Risk of disease transformation and second primary solid tumors in patients with myeloproliferative neoplasms.

This study aimed to elucidate patterns of disease transformation to secondary myelofibrosis (SMF) or secondary acute myeloid leukemia (SAML) and the development of second primary malignancies in South Korean patients with BCR-ABL1-negative myeloproliferative neoplasms (MPNs). By using nationwide public health care insurance claims data, we identified and analyzed 7454 patients with MPNs who were newly diagnosed with essential thrombocythemia (ET), polycythemia vera (PV), or primary myelofibrosis (PMF) from 2008 to 2016 and used the data to appropriately trace the disease course. Transformation to SMF or SAML was rare in patients with ET and PV, but patients with PMF had an 8-year cumulative incidence of SAML of 21.4%. Patients with PV or ET had an 8-year cumulative incidence of second primary solid tumors of ∼14%. Patients with MPNs had a 2 times higher risk of developing second primary solid tumors than that of the general South Korean population. Compared with patients with PMF, patients with SMF had a similar overall survival with a lower risk of developing SAML. The use of ruxolitinib did not increase the risk of developing B-cell lymphoma over a median follow-up period of 16.2 months. Disease transformation to SMF or SAML was rare in patients with ET or PV, but SAML was common in patients with PMF. South Korean patients with MPNs had a significantly higher risk of developing second primary solid tumors than that of the general population, particularly for kidney, prostate, brain, liver, and lung cancers.