Response: cancer risk in chronic myeloproliferative neoplasms

We thank Susini and colleagues for their comments¹  to our article on the risk of a new cancer in patients with chronic myeloproliferative neoplasms (CMPNs).²  We have read the results from their CMPN cohort from Tuscany with interest. We agree that any novel finding must be confirmed before generally accepted and shared with patients. However, other studies have found results in line with ours. Fallah et al reported an increased risk of kidney cancer, melanoma and nonmelanoma skin cancer, as well as endocrine cancers among patients diagnosed with polycythemia vera (PV).³  Nielsen et al reported an increased risk of any cancer among JAK2 V617F mutation-positive persons from the general population.⁴  In their study most new malignancies were CMPNs but also solid tumors were reported.⁴  Although we cannot rule out an effect of diagnostic misclassification of CMPNs in our study it is reassuring that we found similar risk of a new cancer among patients with chronic myeloid leukemia (CML) among whom diagnostic misclassification seems unlikely. We also found the expected increased risks of new hematologic malignancies. Furthermore, our results were robust across stratification according to a previous or current diagnosis of chronic obstructive pulmonary disease. The excess risk of nonhematologic cancers in our study is modest, ranging from 1.2 to 1.6, and might only be detectable in larger studies.