Children with progressive and relapsed pleuropulmonary blastoma: A European collaborative analysis

Background: Children with progressive (PD) or relapsed disease (RD) of pleuropulmonary blastoma (PPB) type II/III are known to have a very poor outcome. Methods: A retrospective review of children registered in national and European databases and trials (2000–2018) with diagnosis of PPB type II/III and PD or RD was performed. Results: A total of 35 patients with PPB were analysed: patients with PD (n = 9) and RD (n = 26). Patients experienced PD at the median age of 3.9 years [range, 0.5–17.8] despite surgery, chemotherapy (CHT, n = 9) and radiotherapy (RT, n = 1) with a median time to progression of 0.58 years [range, 0.02–1.27] from diagnosis. All of them died. Patients suffered from RD at the median age of 4.3 years [1.7–15.1], median delay to relapse 1.03 years [range, 0.03–2.95]. RD occurred locally (n = 12), combined (n = 1) and in metastatic sites (n = 13): central nervous system (n = 11) and unspecified site (n = 2). Patients were treated with salvage CHT (n = 20), surgery (n = 10) ± RT (n = 10). After a median follow-up of 4.2 years [range, 2.1–14.6], a second complete remission (CR) was achieved in nine out of 26 patients. Patients were alive in the second CR (n = 6), in the third CR (n = 1), in partial remission (n = 2) and lost of follow-up (n = 1). Five-year event-free survival (EFS) and overall survival (OS) for patients with RD were both 37% (±19, CI 95%). Local therapy (surgery, RT) had a favourable impact on OS (p = 0.03 and 0.02, respectively). Conclusions: Cure of patients with RD of PPB type II/III with multimodal treatment is possible but rare. Progressive PPB is fatal and patients need new treatment options.