Comment on ‘Validation of the diagnosis of mesothelioma and BAP1 protein expression in a cohort of asbestos textile workers from Northern Italy’
Authors: C. Brentisci, M. Gangemi, E. Migliore, D. Mirabelli, A. Stura
Journal: Annals of Oncology (2018)

In a recent paper, Boffetta et al. [1.Boffetta P. Righi L. Ciocan C. et al.Validation of the diagnosis of mesothelioma and BAP1 protein expression in a cohort of asbestos textile workers from Northern Italy.Ann Oncol. 2018; 29: 484-489Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar] reported on the results of their pathological revision of mesothelioma diagnoses among 127 decedents from a cohort of Italian asbestos-textile workers. Incidentally, they estimated that ‘sensitivity of the classification of the Registry (certain confirmed mesothelioma versus other) was 83% and the specificity 34%’. Such estimates question registration quality at the Registry of Malignant Mesotheliomas (RMM) of Piedmont, a collaborating centre of the Italian National Mesothelioma Registry, but cannot be checked based on the figures provided by the authors. On the authors’ request, in the framework of their study, we had carried out a record-linkage study between RMM and their case-series of decedents identifying 76 of them in our files, but even the individual data we were provided to this purpose are useless to replicate the calculations of sensitivity and specificity, as they did not include the results of diagnosis revision. Boffetta et al. could revise 35 cases confirming mesothelioma diagnosis in all, a reassuring finding as to quality of diagnosis in everyday practice. However, they did not specify how such cases overlapped with those linking with RMM records. If all were linked, RMM sensitivity would be 100%, rather than 83%. Boffetta et al. apparently considered only ‘certain’ cases in their calculations, excluding ‘probable/possible’ cases, which is incorrect as by such categories we classify only the basis of diagnosis [2.Nesti M. Adamoli S. Ammirabile F. et al.Guidelines for the Identification and Definition of Malignant Mesothelioma Cases and the Transmission to ISPESL by Regional Operating Centres. Monograph. ISPESL, Rome2003https://www.inail.it/cs/internet/docs/all-linee-guida-renam.pdf%3Fsection=attivitaGoogle Scholar]. If some of their 35 confirmed mesotheliomas were not found in RMM, we point out that cases falling outside the scope of RMM should be excluded from calculations. Based on year of death, place of residence and cause of death (as provided by Boffetta et al.), out of the 51 individuals unregistered by RMM no indication for registration existed for 21 residents outside Piedmont, 16 decedents before 1990 (year RMM started) and 6 mesothelioma-unrelated deaths. The remaining eight cases are under investigation. The 34% estimate for specificity would be of concern if justified. It is, however, not: as no mesothelioma diagnosis was rejected, no false positives could be present in RMM among revised cases. As for the remaining, unrevised cases, the authors had no evidence from ‘gold standard’ to rule out their original diagnoses. Finally, we were surprised by the statement that ‘low sensitivity in the classification of “certain” confirmed mesothelioma cases may affect population-based registries of mesothelioma which do not actively seek pathologic evidence’. At RMM cases are indeed identified by searching the records of all pathology laboratories serving Piedmont hospitals. Such search is carried out weekly in hospitals with a chest surgery unit—our rapid alert network. Two of Boffetta’s co-authors, as pathologists, have always been involved in the active identification of cases and granted us their precious collaboration. Moreover, we assisted the authors by providing access to RMM data for the 76 successfully linked cases, including pathology reports. Boffetta et al. were, thus, aware of our active search of cases and the data we collect as basis of diagnosis. None declared.