Morbidity and childbirth in myeloproliferative neoplasms

Sammanfattning: Myeloproliferative neoplasms (MPN) are a family of chronic hematologic cancers, characterized by excess proliferation of myeloid cell lineages, or fibrosis of the bone marrow. Patients with MPN generally have a long expected survival. To elucidate morbidities during the disease course, e.g. second malignancies and infections, and outcome and prognosis of pregnancy and childbirth, we performed four large population-based cohort studies based on data from Swedish health registers, and compared outcomes to those of matched controls. We found that patients with MPN are at increased risk of second cancers, both solid and hematologic. The hazard ratio (HR) of developing a solid cancer was 1.6 (I.5-1.7), where skin cancers had the largest risk increase, but cancers of the brain, lung, pancreas, kidney and endocrine organs were also significantly increased. Patients with MPN also had a twofold risk of infections, HR 2.0 (1.9-2.0), leading to hospitalization or death compared to controls. An increase was evident in all subtypes of MPN, but significantly higher in patients with primary myelofibrosis. Among women with MPN, there were 342 pregnancies beyond gestational week 22/28 in women with MPN in Sweden 1973-2018. Preterm birth, in particular iatrogenic preterm birth, was significantly increased, but not thrombosis, bleeding or other obstetric complications. Low birthweight was similarly increased to preterm birth, but there was no increase in low birthweight babies in pregnancies with term delivery. The incidence of childbirth during the last decade was 12.2 per 100,000 childbirths. In women with MPN birthrates were reduced by 22%, HR 0.78 (0.67-0.90) compared to matched controls. In a subgroup analysis, the HR of childbirth was not reduced in patients with essential thrombocythemia. The rate of miscarriage was not statistically significantly increased, HR 1.25 (0.89-1.76.) Stillbirth was significantly more common in MPN patients prior to the MPN diagnosis, (p=0.013). In conclusion, there is significant morbidity in the MPN population, with increased risk of second cancers and infections. Pregnancy outcomes are generally better than previously anticipated, however there is an increased risk of preterm birth, and birthrates in MPN are lower than in the general population.