PAX-FOXO1 fusion status in children and adolescents with alveolar rhabdomyosarcoma: Impact on clinical, pathological, and survival features.

BACKGROUND: Alveolar rhabdomyosarcoma (ARMS) is an aggressive pediatric cancer and cases with fusion PAX3-FOXO1 and PAX7-FOXO1 seem to have a poor prognosis. The aim is to evaluate whether PAX-FOXO1 alterations influence clinical outcome in childhood and adolescence population with ARMS. PROCEDURE: A population-based study was conducted between 2011 and 2016 in patients less than 17 years with a diagnosis of ARMS. Overall survival (OS) depending on fusion status with clinical factors was analyzed. RESULTS: Out of 111 ARMS patients recorded in the French National Childhood Cancer Registry during the 2011-2016 period, 61% expressed PAX3-FOXO1, 15% expressed PAX7-FOXO1, 13% were FOXO1 fusion-positive without PAX specification, and 7% were PAX-FOXO1 negative (n = 4 missing data). Compared to patients with PAX7-FOXO1 positive ARMS, those with PAX3-FOXO1 positive tumor were significantly older (10-17 years: 57.4% vs. 29.4%), and had more often a metastatic disease (54.4% vs. 23.5%). Poorer 5-year OS for patients with PAX3-FOXO1 and PAX not specified FOXO1-positive tumor were observed (44.0% [32.0-55.4] and 35.7% [13.1-59.4], respectively). After adjustment for stage at diagnosis, patients with positive tumor for PAX3-FOXO1 were 3.6-fold more likely to die than those with positive tumor for PAX7-FOXO1. CONCLUSION: At the population level, PAX3-FOXO1 was associated with a significant higher risk of death compared to PAX7-FOXO1-positive and PAX-FOXO1-negative tumors, and could explain poorer 5-year OS observed in adolescence population diagnosed with ARMS. A continuous risk score derived from the combination of clinical parameters with PAX3-FOXO1 fusion status represents a robust approach to improving current risk-adapted therapy for ARMS.

Cancer Among Adolescents and Young Adults Between 2000 and 2016 in France: Incidence and Improved Survival.

Purpose: This study was undertaken to determine cancer survival and describe the spectrum of cancers diagnosed among French adolescent and young adult (AYA) population. Methods: All cases of cancer diagnosed in 15-24 years, recorded by all French population-based registries (18% of the French population), over the 2000-2016 period, were included. Age-standardized incidence rates, conventional annual percentage change (cAPC) of incidence over time, and 5-year overall survival (5yOS) were calculated. Results: We analyzed 2734 cancer diagnoses in adolescents and 4199 in young adults. Overall incidence rates were 231.9/106 in 15-19 year olds and 354.0/106 in 20-24 year olds. The most frequently diagnosed cancers in male AYA were malignant gonadal germ-cell tumors (GCT), Hodgkin lymphoma (HL), and malignant melanoma and were HL, thyroid carcinoma, and malignant melanoma in females. Cancer incidence was stable over time with a cAPC of 0.8% (p = 0.72). For all cancers combined, 5yOS was 86.6% (95% CI: 85.8-87.4), >85% for HL, non-Hodgkin lymphomas (NHL), GCT, thyroid carcinomas, and malignant melanomas, and around 60% and lower for osteosarcomas, Ewing tumors, hepatic carcinomas, and rhabdomyosarcomas. The 5yOS has significantly improved from 2000-2007 to 2008-2015 for all cancers pooled, with a substantial gain of 4% for 15-19 year olds and 3% for 20-24 year olds. Conclusion: Notwithstanding the encouraging results for some cancers, and overall, persistent poorer survivals in AYA were shown compared to children for acute lymphoblastic leukemia, osteosarcoma, Ewing tumor, rhabdomyosarcoma, and malignant hepatic tumors. These disparities require further investigation to identify and address the causes of these inferior outcomes.