PolmoniAMO_INGL

17 PolmoniAMO possible to personalise lung cancer screening according to individual risk level, thus reducing the number of LDCT examinations without reducing the benefits of this procedure [40]. A personalised screening protocol would have less of an economic impact, both in terms of equipment used and the workload of the radiology staff involved. Although recent studies have assessed its feasibility and cost-effectiveness [43] and developed risk models to optimise the frequency of screening, screening for lung can- cer has not yet become standard clinical practice in our country and is not among the cancer screening services offered by the SSN. Several barriers prevent LDCT from being recognised as a valid and cost-effective screening tool: first and foremost, false positive rates and overdiagnosis . There is concern about the excess of false positives that could lead to the overtreatment of slow-growing, indolent nodules. However, the data emerging from the clinical studies tell us that in reality, false positive rates are strictly dependent on the lung nodule manage- ment/monitoring protocol used, varying from around 20% in the NLST study to 1-2% in the NELSON study, suggesting that optimisation and standardisation of shared protocols is essential to control and limit this issue. Moreover, the false positive rates are relatively low compared to the benefits of this screening method that increases the likelihood of curing a disease that would otherwise have an unfavourable outcome. Finally, it should not be forgotten that false positives are a common occurrence in cancer screen- ing: one in two mammography and one in four faecal occult blood tests give a false positive [44], but despite this these tests have long been recommended in at-risk populations in our country. Overdiagnosis is essentially linked to three factors: the presence of so-called indolent tumours, the inability of LDCT to differentiate between indolent and aggressive forms, and the significant likelihood that the eligible population will die of non-neoplastic caus- es (so-called competitive risk) before being diagnosed with a previously clinically silent cancer. If we consider that the population eligible for lung cancer screening predom- inantly consists of elderly and heavy smokers, who are also at high risk for other dis- eases, especially cardiovascular, we can at least partly account for the phenomenon of overdiagnosis associated with LDCT, which is certainly of a greater magnitude than that observed in women undergoing mammographies. There is no doubt that the number of false positives and overdiagnoses can be reduced by more accurately profiling and selecting the at-risk population. The failure to include LDCT in cancer screening is also the result of a prolonged lack of regional screening programmes for the early detection of lung cancer and an unwillingness by many regions to evaluate the feasibility of a screening pathway [45]. Where present, local screening initiatives refer to participation in the Dante and MILD studies and an observational study (Cosmos 1 and 2). These data testify to the