeans.

Perhaps of greater concern was how although 92% of Europeans were aware of the skin ageing risks posed by the sun, 84% admitted that they did not protect themselves all year round.

Other misconceptions which highlighted either a poor understanding or deliberately ignoring sun awareness messaging, include how only 56% of Europeans knew that sun protection was useful when the weather was overcast. In fact, nearly a quarter (24%) thought it was safe to go outside without sun protection when they were already tanned.

Additionally, only 1 in 10 (10%) of Europeans said they routinely or often used all forms of sun protection, such as applying sunscreen, staying in the shade, wearing a hat and protective clothing all year round, compared to 14% of those from outside of Europe.

Another worrisome finding was that while sun awareness of the dangers of the sun were higher in at-risk groups (i.e., those with a history of skin cancer, pre-cancerous lesions, photo dermatosis, or those taking photosensitising or immunosuppressing drugs), 59% still reported that they could not imagine coming back from a holiday without a tan.

Commenting on these findings, lead researcher Professor Thierry Passeron said: ‘This research shows just how entrenched the “healthy” suntan myth is – even in those who have already suffered sun damage or developed skin cancer.’

He added: ‘We must drive awareness of the damage to skin cells caused by exposure to the sun, which can lead to photoaging and skin cancer. This is particularly important in Europe where sun protection appears most inadequate compared to other countries.’

Citation
Sun Exposure and Associated Risks in 17 Countries: Results from Europe Compared to Other Continents.

thought it was safe to go outside without sun protection when they were already tanned (vs 21% outside of Europe)

Basal cell carcinoma diagnosis improved with novel imaging technique

9th September 2022

The diagnosis of basal cell carcinoma has been improved over both clinical and dermoscopic examination with a novel imaging technique

Basal cell carcinoma can be diagnosed more accurately than with either clinical or dermoscopic examination using a novel imaging technique according to data presented at the 31st European Academy of Dermatology and Venereology (EADV) Congress by researchers from the Department of Dermatology at the Hôpital Erasme, Université Libre de Bruxelles, Brussels.

Basal cell carcinoma (BCC) is the most frequently diagnosed malignancy worldwide and a Dutch study found that over the period 2001-2019, the age-standardised incidence rates for both men and women with a first BCC increased from 157 to 304 and from 124 to 274 per 100 000 person-years, respectively.

Furthermore, the authors of the study concluded that ‘the incidence continues to rise in patients aged 50 years and older. In the next decade a further increase in BCC incidence is expected.’

According to the European Skin Cancer Foundation, in Europe the incidence is of BCC is about 50 to 80 new patients per 100.00 persons per year but which is less than in Australia, where the incidence is about 250 per 100.00 persons per year and with upward trend.

In the current study, researchers found that using a new, non-invasive skin imaging technology called line-field confocal optical coherence tomography (LC-OCT), which gives detailed 3D images at cellular level, significantly increased diagnostic accuracy. 

For the differentiation of BCC from BCC-imitators (such as squamous cell carcinoma, actinic and seborrheic keratosis, dermal nevus, and inflammatory conditions), the researchers analysed 303 lesions, including 173 BCC and 130 BCC-imitators.

They found that LC-OCT significantly increased the diagnostic accuracy by 12% compared to dermoscopic examination alone (from 85% up to 97%), which the most commonly used skin cancer diagnostic technique. 

Importantly, for the differentiation of superficial BCC (a subtype that can be treated non-surgically) from other BCC subtypes, using LC-OCT again increased the diagnostic accuracy by 12% compared to dermoscopic examination alone (from 80% to 92%). 

The study also produced a diagnostic algorithm useful to guide the clinician’s diagnosis towards different BCC and BCC-imitators’ subtypes. The algorithm is based on the most powerful LC-OCT morphological criteria that came out from their comprehensive statistical analysis. 

Professor Mariano Suppa, a lead researcher and consultant dermatologist from Italy said: ‘Our findings suggest that, when in front of an BCC equivocal lesion, LC-OCT enables a more accurate diagnosis and, therefore, should be included in the diagnostic process and management of BCC.’

Prof. Suppa added: ‘LC-OCT has the potential to reduce the number of unnecessary biopsies and excisions in cases of superficial BCC and also in the case of benign lesions that do not require surgery.’

Topical calcineurin inhibitor use associated with minimal increased risk of cancers

9th April 2021

In 2006, authorities noted a potential risk of skin cancer from using topical calcineurin inhibitors but over the years the evidence suggests that these risks are very small.

There are currently two topical calcineurin inhibitors (TCI) available and indicated for the second-line management of atopic eczema: pimecrolimus and tacrolimus. Both drugs have an immunosuppressant effect and there is a potential risk of malignancy when administered systemically. Nevertheless, whether this same level of risk applies to topical use is unclear but in 2006 the European Medicines Agency described an increased risk of cancer associated with topical use based on the findings from animal studies. In trying to determine if studies since 2006 have reported an increased incidence of cancer from topical use, a team from the Michael G DeGroote School of Medicine, McMaster University, Ontario, Canada, conducted a systematic review and meta-analysis to examine this association. A literature search was undertaken in all of the major medical databases (e.g., MEDLINE, EmBase etc) from inception to August 2020. Included studies were those investigating the association between treatment with TCIs and the incidence of cancer or cancer mortality but not limited to treatment of atopic eczema. In addition, the team performed a subgroup analysis separating both TCIs and for studies limited to children.

Findings
In total, 8 cohort studies including 408,366 treated participants with a mean age of 17.1 years (55.1% female) were included in the analysis. In all but one of the studies, TCIs were used to treat patients with atopic eczema with the remaining study including seborrheic dermatitis, atopic eczema, contact dermatitis and sunburn. There was no association between the use of TCI and overall cancer (relative risk, RR = 1.03, 95% CI 0.92–1.16). However, in 5 of the studies there was an increased risk of lymphoma (RR = 1.86, 95% CI 1.39–2.49) and this risk was elevated for both TCIs. In addition, in studies where the comparator was topical corticosteroids, the pooled risk of lymphoma was also increased (RR = 1.35, 95% CI 1.13–1.61) but there was no association found between TCI use and either melanoma or keratinocyte carcinoma.

Discussing their findings, the authors noted how although the data suggested a 35% increased risk of lymphoma from TCI use, lymphomas are extremely rare with an incidence rate of 1.35 per 100,000 in children and 9.88 per 100,000 in adults. They calculated that the number needed to harm from TCI use in children would be in excess of 200,000 and almost 30,000 in adults.

The authors concluded that while their study did suggest an increased risk of lymphoma, the absolute risk was very small for any given patient.

Citation
Lam M et al. Association Between Topical Calcineurin Inhibitor use and risk of cancer, including lymphoma, keratinocyte carcinoma, and melanoma: A Systematic Review and Meta-analysis. JAMA Dermatol 2021.