For each recruited case with concomitant diagnosis of myeloproliferative neoplasms (MPN) and secondary cancer each participating center will provide up 3 control patients (1 control for each case could be accepted but the optimal number is 3). Controls are patients with myeloproliferative neoplasms and no history of cancer. Each control will be matched to the paired case for sex, age (+/- 3 years), date of MPN diagnosis (+/- 5 years), and MPN disease duration (+/- 3 years).
Each control is censored at the date of the secondary cancer occurrence in his matched case (index date).
Data will be collected retrospectively from pre-existing medical records and reported by each center on a web-based and validated eCRF developed to record y all study data. In order to maintain patient privacy, all data records will be treated anonymously and no personal data to identify patient will be recorded: patients will be identified in the study by an alphanumeric code.