Role of 18F-FDG-PET/CT in the initial staging of very high-risk Ewing Sarcoma in a prospective multicentric Phase II Study: Is there still a place for bone marrow sampling?

BACKGROUND: The Ewing Sarcoma Family of Tumors (ESFT) constitutes a group of rare malignancies, wherein approximately one-third of cases exhibit metastatic spread, particularly impacting prognosis when bone and/or bone marrow (BM) are involved. Primary extra-pulmonary metastatic ESFT often necessitates intensified therapeutic approaches. Accurate staging plays a pivotal role in clinical decision-making, with fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) currently serving as a non-invasive modality for assessing ESFT's BM extent. METHODS: In the French phase II COMBINAIR3 (NCT03011528) study, a comprehensive approach for patients with extra-pulmonary ESFT metastasis was evaluated. We prospectively compared the efficacy of PET/CT to BM aspiration and biopsy (BMAB) analysis in patients undergoing initial staging. RESULTS: Among the 42 patients analyzed (median age 14 y, 2:1 male/female ratio), 45% presented with pelvic primary tumors and 83% had bone/BM involvement at diagnosis. Our findings showed PET/CT had 100% specificity and 83.3% sensitivity in detecting initial BM involvement. Overall, PET/CT correctly classified 92.8% of patients, reaching 100% accuracy in patients identified with bone involvement, thus surpassing the standard BMAB. DISCUSSION: These results suggest that the conventional use of BMAB in the initial staging of high-risk ESFT patients can be omitted, promoting PET/CT as a non-invasive alternative, thus improving staging accuracy and treatment decisions in ESFT management.

Li-Fraumeni-associated osteosarcomas: The French experience.

PURPOSE: Describe clinical characteristics and outcome of Li-Fraumeni syndrome (LFS)-associated osteosarcomas. METHODS: TP53 germline pathogenic/likely pathogenic variant carriers diagnosed with osteosarcoma in France between 1980 and 2019 were identified via the French Li-Fraumeni database at Rouen University Hospital. Sixty-five osteosarcomas in 52 patients with available clinical and histological data were included. The main clinical characteristics were compared with data from National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) for patients of the same age group. RESULTS: Median age at first osteosarcoma diagnosis was 13.7 years (range: 5.9-36.7). Compared to unselected osteosarcomas, LFS-associated osteosarcomas occurred more frequently in patients less than 10 years of age (23% vs. 9%), and when compared with osteosarcomas in patients less than 25 years were characterized by an excess of axial (16% vs. 10%) and jaw sites (15% vs. 3%) and histology with predominant chondroblastic component and periosteal subtypes (17% vs. 1%). Metastases incidence (25%) was as expected in osteosarcomas. After the first osteosarcoma treatment, the rate of good histologic response (62%) and the 5-year progression-free survival (55%, 95% confidence interval [CI]: 42.6-71.1) were as expected in unselected series of osteosarcomas, whereas the 5-year event-free survival was 36.5% [95% CI: 25.3-52.7] due to the high incidence of second malignancies reaching a 10-year cumulative risk of 43.4% [95% CI: 28.5-57.5]. CONCLUSION: In osteosarcoma, young age at diagnosis, axial and jaw sites, histology with periosteal or chondroblastic subtype, and synchronous multifocal tumors should prompt suspicion of a germline TP53 mutation. Standard treatments are effective, but multiple malignancies impair prognosis. Early recognition of these patients is crucial for tailored therapy and follow-up.

Late toxicity comparison of alkylating-based maintenance regimen with cyclophosphamide (VAC) vs ifosfamide (VAI) in Ewing sarcoma survivors treated in the randomized clinical trial Euro-EWING99-R1 in France.

In Euro-EWING99-R1 randomized trial, cyclophosphamide was shown to be noninferior to ifosfamide in the consolidation of standard-risk Ewing sarcoma (SR-EWS) after a common induction with VIDE (vincristine-ifosfamide-doxorubicin-etoposide). We present the results of the late effects analysis of VAC (vincristine-dactinomycin-cyclophoshamide) vs VAI (vincristine-dactinomycin-ifosfamide) conducted in Euro-EWING99-R1 French cohort. Of 267 French randomized patients, 204 were alive and free-of-relapse at 5-years including 172 with available long-term follow-up data concerning cardiac, renal and/or gonadal functions (sex-ratio M/F = 1.3, median age at diagnosis = 14 years): 84 randomized in VAC (median cumulative doses: cyclophosphamide = 9.7 g/m2 , ifosfamide = 59.4 g/m2 ) and 88 in VAI (ifosfamide = 97.1 g/m2 ). With a median follow-up of 10 years (range = 5-17), five late relapses and five second malignancies were recorded. The 10-year event-free survival among 5-year free-of-relapse survivors was similar between VAC and VAI (93% vs 95%, P = .63). We estimated the 10-year cumulative probabilities of cardiac and kidney toxicities at 4.4% (95% confidence interval [95% CI] = 1.1%-7.6%) and 34.8% (95% CI = 26.8%-42.0%), respectively. Cardiac toxicity cumulative probability was similar in both arms, whereas kidney toxicity was higher in VAI (at 10 years, 43.0% vs 25.7%, P = .02), resulting from significant difference in glomerular toxicity (31.1% vs 13.1%, P < .01). At 10 years, gonadal toxicity was observed in 27% and 28% of pubertal men and women, respectively, without significant difference between VAC and VAI. Kidney and gonadal toxicities represent major issues in Euro-EWING99-R1, with significantly higher risk of kidney toxicities with VAI, without significant gonadal toxicity reduction. These results support the need to limit cumulative doses of both alkylating agents and to use mixed regimen as in VIDE-VAC or VDC/IE (vincristine-doxorubicin-cyclophoshamide/ifosfamide-etoposide).

Molecular and clinicopathologic characterization of pediatric histiocytoses.

The spectrum of somatic mutations in pediatric histiocytoses and their clinical implications are not fully characterized, especially for non-Langerhans cell histiocytosis (-LCH) subtypes. A cohort of 415 children with histiocytosis from the French histiocytosis registry was reviewed and analyzed for BRAFV600E . Most BRAFWT samples were analyzed by next-generation sequencing (NGS) with a custom panel of genes for histiocytosis and myeloid neoplasia. Of 415 case samples, there were 366 LCH, 1 Erdheim-Chester disease, 21 Rosai-Dorfman disease (RDD), 21 juvenile xanthogranuloma (JXG, mostly with severe presentation), and 6 malignant histiocytosis (MH). BRAFV600E was the most common mutation found in LCH (50.3%, n = 184). Among 105 non-BRAFV600E -mutated LCH case samples, NGS revealed mutations as follows: MAP2K1 (n = 44), BRAF exon 12 deletions (n = 26), and duplications (n = 8), other BRAF V600 codon mutation (n = 4), and non-MAP-kinase pathway genes (n = 5). Wild-type sequences were identified in 17.1% of samples. BRAFV600E was the only variant significantly correlated with critical presentations: organ-risk involvement and neurodegeneration. MAP-kinase pathway mutations were identified in seven RDD (mostly MAP2K1) and three JXG samples, but most samples were wild-type on NGS. Finally, two MH samples had KRAS mutations, and one had a novel BRAFG469R mutation. Rarely, we identified mutations unrelated to MAP-kinase pathway genes. In conclusion, we characterized the mutational spectrum of childhood LCH and clinical correlations of variants and subtypes. Variants responsible for JXG and RDD were not elucidated in more than half of the cases, calling for other sequencing approaches.

Extracranial germ cell tumours in children and adolescents: Results from the French TGM13 protocol.

BACKGROUND: Chemotherapy for non-seminomatous germ cell tumours (NSGCT) exposes to dose-dependent toxicities. The TGM13-NS protocol (EudraCT 2013-004039-60) aimed to decrease the chemotherapy burden compared to the previous TGM95 protocol while maintaining the 5-year event-free survival (EFS) at 80% or more. PROCEDURE: Patients less than 19 years of age with disseminated NSGCT were enrolled (May 2014 to May 2019) and stratified into four groups: two intermediate-risk (IR: localised tumour with low tumour markers [TM]) groups treated with VBP (vinblastine-bleomycin-cisplatin): three courses for IR1 (ovarian tumour any age/testis tumour less than or equal to 10 years) and four courses for IR2 (extragonadal tumour 10 years or less) groups, and two high-risk (HR: metastatic and/or high TM) groups treated with etoposide-cisplatin and either ifosfamide (VIP) or bleomycin (BEP): three courses for HR1 (ovarian tumour any age/testis tumour less than or equal to 10 years and low TM/testis tumour more than 10 years and very low TM) groups and four courses for HR2 (remainder) groups. RESULTS: One hundred fifteen patients were included: median age of 12.8 years (0.4-18.9); tumour sites: 44 ovaries, 37 testes and 34 extragonadal. The 5-year EFS and overall survival (OS) were 87% (95% CI: 80-92) and 95% (89-98), respectively (median follow-up: 3.5 years, range: 0.2-5.9), similar to those of the TGM95 protocol (5-year EFS 89% (84-93), 5-year OS 93% (89-95), p = .561). The 5-year EFS were 93% (95% CI: 80-98), 88% (71-95) and 79% (62-90) for ovarian, testicular and extragonadal tumours, respectively. The 5-year EFS varied (p = .02) according to the risk groups: 90% (66-97), 64% (30-85), 95% (72-99) and 87% (74-94) for IR1, IR2, HR1 and HR2, respectively. TM decline adjusted to tumour site, and alpha-fetoprotein (AFP) level revealed a prognostic impact of time to normalisation on EFS: HR = 1.03 (1.003-1.007). CONCLUSION: Risk-adapted and globally decreased chemotherapy burden maintains excellent outcomes, exclusive of the IR2 group, which warrants more intensive chemotherapy.

Pattern of relapse in pediatric localized extremity rhabdomyosarcomas correlated with locoregional therapies administered.

BACKGROUND: Treatment of extremity rhabdomyosarcomas (RMS) includes chemotherapy, surgery, and radiotherapy. Lymph node irradiation is recommended in the presence of regional node involvement at diagnosis. The aim of this study was to analyze the correlation between the pattern of relapse of non-metastatic extremity RMS and the initial therapies delivered. METHODS: All patients with localized extremity RMS prospectively treated in France in the MMT-95 and RMS-05 protocols were selected. Extent of disease and pattern of relapse were evaluated by clinical examination and imaging. RESULTS: We identified 59 patients with clinical characteristics corresponding to unfavorable prognostic factors. Twenty patients (34%) were considered to have lymph node involvement at diagnosis. Regional node biopsy was performed in 32 patients (54%) and modified the lymph node stage in 8 of the 59 patients (14%). Seventy-three percent of patients received radiotherapy. Fifty-two patients achieved first remission. Overall, 26 patients underwent complete tumor resection, 17 had R1 margins, and 5 were not operated due to early tumor progression. With a median follow-up of 82 months (range: 5-287), 18 relapses had occurred, at least locoregional in 12 cases. The 5­year local and nodal control rates were 73% (63-86%) and 86% (77-95%), respectively. Five-year progression-free and overall survival were 57% (95%CI [45-72%]) and 70% (95%CI [58-84%]), respectively. CONCLUSION: The main sites of extremity RMS relapse are locoregional. Nodal failures in non-irradiated fields are not uncommon. We recommend systematic biopsy of in-transit nodes, especially in alveolar RMS and/or RMS with regional positive nodes at diagnosis to ensure their negativity.

Long-term follow-up of children with risk organ-negative Langerhans cell histiocytosis after 2-chlorodeoxyadenosine treatment.

The nucleoside analogue, 2-chlorodeoxyadenosine (2CDA), was reported to be an active treatment for childhood Langerhans cell histiocytosis (LCH) without risk organ (RO-) involvement. However, we lack data on long-term effects of 2CDA treatment, including the disease reactivation rate, permanent sequelae and long-term tolerance. This study included 44 children from the French LCH registry, treated for a RO- LCH with 2CDA monotherapy (median number of six courses). The median age at the beginning of 2CDA was 3·6 years (range, 0·3-19·7 years) and the median follow-up after was 5·4 years (range, 0·6-15·1 years). Objective response to 2CDA was observed in 25 patients (56·8%), while six patients (13·6%) had stable disease and 13 patients (29·5%) exhibited progressive disease. Among patients without progression, only two experienced disease reactivation after 2CDA discontinuation. The five-year cumulative incidence of disease progression or reactivation after 2CDA therapy initiation was 34·3%. The lymphopenia reported in all cases [72% below absolute lymphocyte count (ALC) of 0·5 G/l], was addressed with appropriate prophylactic measures. Other toxicities above grade 2 were uncommon, and no second malignant neoplasm or neuropathy was reported. The five-year overall survival was 97·7%. In conclusion, we could confirm that 2CDA monotherapy was a beneficial long-term therapy for treating patients with RO- LCH. Appropriate management of induced immune deficiency is mandatory.

Agreement between clinicoradiological signs at diagnosis and radiohistological analysis after neoadjuvant chemotherapy of suspected Wilms tumor rupture: Consequences on therapeutic choices.

INTRODUCTION: According to SIOP criteria, every patient presenting with preoperative Wilms tumor (WT) rupture must receive abdominal radiotherapy. Neoadjuvant chemotherapy reduces tumor volume and is responsible for the development of peritumoral capsule formation, which can mask tumor rupture on histological analysis, while it was clinically or radiologically obvious at diagnosis. Yet, there are no protocol recommendations for this particular presentation. OBJECTIVES: Study the agreement between clinicoradiological signs and histological confirmation after neoadjuvant chemotherapy of suspected WT rupture and describe the therapeutic choices arising in consequence. METHODS: Descriptive retrospective study on a monocentric series of patients with WT between June 1991 and August 2017. RESULTS: Out of 71 patients, 28 presented with suspected tumor rupture. We observed good agreement between clinical and radiological signs of suspected rupture (κ coefficient: 0.67). However, we assessed poor agreement between these signs and histological conclusions after neoadjuvant chemotherapy (κ coefficient: 0.27). Only five patients with clinicoradiological signs were overtreated with radiotherapy while tumor rupture had been refuted after histological review. The notion of abdominal trauma and the presence of intraperitoneal effusion seemed to guide collegial decision to overtreat these patients. No statistical difference in survival between patients with and without suspicion of tumor rupture at diagnosis was observed. CONCLUSION: This study highlights the need for recommendations in case of discrepancy between radiological and histological signs of rupture at diagnosis and after neoadjuvant chemotherapy. A study with stronger statistical power is necessary to define criteria that would lead to optimization of treatment in this context.

Contribution of de novo and mosaic TP53 mutations to Li-Fraumeni syndrome.

BACKGROUND: Development of tumours such as adrenocortical carcinomas (ACC), choroid plexus tumours (CPT) or female breast cancers before age 31 or multiple primary cancers belonging to the Li-Fraumeni (LFS) spectrum is, independently of the familial history, highly suggestive of a germline TP53 mutation. The aim of this study was to determine the contribution of de novo and mosaic mutations to LFS. METHODS AND RESULTS: Among 328 unrelated patients harbouring a germline TP53 mutation identified by Sanger sequencing and/or QMPSF, we could show that the mutations had occurred de novo in 40 cases, without detectable parental age effect. Sanger sequencing revealed two mosaic mutations in a child with ACC and in an unaffected father of a child with medulloblastoma. Re-analysis of blood DNA by next-generation sequencing, performed at a depth above 500X, from 108 patients suggestive of LFS without detectable TP53 mutations, allowed us to identify 6 additional cases of mosaic TP53 mutations, in 2/49 children with ACC, 2/21 children with CPT, in 1/31 women with breast cancer before age 31 and in a patient who developed an osteosarcoma at age 12, a breast carcinoma and a breast sarcoma at age 35. CONCLUSIONS: This study performed on a large series of TP53 mutation carriers allows estimating the contribution to LFS of de novo mutations to at least 14% (48/336) and suggests that approximately one-fifth of these de novo mutations occur during embryonic development. Considering the medical impact of TP53 mutation identification, medical laboratories in charge of TP53 testing should ensure the detection of mosaic mutations.

Incidence and risk factors for clinical neurodegenerative Langerhans cell histiocytosis: a longitudinal cohort study.

Neurodegenerative (ND) complications in Langerhans cell histiocytosis (LCH) are a late-onset but dramatic sequelae for which incidence and risk factors are not well defined. Based on a national prospective registry of paediatric LCH patients, we determined the incidence rate of clinical ND LCH (cND-LCH) and analysed risk factors, taking into account disease extent and molecular characteristics. Among 1897 LCH patients, 36 (1·9%) were diagnosed with a cND-LCH. The 10-year cumulative incidence of cND-LCH was 4·1%. cND-LCH typically affected patients previously treated for a multisystem, risk organ-negative LCH, represented in 69·4% of cND-LCH cases. Pituitary gland, skin and base skull/orbit bone lesions were more frequent (P < 0·001) in cND-LCH patients compared to those without cND-LCH (respectively 86·1% vs. 12·2%, 75·0% vs. 34·2%, and 63·9% vs. 28·4%). The 'cND susceptible patients' (n = 671) i.e., children who had experienced LCH disease with pituitary or skull base or orbit bone involvement, had a 10-year cND risk of 7·8% vs. 0% for patients who did not meet these criteria. Finally, BRAFV600E status added important information among these cND susceptible patients, with the 10-year cND risk of 33·1% if a BRAFV600E mutation was present compared to 2·9% if it was absent (P = 0·002).

Use of new targeted cancer therapies in children: effects on dental development and risk of jaw osteonecrosis: a review.

New targeted cancer therapies such as bisphosphonates, denosumab, and bevacizumab are routinely used in adult for the past decades. Their introduction into pediatric medicine is more recent that means there is a paucity of data on long-term effects on dental development and on the risk of osteonecrosis of jaw. This study aimed to outline adverse effects of new targeted cancer therapies on oral cavity including dental abnormalities observed in pediatric population treated with these molecules and the risk of osteonecrosis of the jaw (ONJ). The impact of bisphosphonates and denosumab on bone remodeling (inhibition of osteoclasts) could interfere with teeth exfoliation and eruption processes, causing a tooth eruption delay. This hypothesis was confirmed, bisphosphonate-treated rats presented tooth eruption delay, and bisphosphonate therapy was associated with a mean delay of 1.67 years in tooth eruption in children with osteogenesis imperfecta. Another study showed that the inhibition of RANK/RANKL by denosumab was associated with a lack of tooth eruption in animals. Several animal studies reported that bisphosphonate could also induce dental abnormalities including defective amelogenesis and dentinogenesis in rats, but there is no evidence of such effects in children; only one case of enamel hypoplasia in a child treated for idiopathic arterial calcification with bisphosphate was reported. To date, there has been no reported case of ONJ in children treated with bisphosphonates, denosumab, or bevacizumab.

Langerhans cell histiocytosis: therapeutic strategy and outcome in a 30-year nationwide cohort of 1478 patients under 18 years of age.

The French national cohort of children with Langerhans cell histiocytosis (LCH) has included 1478 patients since it was established in 1983. LCH therapeutic strategies substantially changed in 1998, so we have divided the cohort into two 15-year periods. Starting in 1998, therapy duration increased from 6 to 12 months, repeated induction therapy was performed in cases showing a poor response to the first induction with vinblastine and steroids, and refractory disease in a risk organ (RO+) was treated with cladribine and cytarabine. A total of 483 (33%) patients were enrolled before 1998, and 995 (67%) after 1998. Five-year survival was 96·6% (95% confidence interval: 95·4-97·5%) overall, improving from 92% pre-1998 to 99% post-1998 (P < 0·001 adjusted to disease extent). This change was supported by an increase in 5-year survival from 60% to 92% in the RO+ group. Survival was particularly associated with cladribine and cytarabine among refractory RO+ patients. Disease reactivation was slightly less frequent after 1998, due to better enrolment of single-system patients, extended therapy duration, and more efficient second-line therapy. The crude rates of endocrine and neurological sequelae (the most frequent sequelae) appeared to improve over time, but this difference was not observed when the analysis was stratified by disease extent.

Dosimetric analysis of hearing loss after cranial radiation therapy in children: A single-institution study from the French national registry PediaRT.

PURPOSE: To identify dosimetric predictive factors of sensorineural hearing loss (SNHL) in children after cranial radiation therapy (RT) in a single institution using dosimetric data from the French National Registry PediaRT. METHODS AND MATERIALS: Complete audiological follow-up data were available for 44 children treated with cranial RT between 2014 and 2021 at our institution. The median age at the time of RT initiation was 9 years (range: 2-17 years). No children presented with hearing loss prior to treatment. SNHL was defined as a Chang ototoxicity grade ≥ 1a or higher. RESULTS: Median audiometric follow-up duration was 51 months. Seven children (16 %) developed SNHL with a median time to occurrence of 33 months (range, 18-46 months). The estimated SNHL cumulative rate at 2 years post-RT was 4,5% ± 3,1% and at 5 years was 21 % ± 7.2 %. Multiple Cox regression models showed that the association of the age at radiotherapy and the dosimetric values to the inner ear canal and cochlea were the most significant predictive factors of SNHL occurrence. No child who received less than 35 Gy on average to both cochleae (n = 26) suffered from SNHL, whereas the 5-year SNHL cumulative incidence for the children who received greater than or equal to 35 Gy on average to either cochlea (n = 18) was 51.8 % ± 15.1 %. CONCLUSION: Doses received by the inner ear canal and cochlea, associated with the age at RT initiation, are the main predictive factors for radiation-induced SNHL. A median dose to either cochlea over 35 Gy significantly increases the risk of SNHL and justify close audiometric monitoring to detect and equip hearing loss at an early stage.

Post-zygotic mosaicism of SMARCB1 variants in patients with rhabdoid tumors: a not so rare condition exposing to successive tumors.

BACKGROUND: Rhabdoid tumors (RT) are aggressive, rare tumors predominantly affecting young children, characterized by bi-allelic SMARCB1 gene inactivation. While most SMARCB1 alterations are acquired de novo, a third of cases exhibit germline alterations, defining Rhabdoid Tumors Predisposition Syndrome (RTPS1). With increased sensitivity of next-generation sequencing (NGS), mosaicisms in genes linked to genetic diseases are more detectable. This study focuses on exploring SMARCB1 germline alterations, notably mosaicism in blood samples of children with RT and in parents, using a custom NGS panel. METHODS: A cohort of 280 children and 140 parents with germline analysis was studied. Germline DNA from 111 children with RT and 32 parents were re-analyzed with a custom NGS panel with 1,500X average depth targeting the SMARCB1 gene to identify intragenic variants not detected with conventional low-sensitivity methods. Follow-up data was obtained for 77 patients. RESULTS: Nine previously undetected mosaicism cases were identified, totaling 17/280 patients with a mosaic variant (6.1%) in the cohort, with variant allele frequencies between 0.9% and 33%, thus highlighting the prior underestimation of its prevalence. Follow-up data showed that 4 out of 7 survivors with mosaic variants developed distinct novel tumors, two sharing SMARCB1 alterations with the initial tumor, emphasizing the potential clinical impact of SMARCB1 mosaicism. CONCLUSIONS: The hitherto underestimated rate of SMARCB1 mosaicism in RT underscores the need for optimized genetic counseling and oncological monitoring. The findings have significant medical implications, considering the dire prognosis of RT.

Chemo-immunotherapy with dinutuximab beta in patients with relapsed/progressive high-risk neuroblastoma: does chemotherapy backbone matter?

BACKGROUND: Addition of anti-GD2 antibodies to temozolomide-based chemotherapy has demonstrated increased antitumor activity and progression-free survival in patients with relapsed/progressive high-risk neuroblastoma. However, chemo-immunotherapy is not yet approved for this indication. This study presents the chemo-immunotherapy experience in patients with relapsed/progressive high-risk neuroblastoma treated within the off-label use program of the Neuroblastoma Committee of the French Society of Pediatric Oncology (SFCE). METHODS: Dinutuximab beta (dB) was administered alongside temozolomide-topotecan (TOTEM) or temozolomide-irinotecan (TEMIRI) at first disease relapse/progression or topotecan-cyclophosphamide (TopoCyclo) at further relapse/progression. Real-world data on demographics, treatment, antitumor activity and safety was collected from all patients after inclusion in SACHA-France (NCT04477681), a prospective national registry, which documents safety and efficacy data on innovative anticancer therapies prescribed to patients ≤ 25 years old as compassionate or off-label use. RESULTS: Between February 2021 and July 2023, 39 patients with confirmed relapsed/progressive high-risk neuroblastoma (median age 6 years, range 1-24) were treated with dB+TopoCyclo (n = 24) or dB+TOTEM/TEMIRI (n = 15) across 17 centers. In total, 163 chemo-immunotherapy cycles were administered, main toxicities were mild or moderate, with higher incidence of hematological adverse drug reactions with dB+TopoCyclo than dB+TOTEM/TEMIRI. Objective response rate was 42% for dB+TopoCyclo (CI95% 22-63%) and 40% for dB+TOTEM/TEMIRI (CI95% 16-68%). CONCLUSION: Similar objective response rates for dB+TopoCyclo and dB+TOTEM/TEMIRI in patients with relapsed/progressive high-risk neuroblastoma emphasize the importance of chemo-immunotherapy, irrespective of the chemotherapy backbone.

Sequential Analysis of cfDNA Reveals Clonal Evolution in Patients with Neuroblastoma Receiving ALK-Targeted Therapy.

PURPOSE: The study of cell-free DNA (cfDNA) enables sequential analysis of tumor cell-specific genetic alterations in patients with neuroblastoma. EXPERIMENTAL DESIGN: Eighteen patients with relapsing neuroblastoma having received lorlatinib, a third-generation ALK inhibitor, were identified (SACHA national registry and/or in the institution). cfDNA was analyzed at relapse for nine patients and sequentially for five patients (blood/bone marrow plasma) by performing whole-genome sequencing library construction followed by ALK-targeted ddPCR of the hotspot mutations [F1174L, R1275Q, and I1170N; variant allele fraction (VAF) detection limit 0.1%] and whole-exome sequencing (WES) to evaluate disease burden and clonal evolution, following comparison with tumor/germline WES. RESULTS: Overall response rate to lorlatinib was 33% (CI, 13%-59%), with response observed in 6/10 cases without versus 0/8 cases with MYCN amplification (MNA). ALK VAFs correlated with the overall clinical disease status, with a VAF < 0.1% in clinical remission, versus higher VAFs (>30%) at progression. Importantly, sequential ALK ddPCR detected relapse earlier than clinical imaging. cfDNA WES revealed new SNVs, not seen in the primary tumor, in all instances of disease progression after lorlatinib treatment, indicating clonal evolution, including alterations in genes linked to tumor aggressivity (TP53) or novel targets (EGFR). Gene pathway analysis revealed an enrichment for genes targeting cell differentiation in emerging clones, and cell adhesion in persistent clones. Evidence of clonal hematopoiesis could be observed in follow-up samples. CONCLUSIONS: We demonstrate the clinical utility of combining ALK cfDNA ddPCR for disease monitoring and cfDNA WES for the study of clonal evolution and resistance mechanisms in patients with neuroblastoma receiving ALK-targeted therapy.

Medulloblastomas with ELP1 pathogenic variants: A weakly penetrant syndrome with a restricted spectrum in a limited age window.

Background: ELP1 pathogenic variants (PV) have been recently identified as the most frequent variants predisposing to Sonic Hedgehog (SHH) medulloblastomas (MB); however, guidelines are still lacking for genetic counseling in this new syndrome. Methods: We retrospectively reviewed clinical and genetic data of a French series of 29 ELP1-mutated MB. Results: All patients developed SHH-MB, with a biallelic inactivation of PTCH1 found in 24 tumors. Other recurrent alterations encompassed the TP53 pathway and activation of MYCN/MYCL signaling. The median age at diagnosis was 7.3 years (range: 3-14). ELP1-mutated MB behave as sporadic cases, with similar distribution within clinical and molecular risk groups and similar outcomes (5 y - OS = 86%); no unusual side effect of treatments was noticed. Remarkably, a germline ELP1 PV was identified in all patients with available constitutional DNA (n = 26); moreover, all tested familial trio (n = 11) revealed that the PVs were inherited. Two of the 26 index cases from the French series had a family history of MB; pedigrees from these patients and from 1 additional Dutch family suggested a weak penetrance. Apart from MB, no cancer was associated with ELP1 PVs; second tumors reported in 4 patients occurred within the irradiation fields, in the usual time-lapse for expected radiotherapy-induced neoplasms. Conclusions: The low penetrance, the "at risk' age window limited to childhood and the narrow tumor spectrum, question the actual benefit of genetic screening in these patients and their family. Our results suggest restricting ELP1 germline sequencing to patients with SHH-MB, depending on the parents" request.

Thymus and mediastinal node involvement in childhood Langerhans cell histiocytosis: long-term follow-up from the French national cohort.

BACKGROUND: Mediastinal involvement (MI) in Langerhans cell histiocytosis (LCH) has been rarely reported. Here, we describe the clinical, radiological, and biological presentation, and the outcome of childhood LCH with MI. METHOD: From the French LCH register, which includes 1,423 patients aged less than 18 years, we retrieved the medical charts of patients with mediastinal enlargement detected on chest X-rays. RESULTS: Thirty-seven patients were retrieved, including 18 males; median age of diagnosis was 0.7 years, and median follow-up time was 6.2 years. The prevalence of MI varied with the age at diagnosis, ranging from 7% below 1 year old to less than 1% at >5 years. Thirteen cases (35%) were diagnosed because of MI-related symptoms, including respiratory distress (N = 4), superior venous cava syndrome (N = 2), and/or cough and polypnea (N = 10). CT scans performed in 32 cases at diagnosis showed tracheal compression (N = 5), cava thrombosis (N = 2), and/or calcification (N = 16). All patients presented multi-system disease at LCH diagnosis, and 35/37 were initially treated with vinblastine and corticosteroids. Death occurred in five cases, due to MI (N = 1) or hematological refractory involvement (N = 4). The overall 5-year survival was 87.1%, and immunodeficiency was not detected as a sequel. CONCLUSIONS: MI in LCH mainly occurs in young children, and diagnosis was based on CT showing thymus enlargement and calcifications.

Fertility discussions and concerns in childhood cancer survivors, a systematic review for updated practice.

PURPOSE: To provide ways to improve the clinical practice of fertility preservation (FP) for children, adolescents, and young adults (AYA) with cancer. DESIGN: A systematic research of online databases was undertaken in March 2020 following the PRISMA criteria, including Medline and Web of Science. RESULTS: Fifty-nine articles were included. Surveys, interviews, and focus groups were used to collect data from patients, parents, and health care providers (HCPs). Four themes worth exploring emerged: (a) what do patients and professionals think of and know about FP? (b) what makes the fertility discussion happen or not? (c) what, retrospectively, led to FP being pursued or not? and (d) how do patients and HCPs feel about fertility issues? CONCLUSION: A minority of AYAs preserve their fertility (banking assay for 45% of boys and 23% of girls). Yet fertility concerns have a significant impact on the quality of life of young cancer survivors. Although recommendations and guidelines regarding FP are available internationally, there are no specific guidelines as to how to conduct fertility counseling for children and adolescents. Some barriers are not removable, such as a poor prognosis of an obvious severe disease, time constraints for starting treatment, and cultural and religious beliefs. In response to aspects hindering patients and families to be receptive to any discussion at the time of diagnosis, psychological support could reduce the level of emotional distress and help restore a degree of open-mindedness to open a window for discussion. Moreover, as the lack of knowledge of professionals about fertility is frequently pointed out as a limiting factor for fertility discussion, reinforcing professional training regarding FP could be proposed to promote fertility discussion and eventually referral for FP.