br Discussion The demographic and clinical characteristics o
Discussion The demographic and clinical characteristics of the assessed episodes are mostly consistent with the literature, particularly concerning patients’ age, neoplasm location and proportion of BCC and SCC [18,19]. However, for individual patients, the ratio NMSC:MM observed (7:1) was low, which might result from the fact that a high number of NMSC are treated in private institutions or left untreated. As expected, in-hospital mortality was higher for MM than NMSC episodes. Although we have no information regarding the death cause, these results are consistent with the higher metastatic rate found for MM episodes. On the other hand, although BCC is considered the most common malignancy in Caucasians, metastases are extremely rare (from 0.0028% to 0.55%) . It should be noted, however, that the proportion of metastatic episodes might have been overestimated (particularly concerning NMSC), as our study only comprises episodes occurred at public hospitals, where the most severe cases of Paxilline cancer are treated; in addition, some locally infiltrative basal cell carcinomas might have been wrongly classified as metastatic episodes. Interestingly, we found that, both for MM and NMSC, ageing associated with increased frequency of neoplasms in chronically exposed areas such the head and neck, but decreased proportions of trunk neoplasms. Although we provide an estimation of skin cancer hospital costs in Portugal, the reported values are probably underestimated, as this study has important limitations. In fact, this study does not take into account hospital costs of episodes occurring in private healthcare institutions; while most hospitalizations and ambulatory episodes occur in public hospitals, the role of private providers is expanding, particularly in the treatment of less severe conditions. The Public Portuguese Health System is overcrowded and the waiting list for diagnosis and treatment is usually long (6 months to 1 year or even more), as in other countries . Although it has not been yet quantified, it is common that patients without financial difficulties and/or with health insurance recur to private institutions for diagnosis and treatment, and are referred to public hospitals only in particular cases, mainly if additional treatment is needed. The majority of NMSC are not high-risk tumors and may be treated effectively at outpatient surgery center settings. Furthermore, in general, treatment of a malignant skin lesion is less expensive when done in an office or ambulatory surgical center than at a hospital [22,23]. We were not able either to assess costs other than hospital charges – this is particularly important for MM, which associates with substantial productivity losses [24,25]. Additionally, as with most skin cancer economic studies , the costs of precursor lesions (particularly, actinic keratosis, the precursor of SCC) are not being considered– assessing these lesions would be important to understand the possible impact of early detection and treatment. Notwithstanding, the costs reported are consistent with those in an administrative database study performed in Germany – we estimated average yearly hospital costs of 0.4 million € per million inhabitants for MM and 1.6 million € for NMSC; this compares with 0.6 million € for MM and 1.6 million € for NMSC in Germany . Therefore, despite its lower lethality, the economic impact of NMSC should not be underplayed - NMSC is one of the five most costly cancers to Medicare , accounting, according to our analysis, for 81% of all skin cancer costs (this is consistent with previous studies, which found NMSC cost to be up to 80% of all skin cancer costs) [23,29]. As with hospital costs, the incidence of skin cancer is also probably underestimated, as patients seeking care in private hospitals were not assessed. Nevertheless, our annual estimates surpass the projections for 2015 and 2020 by the Portuguese National Cancer Registry . In fact, cancer registries often underestimate the burden of skin cancer, as NMSC if often not reported, and registries do not consider multiple (synchronous or non-synchronous) primary tumors of the same histological group [27,31,32]. It should be noted, however, that, as data had been previously anonymized, individual patients in our studies were identified according to an algorithm based on patients’ hospital number, sex, birthdate and residence. Additional limitations of our study include lack of information regarding the severity of episodes, as well as the histological classification of NMSC prior to 2013. Finally, the ICD-9-CM codes used to identify MM and NMSC codes have not been validated in Portugal – nevertheless, an Italian study assessed the validity of the ICD-9-CM code 172.x (used to identify melanoma), finding a sensitvity close to 100% and positive predictive values ranging from 77% to 88% ; on the other hand, an American study found the ICD-9-CM code 173.x (used to assess NMSC) in administrative databases to have a positive predictive value of 60% (kappa statistic = 0.61) .