[MUSIC] Welcome to second part of this lecture on screening for cutaneous melanoma. In the first part, we've discuss how we don't have direct evidence that screening reduces melanoma mortality. Several observational studies have shown that mortality has started to decrease first in younger people and in women. This is mainly observed in countries most active in melanoma prevention. As I mentioned in the first video, melanoma control activities often combine primary prevention and early detection, such as screening convenience. It is difficult to quantify the relative contribution of screening and primary prevention, duration, favorable changes in multi-trend. Effective treatments for advanced melanoma have only very recently been available. So therapeutic improvements would not be the cause for the decline in melanoma mortality observed in several countries. Proxy of mortality could be used to evaluate screening effectiveness. Thickness is the main prosaic factor for melanoma, and survival decreases rapidly with increasing melanoma thickness and diagnosis. We can therefore, reasonably expect to see a decrease in incidence of thick melanoma as the first effect of screening before observing an impact on mortality. Today no decrease in the instance of melanoma thicker than four millimeter has been observed in any country. In some countries, the instance of thick melanomas continues to rise despite prevention efforts. In other countries, it has plateaued. Even in Australia and the US, where a decrease of melanoma incidents was recently observed for young adults. This decrease was obvious only for melanoma thinner than 1 millimeter. In the German program, stage information is not systematically collected. So no evaluation of melanoma incident by thickness is possible. So how can this absence of decrease in incidence of thick melanomas worldwide be explained? There are two main interpretations. Some believe that the stable or increasing rate of thick melanomas across different populations along with a slow rise in instance of thin melanoma, and no substantial reduction in mortality indicates that melanoma screening is rather ineffective. Others think that without screening, the same sharp increase in thick melanoma would have occurred as has been observed for thin melanoma. In other words, they believe that screening has succeeded, eliminating the true melanoma epidemic. The modest change in mortality is from a slight change as yet in incidence of thick melanoma. Given the evidence currently available, best explanation are plausible. In particular, when considering the morphologic subtype of melanoma. There's good evidence, that total body skin examination by physicians in the few years before diagnosis, reduces by about 15% the risk of being diagnosed with a thick melanoma. Screening, in particular screening by a dermatologist, causes sometimes lead to detection of melanoma that are thinner and those found during usual care. But we've not yet demonstrated that this gain in early detection translates into a drop in mortality. Indeed beyond screening, current evidence about the lethal consequences of the delayed diagnosis of melanoma is not very consistent. What are the harms of screening for melanoma and what evidence do we have? As for any screening test, visual skin inspection leads to false-positive and false-negative results. False-positive results generate unnecessary biopsies and possibly cosmetic adverse effects, costs, and anxiety. False-negative results can create false reassurance of patients. We have some evidence that screening accuracy is higher in terms of sensitivity and specificity, hence leads to fewer misdiagnosis when skin examination is performed by dermatologist rather than a primary care physician. But the evidence come from studies evaluating the ability to diagnose melanoma from images of lesions of a known diagnosis. We do not know yet where this evidence are applicable to a total body skin examination perform in a setting of profession's screening. Overall, information on the harms of melanoma screening is limited. Screening identifies non-melanoma skin cancer and probably thin melanoma with little or no potential for malignant spread and mortality. Some have suggested that the melanoma epidemic, which has surged roughly at the same time as the diffusion of skin cancer screening could in part be due to detection of thin and lesions. Research estimated the magnitude of over-diagnosis and over-treatment in MRI screening is clearly needed. On the point of over-diagnosis, I would like to briefly remind you that survival is not a good indicator of screening effectiveness. Survival of melanoma is substantially improved, because of the [INAUDIBLE] shift due to the detection of lesions with a more favorable prognosis is happened regardless of screening effectiveness. In fact, across European countries, survival correlate well with the intensity of early detection for melanoma, but is much less correlated with mortality for melanoma. What about the cost-effectiveness of screening? Modeling studies from different countries have consistently reported that melanoma screening can be cost-effective. Not only when screening adult groups, such as older men or those with a family history of melanoma, but although for the general population. One time screening through total body skin examination by dermatologist at age 50, has been found to be as cost-effective as screening strategies for breast or colorectal cancer. Economic analysis also suggest, given increasing incidence and in cost to manage melanoma, that melanoma prevention programs may even be cost-saving for governments in the near future. This would especially be the case if a primary prevention component is included in a screening strategy. Recent advances in imaging technologies are more and more used by physicians to aid visual inspections and improve melanoma detection. Three technologies are worth mentioning, dermoscopy, total body photography, and Smartphone applications. Dermoscopy is a non-invasive technique for a vivo observation of the skin zoom optic magnification. It enables these realizations of morphological structures that are invisible to the naked eye. Dermoscopy combined with visual inspection, is now the most widely used and studied diagnostic aid. In the hands of dermatologists and others, who frequently perform skin examinations. Dermoscopy increases the sensitivity of clinical evaluation for melanoma without significantly decreasing specificity. After appropriate training, dermoscopy also results in fewer excise benign lesions. Total body photography is still limited clinical evidence, creating images that can be electronically retrieved and analyzed. A laws to follow the dynamic evolution of melanocytic nevi and to detect minimal changes into first stages of melanoma development that cannot be seen with the naked eye or a dermoscope. Total body photography may complement dermoscopic evaluation and aid in skin self examination. Finally, Smartphone applications are the most widely available imaging modality for melanoma detection. These are cellphone programs that analyze self-taken photographs of suspicious lesions. Smartphone applications vary greatly in the diagnostic accuracy and are not yet deemed reliable for early detection of melanoma. Generally speaking, new diagnostic technologies for melanoma tend to substitute higher sensitivity for lower specificity. They appear to be more suited for screening high-risk subjects than the general population. I should also mention that several melanoma risk assessment aids have recently been developed. They are based on epidemiological risk factors to identify high risk subjects. These tools are statistical models that are primarily intended for clinicians to estimate the short term risk of melanoma for the patients. An interesting potentiality of using risk assessment aids, lies in the reduction by as much as 50% in the number needed to be screened to detect one melanoma. Is screening for melanoma recommended? The current evidence is insufficient to assess the balance of benefits and harms of visual skin examination by a clinician. Many public health agencies like the United States Preventative Services Task Force or the National Institute for Health and Care Excellence in the UK, do not recommend screening for melanoma. Apart from Germany, there's currently no population based screening program for melanoma. However, from a purely economic perspective and depending on a setting, one time vision inspections of the whole body may be as cost-effective as screening such disease widely adaptive for other common cancers. In conclusion, high-quality evidence that screening reduces mortality from melanoma is not available. And no randomized controlled trial for melanoma screening, but body visual inspection is likely in the near future. Screening leads to decreased melanoma thickness, and decreasing thickness correlates with decreasing mortality by direct evidence between screening and the multiple impact is lacking. Accumulated indirect evidence indicates that melanoma prevention overall can be effective in reducing mortality. But the contribution of primary and secondary prevention cannot be separated. Prevention strategy for melanoma should not rely on screening alone and include primary prevention. A combined approach should improve both effectiveness and efficiency. New imaging technologies, as adjunct to visual skin inspection and risk assessment tools can reduce unnecessary medical procedures. As these new technologies have a limited contribution for the prediction of thick melanoma, the potential lies more in reducing the harms than improving the benefits from screening. Thank you for watching this video. [MUSIC]
