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Cancers 14(5), 1261 (2022). doi:10.3390/cancers14051261, Published by MDPI, Basel

Background: Childhood cancer patients are at increased risk of second primary neoplasms (SPNs). We assessed incidence and risk factors for early SPNs with a focus on cancer predisposition syndromes (CPSs). Patients and methods: This cohort study used data from the Swiss Childhood Cancer Registry. We included patients with first primary neoplasms (FPNs) diagnosed before age 21 years from 1986 to 2015 and identified SPNs occurring before age 21. We calculated standardised incidence ratios (SIRs) and absolute excess risks (AERs) using Swiss population cancer incidence data, and cumulative incidence of SPNs. We calculated hazard ratios (HRs) of risk factors for SPNs using Fine and Gray competing risk regression. Results: Among 8074 childhood cancer patients, 304 (4%) were diagnosed with a CPS and 94 (1%) developed early SPNs. The incidence of SPNs was more than 10-fold higher in childhood cancer patients than the incidence of neoplasms in the general population (SIR = 10.6, 95% confidence interval [CI]: 8.7-13.1) and the AER was 179/100,000 person-years (CI: 139-219). Cumulative incidence of SPNs 20 years after FPN diagnosis was 23% in patients with CPSs (CI: 12-41%) and 2.7% in those without (CI: 2.0-3.6%). Risk factors for SPNs were CPSs (HR = 7.8, CI: 4.8-12.7), chemotherapy (HR = 2.2, CI: 1.1-4.6), radiotherapy (HR = 1.9, CI = 1.2-2.9), haematopoietic stem cell transplantation (HR = 1.8, CI: 1-3.3), and older age (15-20 years) at FPN diagnosis (HR = 1.9, CI: 1.1-3.2). Conclusion: CPSs are associated with a high risk of SPNs before age 21 years. Identification of CPSs is important for appropriate cancer surveillance and targeted screening.

Induction therapy for childhood acute lymphoblastic leukemia (ALL) traditionally includes prednisone; yet, dexamethasone may have higher antileukemic potency, leading to fewer relapses and improved survival. After a 7-day prednisone prephase, 3720 patients enrolled on trial Associazione Italiana di Ematologia e Oncologia Pediatrica and Berlin-Frankfurt-Munster (AIEOP-BFM) ALL 2000 were randomly selected to receive either dexamethasone (10 mg/m(2) per day) or prednisone (60 mg/m(2) per day) for 3 weeks plus tapering in induction. The 5-year cumulative incidence of relapse (± standard error) was 10.8 ± 0.7% in the dexamethasone and 15.6 ± 0.8% in the prednisone group (P < .0001), showing the largest effect on extramedullary relapses. The benefit of dexamethasone was partially counterbalanced by a significantly higher induction-related death rate (2.5% vs 0.9%, P = .00013), resulting in 5-year event-free survival rates of 83.9 ± 0.9% for dexamethasone and 80.8 ± 0.9% for prednisone (P = .024). No difference was seen in 5-year overall survival (OS) in the total cohort (dexamethasone, 90.3 ± 0.7%; prednisone, 90.5 ± 0.7%). Retrospective analyses of predefined subgroups revealed a significant survival benefit from dexamethasone only for patients with T-cell ALL and good response to the prednisone prephase (prednisone good-response [PGR]) (dexamethasone, 91.4 ± 2.4%; prednisone, 82.6 ± 3.2%; P = .036). In patients with precursor B-cell ALL and PGR, survival after relapse was found to be significantly worse if patients were previously assigned to the dexamethasone arm. We conclude that, for patients with PGR in the large subgroup of precursor B-cell ALL, dexamethasone especially reduced the incidence of better salvageable relapses, resulting in inferior survival after relapse. This explains the lack of benefit from dexamethasone in overall survival that we observed in the total cohort except in the subset of T-cell ALL patients with PGR. This trial was registered at www.clinicaltrials.gov (BFM: NCT00430118, AIEOP: NCT00613457).