Defining and listing very rare cancers of paediatric age: consensus of the Joint Action on Rare Cancers in cooperation with the European Cooperative Study Group for Pediatric Rare Tumors

Characterization of PRAME immunohistochemistry reveals lower expression in pediatric melanoma compared to adult melanoma

Pediatric melanomas are rare tumors that have clinical and histological differences from adult melanomas. In adult melanoma, the immunohistochemical marker PRAME is increasingly employed as a diagnostic adjunct. PRAME is also under investigation as a target structure for next-generation immunotherapies including T-cell engagers. Little is known about the characteristics of PRAME expression in pediatric melanoma. In this retrospective study, samples from 25 pediatric melanomas were compared with control groups of melanomas in young adults (18-30 years; n = 32), adult melanoma (>30 years, n = 30), and benign melanocytic nevi in children (0-18 years; n = 30) with regard to the immunohistochemical expression of PRAME (diffuse PRAME expression >75%/absolute expression). Pediatric melanomas show lower diffuse PRAME expression (4%) and lower absolute PRAME expression (25%) compared to young adult melanomas (15.6%/46.8%) and adult melanomas (50%/70%). A significant age-dependent expression could be observed. An analysis of event-free survival shows no prognostic role for PRAME in pediatric melanoma and young adult melanoma, but a significant association with diffuse PRAME expression in adulthood. The age dependency of PRAME expression poses a potential pitfall in the diagnostic application of melanocytic tumors in young patients and may limit therapeutic options within this age group. The immunohistochemical expression of the tumor-associated antigen PRAME is an increasingly important diagnostic marker for melanocytic tumors and is gaining attention as a possible immunotherapeutic target in melanoma. As the available data primarily stem from adult melanoma, and given the clinical and histological distinctions in pediatric melanomas, our understanding of PRAME expression in this specific patient group remains limited. The age-dependent low PRAME expression shown here constrains the use of this marker in pediatric melanoma and may also limit the use of immunotherapeutic strategies against PRAME in young patients.

Expression of the tumor antigens NY-ESO-1, tyrosinase, MAGE-A3, and TPTE in pediatric and adult melanoma: a retrospective case control study

Tumor-associated antigens (TAAs) are potential targets for T cell-based immunotherapy approaches in cutaneous melanoma. BNT111, an investigational lipoplex-formulated mRNA-based therapeutic cancer vaccine encoding melanoma TAAs NY-ESO-1, tyrosinase, MAGE-A3, and TPTE, is undergoing clinical testing in adults. Expression of these TAAs in pediatric melanoma is unclear but is a prerequisite for feasibility of this treatment approach in children with melanoma. Our main objective was to characterize expression of those TAAs in pediatric melanomas compared to control cohorts. In this retrospective case control study, protein and transcript expression of NY-ESO-1, tyrosinase, MAGE-A3, and TPTE were analyzed in a cohort of 25 pediatric melanomas, 31 melanomas of young adults, 29 adult melanomas, and 30 benign melanocytic nevi in children using immunohistochemical staining and digital pathology (QuPath) and reverse transcription quantitative PCR. Based on IHC analysis, pediatric melanomas expressed tyrosinase (100.0%), TPTE (44.0%), MAGE-A3 (12.0%), and NY-ESO-1 (8.0%). Young adult melanomas expressed tyrosinase (96.8%), NY-ESO-1 (19.4%), MAGE-A3 (19.4%), and TPTE (3.2%). Adult melanomas expressed tyrosinase (86.2%), MAGE-A3 (75.9%), NY-ESO-1 (48.3%), and TPTE (48.3%). Childhood melanocytic nevi only expressed tyrosinase (93.3%). Expression prevalence of individual TAAs did not differ between subtypes of pediatric melanoma, and no association with prognosis was found. All four TAAs were expressed in pediatric melanoma, albeit NY-ESO-1 and MAGE-A3 to a lesser extent than in adult melanoma. These data support the possibility of investigating vaccines targeting these TAAs for the treatment of pediatric melanoma.

Unraveling molecular signatures in rare bone tumors and navigating the cancer pathway landscapes for targeted therapeutics

Rare cancers (RCs), which account for over 20% of cancer cases, face significant research and treatment challenges due to their limited prevalence. This results in suboptimal outcomes compared to more common malignancies. Rare bone tumors (RBTs) constitute 5-10% of rare cancer cases and pose unique diagnostic complexities. The therapeutic potential of anti-cancer drugs for RBTs remains largely unexplored. Identifying molecular alterations in cancer-related genes and their associated pathways is essential for precision medicine in RBTs. Small molecule inhibitors and monoclonal antibodies targeting specific RBT-associated proteins show promise. Ongoing clinical trials aim to define RBT biomarkers, subtypes, and optimal treatment contexts, including combination therapies and immunotherapeutic agents. This review addresses the challenges in diagnosing, treating, and studying RBTs, shedding light on the current state of RBT biomarkers, potential therapeutic targets, and promising inhibitors. Rare cancers demand attention and innovative solutions to improve clinical outcomes.

Nasopharyngeal Carcinoma in Children, Current Treatment Approach

Nasopharyngeal carcinoma (NPC) is a rare and locally aggressive form of childhood cancer. Treatment of pediatric NPC includes chemotherapy and radiotherapy. Most studies on the treatment of pediatric NPC are single-arm studies. With current treatment protocols survival rates for patients with nonmetastatic disease exceed 80%, although most children will have long-term treatment-related late effects. Efforts to reduce early and late toxicities include reduced radiotherapy doses in children with good responses to induction chemotherapy. Further studies are needed to evaluate the role of immunotherapy in both the primary setting and in children with progressive or relapsed disease. This review summarizes current clinical approaches to the treatment of pediatric NPC.

Regional lymph node evaluation in pediatric conventional melanoma subtype: a single-center 10-year review

PURPOSE

To assess the prognostic and therapeutic significance of sentinel lymph node biopsy (SLNB) and completion lymph node dissection (CLND) in pediatric conventional melanoma (CM), while evaluating potential predictive factors for outcomes.

METHODS

We conducted a retrospective analysis of medical records spanning 2009-2020, focusing on patients aged 18 or younger with localized cutaneous conventional melanoma.

RESULTS

Among the 33 patients, SLNB detected metastasis in 57.6% of cases, with 52.6% undergoing CLND. Positive SLN patients had higher relapse risk (HR 5.92; 95% CI 1.27-27.7; P = 0.024) but similar overall survival (HR 3.19; 95% CI 0.31-33.1, P = 0.33). No significant differences in disease-free survival (DFS) and OS were found between patients who underwent CLND and those who did not (HR 1.91; 95% CI 0.49-7.43, P = 0.35, and HR 0.52; 95% CI 0.03-8.32, P = 0.64, respectively). Univariate analysis showed age at diagnosis (P = 0.02) correlated with higher recurrence risk, with a 21% hazard increase per additional year of age.

CONCLUSIONS

Positive SLN status and age at diagnosis were associated with worse DFS in CM patients. Our study did not find any prognostic or therapeutic value in CLND for pediatric melanoma. Further multicenter trials are needed to confirm our single-institution experience.

LEVEL OF EVIDENCE

Level IV.

Histogram Analysis of Apparent Diffusion Coefficient Maps Provides Genotypic and Pretreatment Phenotypic Information in Pediatric and Young Adult Rhabdomyosarcoma

INTRODUCTION

We evaluate the role of apparent diffusion coefficient (ADC) histogram metrics in stratifying pediatric and young adult rhabdomyosarcomas.

METHODS

We retrospectively evaluated baseline diffusion-weighted imaging (DWI) from 38 patients with rhabdomyosarcomas (Not otherwise specified: 2; Embryonal: 21; Spindle Cell: 2; Alveolar: 13, mean ± std dev age: 8.1 ± 7.76 years). The diffusion images were obtained on a wide range of 1.5 T and 3 T scanners at multiple sites. FOXO1 fusion status was available for 35 patients, nine of whom harbored the fusion. 13 patients were TNM stage 1, eight had stage 2 disease, nine were stage 3, and eight had stage 4 disease. 23 patients belonged to Clinical Group III and seven to Group IV, while two and five were CG I and II, respectively. Nine patients were classified as low risk, while 21 and five were classified as intermediate and high risk respectively. Histogram parameters of the apparent diffusion coefficient (ADC) map from the entire tumor were obtained based on manual tumor contouring. A two-tailed Mann-Whitney U test was used for all two-group, and the Kruskal-Wallis's test was used for multiple-group comparisons. Bootstrapped receiver operating characteristic (ROC) curves and areas under the curve (AUC) were generated for the statistically significant histogram parameters to differentiate genotypic and phenotypic parameters.

RESULTS

Alveolar rhabdomyosarcomas had a statistically significant lower 10th Percentile (586.54 ± 164.52, mean ± std dev, values are in ×10-6mm2/s) than embryonal rhabdomyosarcomas (966.51 ± 481.33) with an AUC of 0.85 (95%CI. 0.73-0.95) for differentiating the two. The 10th percentile was also significantly different between FOXO1 fusion-positive (553.87 ± 187.64) and negative (898.07 ± 449.38) rhabdomyosarcomas with an AUC of 0.83 (95% CI 0.71-0.94). Alveolar rhabdomyosarcomas also had statistically significant lower Mean, Median, and Root Mean Squared ADC histogram values than embryonal rhabdomyosarcomas. Four, five, and seven of the 18 histogram parameters evaluated demonstrated a statistically significant increase with higher TNM stage, clinical group, assignment, and pretreatment risk stratification, respectively. For example, Entropy had an AUC of 0.8 (95% CI. 0.67-0.92) for differentiating TNM stage 1 from ≥ stage 2 and 0.9 (95% CI. 0.8-0.98) for differentiating low from intermediate or high-risk stratification.

CONCLUSION

Our findings demonstrate the potential of ADC histogram metrics to predict clinically relevant variables for rhabdomyosarcoma, including FOXO1 fusion status, histopathology, Clinical Group, TNM staging, and risk stratification.

Solid pseudopapillary neoplasms of the pancreas in childhood and adolescence-an analysis of the German Registry for Rare Pediatric Tumors (STEP)

Solid pseudopapillary neoplasms (SPNs) are the most common entity among pediatric pancreatic tumors. Still, these are rare tumors with an annual incidence of 0.1-0.2/1,000,000, and little is known about their optimal treatment. This analysis aimed to increase knowledge about the occurrence and treatment strategies of SPN in childhood. Data regarding diagnostics, treatment, and outcome of children aged 0-18 years with SPN recorded in the German Registry for Rare Pediatric Tumors (STEP) were analyzed. Thirty-eight patients were identified with a median age of 14.5 years at diagnosis (range: 8-18) and a female preponderance (81.6%). The most frequent location of the tumor was the pancreatic tail. In histopathological and immunohistochemical examination, pseudopapillary, solid, and cystic lesions as well as expression of beta-catenin, progesterone receptors, and cyclin D1 were the most common findings. All patients underwent surgical resection. Most patients underwent open resection, predominantly tail resection for tumors in the tail region and pylorus-preserving pancreaticoduodenectomy for tumors in the head region. The main postoperative sequela was exogenous pancreatic insufficiency (23.7%), especially with SPN in the pancreatic head. No recurrence occurred during follow-up, although two patients underwent resection with microscopic residue.

CONCLUSION

SPN of the pancreas in childhood are low-grade malignancies with usually favorable treatment outcomes. However, therapy can lead to relevant long-term sequelae. To prevent recurrence, complete surgical resection is recommended, sparing as much healthy pancreatic tissue as possible. Interdisciplinary collaboration between specialists is essential to optimize treatment. Molecular genetic analysis of these tumors could improve understanding of their genesis.

WHAT IS KNOWN

• Solid pseudopapillary neoplasms (SPNs) of the pancreas are very rare tumors in childhood. • Little is known about tumorigenesis, and there are no specific guidelines for treatment and follow-up in pediatric patients.

WHAT IS NEW

• Characteristics, treatment, and outcome were comprehensively assessed in a large cohort of pediatric patients with SPN. • We propose recommendations for diagnosis, treatment, and follow-up of children with SPN, based on our analysis and considering published experience.

Clinical Insight on Proton Therapy for Paediatric Rhabdomyosarcoma

This paper offers an insight into the use of Proton Beam Therapy (PBT) in paediatric patients with rhabdomyosarcoma (RMS). This paper provides a comprehensive analysis of the literature, investigating comparative photon-proton dosimetry, outcome, and toxicity. In the complex and multimodal scenario of the treatment of RMS, clear evidence of the therapeutic superiority of PBT compared to other modern photon techniques has not yet been demonstrated; however, PBT can be considered an excellent treatment option, in particular for young children and patients with specific primary sites, such as the head and neck area (and especially the parameningeal regions), genito-urinary, pelvic, and paravertebral regions. The unique depth-dose characteristics of protons can be exploited to achieve significant reductions in normal tissue doses and may allow an escalation of tumour doses and greater sparing of normal tissues, thus potentially improving local control while at the same time reducing toxicity and improving quality of life. However, access of children with RMS (and more in general with solid tumors) to PBT remains a challenge, due to the limited number of available proton therapy installations.

UV-radiation and MC1R germline mutations are risk factors for the development of conventional and spitzoid melanomas in children and adolescents

BACKGROUND

Genomic characterisation has led to an improved understanding of adult melanoma. However, the aetiology of melanoma in children is still unclear and identifying the correct diagnosis and therapeutic strategies remains challenging.

METHODS

Exome sequencing of matched tumour-normal pairs from 26 paediatric patients was performed to study the mutational spectrum of melanomas. The cohort was grouped into different categories: spitzoid melanoma (SM), conventional melanoma (CM), and other melanomas (OT).

FINDINGS

In all patients with CM (n = 10) germline variants associated with melanoma were found in low to moderate melanoma risk genes: in 8 patients MC1R variants, in 2 patients variants in MITF, PTEN and BRCA2. Somatic BRAF mutations were detected in 60% of CMs, homozygous deletions of CDKN2A in 20%, TERTp mutations in 30%. In the SM group (n = 12), 5 patients carried at least one MC1R variant; somatic BRAF mutations were detected in 8.3%, fusions in 25% of the cases. No SM showed a homozygous CDKN2A deletion nor a TERTp mutation. In 81.8% of the CM/SM cases the UV damage signatures SBS7 and/or DBS1 were detected. The patient with melanoma arising in giant congenital nevus (CNM) demonstrated the characteristic NRAS Q61K mutation.

INTERPRETATION

UV-radiation and MC1R germline variants are risk factors in the development of conventional and spitzoid paediatric melanomas. Paediatric CMs share genomic similarities with adult CMs while the SMs differ genetically from the CM group. Consistent genetic characterization of all paediatric melanomas will potentially lead to better subtype differentiation, treatment, and prevention in the future.

FUNDING

Found in Acknowledgement.

What rare cancers have in common. The making of lists of (very) rare cancers and the coordination of medical work

This article aims to understand why medical actors recently published lists of rare and very rare cancers. It studies four lists of rare and very rare cancers based on interviews with the main actors on these lists and an analysis of medical articles in which these lists were published. It argues that these lists constitute boundary objects whose aim is to deal with the organizational challenges raised by precision medicine, which imply increasing the coordination work between various types of actors. Our work therefore allows a better understanding of the functioning of the recursive standardization process of a boundary object and, by analyzing how the category of rarity is built at the intersection of both professional and nosographic principles, shows the intertwining of the biomedical, organizational, and political aspects on which rests the practice of contemporary precision medicine.

Imaging in rhabdomyosarcoma: a patient journey

Rhabdomyosarcoma, although rare, is the most frequent soft tissue sarcoma in children and adolescents. It can present as a mass at nearly any site in the body, with most common presentations in the head and neck, genitourinary tract and extremities. The optimal diagnostic approach and management of rhabdomyosarcoma require a multidisciplinary team with multimodal treatment, including chemotherapy and local therapy. Survival has improved over the last decades; however, further improvement in management is essential with current 5-year overall survival ranging from 35% to 100%, depending on disease and patient characteristics. In the full patient journey, from diagnosis, staging, management to follow-up after therapy, the paediatric radiologist and nuclear physician are essential members of the multidisciplinary team. Recently, guidelines of the European paediatric Soft tissue sarcoma Study Group, the Cooperative Weichteilsarkom Studiengruppe and the Oncology Task Force of the European Society of Paediatric Radiology (ESPR), in an ongoing collaboration with the International Soft-Tissue Sarcoma Database Consortium, provided guidance for high-quality imaging. In this educational paper, given as a lecture during the 2022 postgraduate ESPR course, the multi-disciplinary team of our national paediatric oncology centre presents the journey of two patients with rhabdomyosarcoma and discusses the impact on and considerations for the clinical (paediatric) radiologist and nuclear physician. The key learning points of the guidelines and their implementation in clinical practice are highlighted and up-to-date insights provided for all aspects from clinical suspicion of rhabdomyosarcoma and its differential diagnosis, to biopsy, staging, risk stratification, treatment response assessment and follow-up.

Epidemiology and Characteristics of Gastric Carcinoma in Childhood-An Analysis of Data from Population-Based and Clinical Cancer Registries

(1) Background: Gastric carcinoma is an exceptionally rare tumor in childhood. Little is known about the etiology, epidemiology, and clinical features of pediatric gastric carcinomas. This analysis aimed to fill this gap by increasing knowledge about the occurrence of gastric carcinoma in childhood. (2) Material and methods: Data from gastric carcinoma cases diagnosed between 2000 and 2017/2018 were retrieved from the Surveillance, Epidemiology, and End Results Program (SEER) and the German Center for Cancer Registry Data. Data from patients <20 years of age were analyzed for patient- and tumor-related characteristics. In addition, clinical data from patients with gastric carcinoma registered in the German Registry for Rare Pediatric Tumors (STEP) were analyzed for diagnostics, therapy, and outcome. (3) Results: Ninety-one cases of gastric carcinoma, mainly in adolescents, were identified in the epidemiologic cancer registries. Among patients with recorded staging data, advanced tumor stages were common (66.7%). Within the follow-up period covered, 63.7% of patients with clinical follow-up data died. Eight pediatric patients with gastric carcinoma were enrolled in the STEP registry, among whom two were patients with hereditary CDH1 mutations and another was a patient with Peutz−Jeghers syndrome. Three patients were found to have distinctly decreased immunoglobulin concentrations. All four patients in whom complete resection was achieved remained in remission. Three of the other four patients died despite multimodal therapy. (4) Conclusions: A combination of Helicobacter pylori infection and tumor predisposition and/or immunodeficiency appears to promote the development of gastric carcinoma in childhood. While patients with localized disease stages have a good chance of achieving durable remission through complete resection, patients with stage IV carcinomas face a dismal prognosis, highlighting the need to develop new strategies such as mutation-guided treatments.

Relapse after nonmetastatic rhabdomyosarcoma: Salvage rates and prognostic variables

BACKGROUND

Patients with relapsing rhabdomyosarcoma (RMS) pose a therapeutic challenge, and the survival rate is reportedly poor. We describe a retrospective series of relapsing RMS patients treated at a referral center for pediatric sarcoma, investigating the pattern of relapse, salvage rates, and factors correlating with final outcomes.

METHODS

The analysis concerned 105 patients <21 years old treated from 1985 to 2020 with initially localized RMS at first relapse. For risk-adapted stratification purposes, patient outcomes were examined using univariable and multivariable analyses based on patients' clinical features at first diagnosis, first-line treatments, clinical findings at first relapse, and second-line treatments.

RESULTS

First relapses occurred 0.08-4.8 years (median 1 year) following initial diagnosis and were local/locoregional in 59% of cases. Treatment at first relapse included chemotherapy in all but two cases, radiotherapy in 38, and surgery in 21. Median event-free survival (EFS) after first relapse was 4 months, while 5-year EFS was 16.3%; median overall survival (OS) was 9 months, while 5-year OS was 16.7%. Several variables influenced survival rates. Considering only clinical findings and treatment at relapse, Cox's multivariable analysis showed that OS correlated significantly with time to relapse, radiotherapy administered at relapse, response to chemotherapy, and whether a second remission was achieved.

CONCLUSION

Survival following first relapse of patients with localized RMS at initial diagnosis is poor. The variables found to influence survival can be utilized in a risk-adapted model to estimate the chances of salvage to guide decisions for second-line treatments.

The French FRACTURE database: A way to improve knowledge on management of children with very rare tumors

INTRODUCTION

Very rare pediatric tumors (VRTs), defined by an annual incidence ≤2 per million inhabitants, represent a heterogeneous group of cancers. Due to their extremely low incidence, knowledge on these tumors is scant. Since 2012, the French Very Rare Tumors Committee (FRACTURE) database has recorded clinical data about VRTs in France. This study aims: (a) to describe the tumors registered in the FRACTURE database; and (b) to compare these data with those registered in the French National Registry of Childhood Cancer (RNCE).

METHODS

Data recorded in the FRACTURE database between January 1, 2012 and December 31, 2018 were analyzed. In addition, these data were compared with those of the RNCE database between 2012 and 2015 to evaluate the completeness of the documentation and understand any discrepancies.

RESULTS

A total of 477 patients with VRTs were registered in the FRACTURE database, representing 97 histological types. Of the 14 most common tumors registered in the RNCE (772 patients), only 19% were also registered in the FRACTURE database. Total 39% of children and adolescent VRTs registered in the RNCE and/or FRACTURE database (323 of a total of 828 patients) were not treated in or linked to a specialized pediatric oncology unit.

CONCLUSION

VRTs represent many different heterogenous entities, which nevertheless account for 10% of all pediatric cancers diagnosed each year. Sustainability in the collection of these rare tumor cases is therefore important, and a regular systematic collaboration between the FRACTURE database and the RNCE register helps to provide a more exhaustive picture of these VRTs and allow research completeness for some peculiar groups of patients.

Surrogacy analysis of intermediate end-points for overall survival in randomized controlled trials of rhabdomyosarcoma

Treatment of malignant tumors, such as rhabdomyosarcoma (RMS), can improve overall survival (OS). It is time-consuming and expensive for patients to obtain benefits from randomized controlled trials (RCTs) with OS as the primary end-point. Therefore, another surrogate end-point is necessary; however, there is no report on the surrogacy analysis of RMS. In this study, we performed a systematic review of RCTs, involving patients with newly diagnosed RMS, and 11 RCTs were identified. We performed a meta-analysis to assess the surrogacy of intermediate end-points for OS. The correlations between surrogate end-points and OS were investigated using Spearman's rank correlation coefficient (ρ). The coefficient of determination (R²) was employed to measure the strength of the association. A total of 5183 patients were randomly allocated to 34 treatment groups. A marginal correlation (R² = 0.281, ρ = 0.445) between the hazard ratios (HRs) for event-free survival (EFS) and OS was observed. In patients with localized RMS, the EFS HR had a weaker correlation with OS HR in the sensitivity analysis than that in the primary analysis. Overall, the surrogacy of EFS for OS cannot be confirmed.

Metastatic rhabdomyosarcoma: Evidence of the impact of radiotherapy on survival. A retrospective single-center experience

BACKGROUND

The prognosis for patients with metastatic rhabdomyosarcoma (RMS) remains largely unsatisfactory despite the adoption of intensive multimodal therapy. To assess the role of different treatments adopted over the years, we retrospectively analyzed a cohort of patients &lt;21 years old with metastatic RMS, treated from 1990 to 2020 at a referral center for pediatric sarcomas.

METHODS

Patients were treated using a multimodal approach that included surgery, radiotherapy, and chemotherapy (both high-dose chemotherapy and maintenance therapy in some cases). The type of radiotherapy administered was categorized as radical (to all sites of disease); partial (to at least one, but not all sites of disease); or none. A landmark analysis was used to examine the impact of radiotherapy on survival, that is, patients who had an event before day 221 were excluded from the analysis.

RESULTS

The series included 80 patients. Event-free survival (EFS) and overall survival (OS) rates at 5 years were 17.3% and 21.3%, respectively. Survival was significantly associated with radiotherapy to metastatic sites, and with the radiotherapy category. In particular, 5-year EFS and OS rates were 70.6% and 76.0% for patients given radical radiotherapy, and 4.8% and 10.7%, respectively, for those given partial radiotherapy or none. Using the Cox multivariable analysis, OS correlated significantly with radiotherapy category.

CONCLUSIONS

While confirming the poor overall outcome of patients with metastatic RMS, this study identified radiotherapy-when given to all sites of disease (including metastases)-as the main variable influencing survival.

Successful Outcome of Metastatic Pancreatoblastoma in an Adolescent: A Case Report and Review of the Literature

Pancreatoblastoma, an orphan disease, is the most common malignant epithelial neoplasm of the pancreas in children. With vague clinical features, diagnosis is made by radiological suggestions and histopathology. The presence of metastatic disease and inoperable/incomplete excision remains the poor prognostic markers. We present a rare instance of an adolescent who has survived metastatic pancreatoblastoma after neoadjuvant chemoreduction/complete surgical excision.

Primary lung carcinoma in children and adolescents: An analysis of the European Cooperative Study Group on Paediatric Rare Tumours (EXPeRT)

BACKGROUND

Primary lung carcinoma is an exceptionally rare childhood tumour, as per definition of the European Cooperative Study Group on Paediatric Rare Tumours (EXPeRT), with an incidence of 0.1-0.2/1,000,000 per year. Little is known about the clinical characteristics of children with primary lung carcinoma, a gap which this joint analysis of the EXPeRT group aimed to fill.

PATIENTS AND METHODS

We performed a retrospective case series of children (aged 0-18 years) with primary lung carcinoma, as collected through the EXPeRT databases between 2000 and 2021. We recorded relevant clinical characteristics including treatment and outcome.

RESULTS

Thirty-eight patients were identified with a median age of 12.8 years at diagnosis (range: 0-17). Mucoepidermoid carcinoma (MEC) was the most frequent entity (n = 20), followed by adenocarcinoma (n = 12), squamous cell carcinoma (n = 4), adenosquamous carcinoma (n = 1) and small-cell lung cancer (n = 1). Patients with MEC presented rarely with lymph node metastases (2/20 cases). Overall, 19/20 patients achieved long-lasting remission by surgical resection only. Patients with other histologies often presented in advanced stages (14/18 TNM stage IV). With multimodal treatment, 3-year overall survival was 52% ± 13%. While all patients with squamous cell carcinoma died, the 12 patients with adenocarcinoma had a 3-year overall survival of 64% ± 15%.

CONCLUSIONS

Primary lung carcinomas rarely occur in children. While the outcome of children with MEC is favourable with surgery alone, patients with other histotypes have a poor prognosis, despite aggressive treatment, highlighting the need to develop new strategies for these children, such as mutation-guided treatment.

Incidences and characteristics of primary lung malignancies in childhood in Germany: An analysis of population-based data from German cancer registries

BACKGROUND

Primary lung malignancies are a heterogeneous group of cancers that occur very rarely in childhood. Due to limited knowledge of their epidemiologic and clinical features, these tumors present a challenge to the treating physicians. This study aimed to increase the knowledge about the occurrence of primary lung malignancies in childhood in Germany.

MATERIALS AND METHODS

Pseudonymized data of cases recorded at the German Center for Cancer Registry Data (ZfKD) between 1990 and 2017 were retrieved. Primary lung malignancies were identified using the ICD- and ICD-O classification. Numbers were compared to those reported to the German Childhood Cancer Registry (GCCR). Crude incidence rates were calculated using the ZfKD database.

RESULTS

A total of 168 patients diagnosed with primary lung malignancies in the age below 19 years were identified from the ZfKD. The median age at diagnosis was 13 years. The most common tumor entities were lung carcinoids (n = 49), lung carcinoma (n = 36), and pleuropulmonary blastoma (n = 14). An unexpected accumulation of lung cancer cases was noted in the first year of life without a clearly specified histopathological diagnosis. A substantial discrepancy in the numbers of primary lung malignancies between ZfKD and GCCR was found.

CONCLUSIONS

We present population-based data on the occurrence of primary childhood lung malignancies in Germany, which were more frequent than previously anticipated but likely remained underreported. For better understanding and optimal treatment of these entities, cancer registration needs to be improved through mandatory reporting to the GCCR and regular data sharing between GCCR, population-based and clinical cancer registries.

Adolescents and young adults with rhabdomyosarcoma treated in the European paediatric Soft tissue sarcoma Study Group (EpSSG) protocols: a cohort study

BACKGROUND

Adolescent and young adult patients with rhabdomyosarcoma often have poorer outcomes than do children. We aimed to compare the findings of adolescent and young adult patients with children enrolled in two prospective clinical protocols.

METHODS

This retrospective observational analysis was based on data from the European paediatric Soft tissue sarcoma Study Group (EpSSG) rhabdomyosarcoma 2005 trial (phase 3 randomised trial for localised rhabdomyosarcoma, open from April, 2006, to December, 2016) and the EpSSG MTS 2008 protocol (prospective, observational, single-arm study for metastatic rhabdomyosarcoma, open from June, 2010, to December, 2016), which involved 108 centres from 14 different countries in total. For this analysis, patients were categorised according to their age into children (age 0-14 years) and adolescents and young adults (age 15-21 years). For the analysis of adherence to treatment and toxicity, only patients with high-risk localised rhabdomyosarcoma included in the randomised part of the rhabdomyosarcoma 2005 study were considered. The primary outcome of event-free survival (assessed in all participants) was defined as the time from diagnosis to the first event (eg, tumour progression, relapse) or to the latest follow-up. Secondary outcomes were overall survival, response to chemotherapy, and toxicity.

FINDINGS

Our analysis included 1977 patients, 1720 children (median age 4·7 years; IQR 2·6-8·4) and 257 adolescents and young adults (16·6 years; 15·8-18·0). 1719 patients were from the EpSSG rhabdomyosarcoma 2005 study (1523 aged <15 years and 196 aged 15-21 years) and 258 patients were from the EPSSG MTS 2008 study (197 aged <15 years and 61 aged 15-21 years). Adolescent and young adult patients were more likely than were children to have metastatic tumours (61 [23·7%] of 257 vs 197 [11·5%] of 1720; p<0·0001), unfavourable histological subtypes (119 [46·3%] vs 451 [26·2%]; p<0·0001), tumours larger than 5 cm (177 [68·9%] vs 891 [51·8%]; p<0·0001), and regional lymph node involvement (109 [42·4%] vs 339 [19·7%]; p<0·0001). Adolescent and young adult patients had lower 5-year event-free survival (52·6% [95% CI 46·3-58·6] vs 67·8% [65·5-70·0]; p<0·0001) and lower 5-year overall survival (57·1% [50·4-63·1] vs 77·9% [75·8-79·8]; p<0·0001) than did children. The multivariable analysis confirmed the inferior prognosis of patients aged 15-21 years (hazard ratios 1·48 [95% CI 1·20-1·83; p=0·0002] for poorer event-free survival and 1·73 [1·37-2·19; p<0·0001] for poorer overall survival). Modifications of administered chemotherapy occurred in 13 (15·3%) of 85 adolescents and young adults, and in 161 (21·4%) of 754 children. Grade 3-4 haematological toxicity and infection were observed more frequently in children than in adolescent and young adult patients.

INTERPRETATION

This study found better outcomes for adolescent and young adult patients than those reported in epidemiological studies (eg, the EUROCARE-5 study reported 5-year overall survival of 39·6% for patients aged 15-19 years in the 2000-07 study period), suggesting that adolescent and young adult patients, at least up to age 21 years, can be treated with intensive paediatric therapies with no major tolerability issues and should be included in paediatric rhabdomyosarcoma trials. However, the inferior outcomes in adolescent and young adult patients compared with those in children, despite receiving similar therapy, suggest that a tailored and intensive treatment strategy might be warranted for these patients.

FUNDING

Fondazione Città della Speranza.

Accounting for the rarity of the disease when designing clinical trials with a focus on pediatric cancers

BACKGROUND

Clinical trials are challenging in rare diseases like pediatric cancers, where the accrual is limited. In these trials, inference assumptions are the same as in common diseases, that is the sample comes from a quasi-infinite population. This leads to overestimating the variance of the mean treatment effect. The finite-population correction factor correcting this bias is often used in surveys, but not in clinical trials. With few assumptions, the use of this correction factor can improve trials efficiency, showing that the power of those trials is sometimes higher than it appears.

METHODS

First, a simulation study assesses the standard error of the mean treatment effect and coverage of the 95% confidence interval with and without the correction. Second, the analytical power of a z-test with and without the correction is given. Finally, the impact on the sample size calculation is investigated. The impact of assuming a finite population is assessed for varying treatment effect, sample size and population size.

RESULTS

The simulation results confirm the overestimation of the standard error without the correction factor. When using the correction factor, the gain in power reaches up to 10.1%, 15.3% and 12.3% to detect a difference in treatment effect of 10%, 15% and 20%, respectively. The gain is negligible for n = 30, in scenarios with high power (>95%), and for large populations. This gain in power translates into a decrease in sample size: if the conventional calculation leads to a sample size 10% of the population size, then the sample size can be divided by 1.1; if the conventional calculation leads to a sample size 20% of the population size, then the sample size can be divided by 1.2, in order to reach the planned type I error and power.

CONCLUSION

When dealing with rare diseases like pediatric cancers, the power of clinical trials might be higher than it appears if using conventional sample sizes. When correcting the variance of the mean using the population size, a gain in efficiency is observed with reasonable sample sizes and treatment differences for very small population sizes, showing that this approach can be useful for some pediatric cancer clinical trials.

Rare pediatric tumors in Germany - not as rare as expected: a study based on data from the Bavarian Cancer Registry and the German Childhood Cancer Registry

Very rare pediatric tumors (VRTs) pose a challenge for treating physicians as little is known about the best diagnostic assessment and therapeutic decision-making in these malignancies. A large proportion of these cancers occur in adolescence. Therefore, the established structures of pediatric oncology including cancer registration may partly be circumvented. This may lead to an underregistration in clinical cancer registries of yet unclear extent. The aim of this study is to increase the knowledge on the occurrence of VRTs in pediatric patients in Germany. Pseudonymized data of cases recorded in the Bavarian Cancer Registry (BCR) between 2002 and 2014 were retrieved. VRTs according to the definition of the European Cooperative Study Group for Pediatric Rare Tumors were identified using the ICD and ICD-O classification. The numbers of registered patients were compared to those reported to the German Childhood Cancer Registry (GCCR). 6.3% (n = 290) of all malignancies (n = 4615) in the age below 18 years were classified as VRTs. Median age at diagnosis was 15 years (range 0-17 years). The most common tumor types included malignant melanoma, skin carcinoma, and gonadal tumors. During the same period, 49 pediatric patients from Bavaria with matchable VRTs were reported to the GCCR, accounting for 17% of cases reported to the BCR.

CONCLUSIONS

The frequency of VRTs in Germany is underestimated in the national GCCR. With this study, we present population-based data on the incidence of VRTs in Germany for the first time. In order to gain additional knowledge about these malignancies, registration of VRTs must be improved through enhanced data exchange between the GCCR, the public cancer registries, and the clinical Registry for Rare Pediatric Tumors (STEP).

WHAT IS KNOWN

• Rare pediatric tumors pose a challenge for treating physicians as limited knowledge is available on these malignancies for diagnostic and therapeutic decision-making. • Little is known about the frequency of these rare tumors in pediatric patients.

WHAT IS NEW

• The frequency of rare pediatric tumors in Germany is distinctly underestimated in the German Childhood Cancer Registry. • We present population-based data on the incidence of these rare pediatric cancers for the first time.

Role of centers with different patient volumes in the management of rhabdomyosarcoma. An analysis by the Italian Pediatric Soft Tissue Sarcoma Committee

PROCEDURE

The survival of children with rhabdomyosarcoma (RMS) has gradually improved as a result of the adoption of multidisciplinary treatments. Dedicated skills and facilities are indispensable and more readily available at reference centers. In this study, we examined the role of centers' experience (based on the number of patients treated) in their management of patients with RMS.

METHODS

We analyzed 342 patients with localized RMS enrolled in the European RMS 2005 protocol from October 2005 to December 2016 at 31 Italian centers that are part of the Soft Tissue Sarcoma Committee (STSC). We grouped the centers by the number of patients each one enrolled (Group 1: >40; Group 2: <40 and >10; and Group 3: <10), and compared a number of indicators to assess the appropriateness of patients' diagnostic workup and treatment and their survival.

RESULTS

Overall, 74.6% of patients were treated at 10 centers, and only three of them classifiable as high-volume centers. Only minor differences emerged between the three patient groups in terms of diagnostic investigations and treatment modalities. Survival was similar in the three groups. Approximately, one in four children treated at the centers in Groups 2 and 3 traveled to another center for surgery or radiotherapy.

CONCLUSION

Patients treated at STSC centers with different amounts of experience had similar results in terms of survival. This is attributable to all centers in the network adhering to protocol recommendations and receiving the STSC's support on diagnostics and multidisciplinary treatments for RMS.

Rare Tumors in Children and Adolescents - the STEP Working Group's Evolution to a Prospective Registry

Background Very rare tumors (VRT) in children and adolescents have such a low incidence that until recently, they have not been integrated into the clinical and scientific network of pediatric oncology. Data is very limited and consistent treatment strategies are missing. Thus, VRTs are classic orphan diseases. To counteract this problem, the Arbeitsgemeinschaft für Seltene Tumorerkrankungen in der Pädiatrie (STEP) was founded. Here we report on patient recruitment during the first 10 years. Patients Patients aged up to 18 years and not included in any other clinical trial or GPOH registry were included in this analysis. Methods Data was collected from 2008 to 2018 by means of a standardized form. The recorded diagnoses were descriptively analyzed focusing on histology, localization, and year of report. Results A total of 623 patients with VRTs were registered. During 2008-2014, the annual number of registrations was around 40 and is around 90 since 2015. Most frequent diagnoses included tumors of the skin (n=150), tumors of the gastrointestinal tract (n=102), tumors of the gonads (n=77), the ENT region (n=68), and miscellaneous tumors (n=107). Discussion With the establishment of central structures for clinical consultation and documentation of VRTs, the number of registrations increased. Comprehensively, VRTs are as common as other classic pediatric oncology tumors, but extremely heterogeneous in terms of localization, histology, and prognosis. By a centralized and complete registration and analysis of VRTs, also in collaboration with international partners, it is possible to develop treatment strategies and thus greatly increase treatment quality.

Primary lung carcinoma in children and adolescents - Clinical characteristics and outcome of 12 cases from the German registry for rare paediatric tumours (STEP)

OBJECTIVES

Primary lung carcinomas are very rare paediatric tumours with an incidence of < 2/1.000.000 per year. They are clinically and histologically heterogeneous, and there are no therapeutic guidelines for this age group. Therefore, they represent a challenge for treating physicians. This analysis was performed to expand knowledge on characteristics, treatment and prognosis of primary lung carcinoma in paediatric patients.

MATERIAL AND METHODS

Between 2009 and 2019, twelve children and adolescents with lung carcinoma were identified in the prospective German registry for rare paediatric tumours (STEP). Data were analysed for histopathological entities, symptoms, diagnostics, therapy, clinical course and outcome.

RESULTS

Mucoepidermoid carcinoma (MEC) was the most frequent entity (n = 7), followed by adenocarcinoma (n = 2), squamous cell carcinoma (SCC; n = 2) and adenosquamous carcinoma (n = 1). Patients presented with non-specific symptoms and often, they were initially mistreated for airway infections. Patients with MEC showed no metastases and were successfully treated with complete resection. Patients with adenocarcinoma and SCC were older than 16 years of age at diagnosis. While patients with SCC presented with distant metastases and died within one year after diagnosis, those with adenocarcinoma and adenosquamous carcinoma achieved complete remission after multimodal treatment.

CONCLUSIONS

Presenting symptoms of lung carcinomas are unspecific and therefore, diagnostic evaluation and treatment are difficult. In the absence of carcinogen exposure, etiology seems to differ from adult lung carcinoma. Children diagnosed with MEC face a favourable outcome. In contrast, patients with prognostically unfavourable adenocarcinoma and SCC might benefit from molecular profiling and targeted therapies. International collaboration for the establishment of treatment protocols adjusted for distinct features of primary lung carcinoma in childhood is essential.

Controversies on the possible role of immune checkpoint inhibitors in pediatric cancers: balancing irAEs and efficacy

Pediatric cancers are not the equivalent of adult cancers occurring at a younger age and the prospect of immunotherapy in children has not been received with the same enthusiasm as in the adult setting. Although most pediatric malignancies are considered immunologically cold, we are learning more about PD-L1 expression, tumor mutational burden, and microsatellite instability in several pediatric cancers. The side effects of immunotherapy are an important consideration. Immune checkpoint inhibitors (ICIs) engender a unique constellation of inflammatory toxicities known as immune-related adverse events (irAEs). Three early-phase trials-KEYNOTE-051, iMATRIX, and ADVL1412-were the first to describe irAEs in pediatric patients and ICIs were well tolerated. There was concern about unknown late irAEs in pediatric patients, as they have much more time to develop than in adult or elderly patients. Academic clinicians, biopharmaceutical companies, and parents' advocates concluded that no benefit could be expected from further monotherapy trials employing other ICIs with the same mechanism of action until more scientific knowledge becomes available. On the other hand, ICIs could be useful in combination with other therapies to prevent the functional inactivation of several pathways in the hostile microenvironment. Future clinical studies on ICIs in children need to build on strong biological premises, taking into account the distinctive immunobiology of pediatric cancers vis-à-vis ICI-responsive adult cancers. We need to gain and share experiences of new therapies for managing pediatric patients with cancer, clarifying to what extent we can extrapolate the data obtained in adults.

The impact of incomplete registration on survival rate of children with very rare tumors

Pediatric very rare tumors (VRTs) represent a heterogeneous subset of childhood cancers, with reliable survival estimates depending dramatically on each (un)registered case. The current study aimed to evaluate the number of VRTs among Lithuanian children, to assess the impact of the registration status on survival rates and to track changes in treatment outcomes over the 16-year study period. We performed a population-based retrospective study across children below 18 years old diagnosed with VRTs in Lithuania between the years 2000 and 2015. The identified cases were cross-checked with the Lithuanian Cancer Registry—a population-based epidemiology cancer registry—for the fact of registration and survival status. The overall survival was calculated in relation to the registration status and treatment period. Thirty-seven children with VRTs were identified within the defined time frame. Six of them (16.2%) were not reported to the Lithuanian Cancer Registry at diagnosis. The probability of overall survival at 5 years (OS_5y) differed significantly between the registered (n = 31) and unregistered (n = 6) cohorts: 51.6% versus 100%, respectively (p = 0.049). A 5-year survival estimate for children diagnosed with a VRT at the age of 0–14 years differed by 10 percentage points according to the registration completeness: 52.1% calculated for the entire cohort versus 42.1% for registered patients only. The OS_5y has not improved over the analyzed period: 61.1% in 2000–2007 versus 57.9% in 2008–2015 (p = 0.805). The survival continued to decline beyond 5 years post-diagnosis due to late cancer-related adverse events: 59.5% of patients were alive at 5 years as compared to 44.3% at 10 years. The OS_5y of children affected by VRT was lower than in more common childhood cancers. The survival rate of the unregistered patients may lead to misinterpretation of treatment outcomes. Meticulous registration of VRTs is crucial for correct evaluation of treatment outcomes, especially across small countries with few cases.

Complexity index in sarcoma and genomic grade index gene signatures in rhabdomyosarcoma of pediatric and adult ages

BACKGROUND

Rhabdomyosarcoma (RMS), the most frequent soft-tissue sarcoma in childhood, shows extensive heterogeneity in histology, site and age of onset, clinical course, and prognosis. Adolescents and young adults (AYA) with RMS form a subgroup of patients whose survival lacks behind that of children while diagnosed with histologically similar tumors.

PROCEDURES

A 67-gene prognostic signature related to chromosome integrity, mitotic control, and genome complexity in sarcomas (CINSARC) is considered a powerful tool for identifying tumors with a highly metastatic potential. With this study, we investigated the prognostic value of CINSARC signature on a cohort of 48 pediatric (PEDs) and AYAs-RMS.

RESULTS

CINSARC resulted not significantly correlated with age, suggesting other determinants to be responsible for that difference in survival. It remained a significant prognostic variable in both the groups of PEDs and AYAs. Also, genomic grade index signature was tested on the same cohort and showed very similar results with CINSARC.

CONCLUSIONS

Our study showed that CINSARC correlated with outcome in RMS patients and may be potentially considered a tool to predict outcome, and so stratify RMS patients.

Rationale of the rare cancer list: a consensus paper from the Joint Action on Rare Cancers (JARC) of the European Union (EU)

Background

The Surveillance of Rare Cancers in Europe (RARECARE) project proposed a definition and a list of rare cancers. The Joint Action on Rare Cancers (JARC), launched by the European Union and involving 18 member states and 34 partners, promoted a wide consensus effort to review the list.

Patients and methods

A group of experts was set up, including scientific societies, member state representatives of JARC, representatives of the European Reference Networks dedicated to rare cancers and rare cancer patient advocates. The definition and the list of rare clinical entities, based on the incidence data provided by two European projects (RARECARE and RARECAREnet), were rediscussed through a consensus meeting of the expert panel.

Results

By consensus, it was reiterated that the best criterion for a definition of rare cancers is incidence, rather than prevalence. By consensus, the experts slightly modified the composition of the tiers of rare cancers, according to the definition based on an incidence threshold <6/100 000/year, and grouped all rare cancers within 12 families of rare cancers. Even when defined conservatively this way, rare cancers are not rare collectively, since they correspond to 10%–20% of all cancer cases.

Conclusions

The list of rare cancers reviewed by JARC should be viewed as a tool in the fight against rare cancers and rare diseases. It may help to appreciate that rare cancers are cancers and rare diseases at the same time, combining issues and difficulties of both. We hope that refinements to the list and a wider understanding of its implications may contribute to increase awareness of problems posed by rare cancers and to improve quality of care in a large group of patients with cancer, who may be discriminated against just because of the low frequency of their diseases.

The Challenge of Melanocytic Lesions in Pediatric Patients: Clinical-Pathological Findings and the Diagnostic Value of PRAME

Pediatric melanoma is a rare disease especially in children aged younger than 10 years old. Recent estimates report a rise of disease incidence in both adults and children. Diagnostic work-up is challenging in pediatric melanoma, as it displays a wide range of clinical presentations. Immunohistochemical biomarkers have been reported as predictors of malignancy in melanoma, however data specific to pediatric melanoma are poor. Our study aims to contribute to provide evidence of pediatric melanoma clinical features and differential diagnosis in this patient population. We describe our experience with a retrospective case series of pigmented skin lesions including malignant melanoma, atypical spitzoid tumor, and benign nevi in children and adolescents aged less than 16 years. We described the clinical and demographic characteristics of the cohort and evaluated the immunohistochemical expression of the PReferentially expressed Antigen in MElanoma (PRAME) for differential diagnosis of melanoma in children. The series displayed a similar distribution of melanoma between males and females, and the most common site of melanoma onset were the upper and lower limbs. In our cohort, PRAME was negative in most cases. Focal and slight positivity (from 1 to 5% of the neoplastic cells) was observed in four cases (two Spitz nevi and two atypical Spitz tumors). A moderate positivity in 25% of the neoplastic cells was observed in one case of atypical Spitz tumor. Immunohistochemical expression of PRAME might be useful in the differential diagnosis of malignant melanoma.

The European Paediatric Rare Tumours Network - European Registry (PARTNER) project for very rare tumors in children

The PARTNER project (Paediatric Rare Tumours Network - European Registry) was launched in 2016. PARTNER aims to create a European Registry dedicated to children and adolescents with very rare tumors (VRT). It links existing national registries and provides a registry for those countries in which a VRT registry has not yet been created. This consortium is composed of the various national cooperative groups and their respective member institutions. The strategic value of this project is based on the Europe-wide data collection concerning the treatment of VRTs. These data are provided to experts and constitute the basis for new clinical practice guidelines for use by ERN (European Reference Network) and non-ERN institutions. The proposed tasks and milestones will increase collaboration in the field of pediatric oncology among member states and will also facilitate the inclusion of low health expenditure average rate (LHEAR) countries in this process. In addition, this project creates a platform for VRTs that may represent a model on how to elaborate a comprehensive approach (case registration, international case consultation and treatment recommendations, and website to provide information for parents/patients) for rare diseases.

Correlation between oncological family history and clinical outcome in a large monocentric cohort of pediatric patients with rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS), an aggressive soft tissue sarcoma of the skeletal muscle generally affecting children and adolescents, shows extensive heterogeneity in histology, site and age of onset, clinical course, and prognosis. Tumorigenesis of RMS is multifactorial and genetic predisposition together with the family history of cancer may provide critical information to enhance the current knowledge and foster genetic counseling and testing.

METHODS

In our study, we evaluated the possible correlation of oncological family history with clinical outcomes in a cohort of RMS 512 patients and treated at the Pediatric Oncology Unit of our Institute. Family history was retrospectively collected from the specific ad hoc form available in medical records and filled in through an interview with the patients' parents at the time of RMS diagnosis.

RESULTS

While our series did not show a specific association between oncological family history and clinical variables, we observed an association with survival probabilities: among patients with a history of cancer-affected first-degree relatives at the time of the diagnosis, all children with alveolar RMS (ARMS) died of disease.

CONCLUSION

Our study not only reports an interesting and not previously described association between a poor clinical outcome and ARMS in patients with young cancer-affected relatives, but also stimulates the discussion on oncological family history in RMS, to improve the clinical management of these young patients and their families.

Cutaneous melanoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations

Cutaneous melanoma is rare in children and, like other very rare pediatric tumors, it suffers from a shortage of knowledge and clinical expertise. The clinical management of pediatric melanoma is often challenging. Its clinical and pathological diagnosis may be difficult, and there is no standard treatment. In the absence of specific treatment guidelines, young patients are generally treated following the same principle as for adults, but concern remains about their access to clinical trials and new drugs, which have been shown to dramatically change the natural history of advanced melanoma. This paper presents the internationally recognized recommendations for the diagnosis and treatment of children and adolescents with cutaneous melanoma, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) within the EU-funded project called PARTNER (Paediatric Rare Tumours Network - European Registry). Main recommendations for melanoma are to discuss pediatric patients in multidisciplinary teams that include both pediatric oncologists and specialists in adult melanoma; to enroll patients in prospective trials, if available; to collect data in national-international databases; and to develop an effective international collaboration between pediatric and adult melanoma groups in order to facilitate the transfer of potentially effective new agents from the adult to the pediatric setting.

Facing the challenges of very rare tumors of pediatric age: The European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) background, goals, and achievements

It has become increasingly clear in recent years that we need to develop ad hoc strategies to combat very rare tumors (VRT) of pediatric age. In 2008, several schemes being run in different countries were pooled together to create the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) project: a cooperative study group that aimed to promote research in the relatively uncharted territory of rare tumors of pediatric age. EXPeRT members were able to activate different levels of cooperation to achieve their goals, and to obtain dedicated funding by participating in EU-financed projects. Their experiences emphasize the merits of networking, seeking new partnerships, joining forces, and pooling resources to extend the reach of research efforts, and ultimately improve the quality of patient care. Between 2018 and 2021, the EXPeRT has been active in establishing the Pediatric Rare Tumors Network - European Registry (PARTNER). This project had the main purposes of building a European common registry of pediatric VRT, but also the major task of developing diagnostic and treatment guidelines for VRT (or at least part of them). These clinical recommendations are the subject of a series of papers on Pediatric Blood and Cancer.

Rare tumors: Retinoblastoma, nasopharyngeal cancer, and adrenocorticoid tumors

The role of surgery, chemotherapy, and radiation therapy for retinoblastoma has evolved considerably over the years with the efficacy of intraarterial chemotherapy and the high incidence of secondary malignant neoplasms following radiation therapy. The use of spot scanning intensity-modulated proton therapy may reduce the risk of secondary malignancies. For pediatric nasopharyngeal carcinoma, the current standard of care is induction chemotherapy followed by chemoradiation therapy. For adrenocortical carcinoma, the mainstay of treatment is surgery and chemotherapy. The role of radiation therapy remains to be defined.

Ultra-rare cystic disease

Diffuse cystic lung diseases include a group of heterogeneous disorders characterised by the presence of cysts within the lung parenchyma, sometimes showing a characteristic computed tomography scan pattern that allows diagnosis. The pathogenetic mechanisms underlying cyst formation in the lung are still not clear and a number of hypotheses have been postulated according to the different aetiologies: ball-valve effect, ischaemic dilatation of small airways and alveoli related to infiltration and obstruction of small vessels and capillaries that supply the terminal bronchioles and connective tissue degradation by matrix metalloproteases. A wide number of lung cyst diseases have been classified into six diagnostic groups according to the aetiology: neoplastic, congenital/genetic, lymphoproliferative, infective, associated with interstitial lung diseases, and other causes. This article focuses on lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis and Erdheim–Chester disease, Birt–Hogg–Dubé, follicular bronchiolitis and lymphocytic interstitial pneumonia, light-chain deposition disease and amyloidosis, congenital lung disease associated with aberrant lung development and growth, and cystic lung disease associated with neoplastic lesion. These cystic diseases are epidemiologically considered as ultra-rare conditions as they affect fewer than one individual per 50 000 or fewer than 20 individuals per million. Despite the rarity of this group of disorders, the increasing use of high-resolution computed tomography has improved the diagnostic yield, even in asymptomatic patients allowing prompt and correct therapy and management without the need for a biopsy.

Diffuse cystic lung diseases show a characteristic CT scan pattern that often allows for diagnosis, even in asymptomatic patients, allowing prompt correct therapy and management without the needing of a biopsyhttps://bit.ly/2wIUKet

Impact of Rhabdomyosarcoma Treatment Modalities by Age in a Population-Based Setting

Purpose: Rhabdomyosarcoma (RMS) has a worse prognosis in adults than in children, but there is evidence of a better outcome in the former if treated using a pediatric-like approach. This study describes treatment for RMS in patients more than 10 years old and examines to what extent treatment contributes to explain the different age-related survival observed and to what extent treatment centers impact treatment appropriateness. Methods: A retrospective population-based study was developed considering 104 RMS cases (excluding the pleomorphic subtype) diagnosed in Italy between 2000 and 2015. Patients were grouped by age (10-19 vs. 20-60 years old) and scored according to whether or not their chemotherapy was consistent with the schemes used in pediatric protocols (score 1 = chemotherapy in line with pediatric protocols). Treatment centers were grouped according to whether or not they have a pediatric-dedicated unit affiliated to the national pediatric oncology network (Associazione Italiana Ematologia Oncologia Pediatrica [AIEOP]). Results: Older patients were more likely to have tumors at unfavorable sites (p = 0.045). A treatment score of 1 was assigned to 85% of younger patients, but only to 32% of older patients (p < 0.001). Furthermore, the proportion of score 1 was higher in younger patients treated in centers with an AIEOP Unit. A multivariate model confirmed age as a significant prognostic factor (Hazard rate ratio [HR] = 2.06; p = 0.04) and showed a significant impact of treatment on survival (HR = 2.13; p = 0.03). Conclusions: Adult RMS patients are still relatively unlikely to be treated with pediatric protocols and in centers with a pediatric oncology expertise. This may explain the survival gap between older and younger patients.

Inequalities in diagnosis and registration of pediatric very rare tumors: a European study on pleuropulmonary blastoma

Very rare tumors (VRTs) account for up to 11% of childhood cancers. Dedicated national groups and registries only exist in some European countries. Pleuropulmonary blastoma (PPB) is a very rare intrathoracic pediatric tumor with a potentially severe prognosis. Due to its rarity, it sometimes goes unrecognized. We investigated PPB diagnostic capability and possible correlations between diagnostic performance and VRT-dedicated activities. The number of cases of PPB registered between 2000 and 2014 at pediatric oncology centers in Europe was compared with the number of expected cases. Data sources included VRT registries, population-based cancer registries, and hospital registries. Data were obtained for 25 countries, grouped into 4 geographical regions. The expected cases were 111, and the observed cases were 129. The observed-to-expected ratio was 1.86 for Northern Europe, 1.33 for Southern Europe, 1.22 for Central Europe, and 0.65 for Eastern Europe. More cases than expected were registered in all countries with an official VRT registry.Conclusion: The number of cases observed is consistent with expectations, but disparities exist across Europe. Difficulties in diagnosing PPB emerged in most Eastern countries. The incidence rate of PPB may be underestimated. The creation of VRT-dedicated groups and a European Registry for VRTs could help to reduce inequalities.What is Known:• Very rare pediatric tumors are often not recognized, despite representing almost 11% of childhood cancers .• Pleuropulmonary blastoma is a rare pediatric tumor with a poor prognosis.What is New:• The ability to diagnose and register pleuropulmonary blastoma varies in Europe.Registries dedicated to very rare pediatric tumors improve the diagnostic rates.• The incidence rate of pleuropulmonary blastoma may currently be underestimated.

Challenges and solutions to the study of rare childhood tumors

PURPOSE OF REVIEW

The majority of progress made in pediatric oncology over the past 50 years has been achieved in the most common cancers. Rare pediatric cancers, which collectively comprise more than 10% of all pediatric cancers, pose multiple challenges to researchers and clinicians, all which stem from the infrequency of these cancers. There has been a tremendous increase in focus on rare pediatric cancers by international consortia and registries, disease-specific clinics, and divisions of academic children's hospitals in the last 10 years. This focus, along with the progress made in cancer genomics, has changed the landscape for the study and treatment of rare pediatric cancers. This review focuses on the past, present, and future of the study and treatment of rare pediatric cancers.

RECENT FINDINGS

Cancer genomics is changing the way some cancers are being diagnosed, categorized, and treated. Rare pediatric cancers potentially stand to greatly benefit from advances in precision diagnosis and treatment.

SUMMARY

The challenges of studying rare pediatric cancers are well known. By utilizing similar techniques that allowed for progress in the common pediatric malignancies, namely collaboration, increased focus, greater funding, and utilization of cancer genomics, progress in the study and treatment of rare pediatric cancers is promising.

Exploring heterogeneity of adrenal cortical tumors in children: The French pediatric rare tumor group (Fracture) experience

INTRODUCTION

Pediatric adrenal cortical tumors are characterized by a wide spectrum of behavior. Questions remain regarding intermediate disease stages with isolated tumor rupture or relapse.

OBJECTIVES

To describe clinical characteristics, treatment strategy, and outcome of patients depending on disease stage, tumor rupture, or in case of a refractory tumor, to discuss optimal management.

MATERIAL AND METHODS

Pediatric patients with histological material reviewed and treated between 2000 and 2018 in 23 French oncology centers were included.

RESULTS

Among 95 cases, 59% of patients had stage I tumors (n = 55), 16% had stage II tumors (n = 16), 19% had stage III tumors (n = 17), and 5% had stage IV tumors (n = 5) (missing data: 2). Overall, 27% of patients (n = 25) had an unfavorable histology. Initial tumor resection was performed for 90% of patients (n = 86). Systemic therapies included mitotane in 20 cases and chemotherapy in 13 cases. Among 17 stage III patients, 12 had microscopic residual tumor due to an initial biopsy (n = 5), intraoperative rupture (n = 8), or surgical resection with microscopic residue or tumor spillage surgery (n = 1) (two patients with two modalities). After a median follow-up of 96 months (25-119), four early progressions and two relapses occurred. A total of seven patients died, including five of disease. Stage III diseases due to microscopic residual disease correlated with a worse prognosis: 5-year progression-free survival 44% (95% CI, 22-87%) versus 82% (95% CI, 73-91%) for the whole cohort (P < .0001). Among the 14 patients with refractory disease, only 3 were alive and free of disease after multimodal second-line therapy.

CONCLUSIONS

Stage III diseases due to a microscopic residual tumor have a dismal prognosis, arguing for the systematic use of adjuvant therapy. Patients with a relapsed disease should be included in experimental studies.

Differential diagnosis of solid pancreatic masses

Solid pancreatic lesions include mainly adenocarcinoma, neuroendocrine tumors pancreatic cystic neoplasms with solid component, solid pseudopapillary tumor, pancreatoblastoma, pancreatic lymphoma, and pancreatic metastasis. The most frequent pancreatic lesion is the adenocarcinoma, representing between 70% and 95% of all solid pancreatic neoplasm. The diagnosis of these lesions can be a challenge and currently, there are different imaging techniques such as CT scan, EUS and MRI with high sensitivity and specificity. The most widely used technique for the initial evaluation is the CT scan with a sensitivity between 76% and 92% for the diagnosis of pancreatic cancer. The EUS has a sensitivity for the detection of pancreatic lesions of around 98% and is accepted to be the most sensitive technique for the detection of small pancreatic tumors (<2 cm). The MRI, with a very high soft-tissue contrast resolution, provides an accuracy in the detection and staging of adenocarcinoma of 90-100%. A multimodality approach is usually necessary in patients with clinical suspicion of pancreatic lesion. The EUS is required for the local evaluation of the relation of the lesion with vessels and for tissue acquisition and the CT scan and/or MRI is usually required for the local and distance staging in case of pancreatic cancer. The purpose of this review is to provide an overview of solid pancreatic lesions and the role of the different imaging techniques in their evaluation.

Vinorelbine and continuous low-dose cyclophosphamide as maintenance chemotherapy in patients with high-risk rhabdomyosarcoma (RMS 2005): a multicentre, open-label, randomised, phase 3 trial

BACKGROUND

For more than three decades, standard treatment for rhabdomyosarcoma in Europe has included 6 months of chemotherapy. The European paediatric Soft tissue sarcoma Study Group (EpSSG) aimed to investigate whether prolonging treatment with maintenance chemotherapy would improve survival in patients with high-risk rhabdomyosarcoma.

METHODS

RMS 2005 was a multicentre, open-label, randomised, controlled, phase 3 trial done at 102 hospitals in 14 countries. We included patients aged 6 months to 21 years with rhabdomyosarcoma who were considered to be at high risk of relapse: those with non-metastatic incompletely resected embryonal rhabdomyosarcoma occurring at unfavourable sites with unfavourable age (≥10 years) or tumour size (>5 cm), or both; those with any non-metastatic rhabdomyosarcoma with nodal involvement; and those with non-metastatic alveolar rhabdomyosarcoma but without nodal involvement. Patients in remission after standard treatment (nine cycles of ifosfamide, vincristine, dactinomycin with or without doxorubicin, and surgery or radiotherapy, or both) were randomly assigned (1:1) to stop treatment or continue maintenance chemotherapy (six cycles of intravenous vinorelbine 25 mg/m2 on days 1, 8, and 15, and daily oral cyclophosphamide 25 mg/m2, on days 1-28). Randomisation was done by use of a web-based system and was stratified (block size of four) by enrolling country and risk subgroup. Neither investigators nor patients were masked to treatment allocation. The primary outcome was disease-free survival in the intention-to-treat population. Secondary outcomes were overall survival and toxicity. This trial is registered with EudraCT, number 2005-000217-35, and ClinicalTrials.gov, number NCT00339118, and follow-up is ongoing.

FINDINGS

Between April 20, 2006, and Dec 21, 2016, 371 patients were enrolled and randomly assigned to the two groups: 186 to stop treatment and 185 to receive maintenance chemotherapy. Median follow-up was 60·3 months (IQR 32·4-89·4). In the intention-to-treat population, 5-year disease-free survival was 77·6% (95% CI 70·6-83·2) with maintenance chemotherapy versus 69·8% (62·2-76·2) without maintenance chemotherapy (hazard ratio [HR] 0·68 [95% CI 0·45-1·02]; p=0·061), and 5-year overall survival was 86·5% (95% CI 80·2-90·9) with maintenance chemotherapy versus 73·7% (65·8-80·1) without (HR 0·52 [95% CI 0·32-0·86]; p=0·0097). Toxicity was manageable in patients who received maintenance chemotherapy: 136 (75%) of 181 patients had grade 3-4 leucopenia, 148 (82%) had grade 3-4 neutropenia, 19 (10%) had anaemia, two (1%) had thrombocytopenia, and 56 (31%) had an infection. One (1%) patient had a grade 4 non-haematological toxicity (neurotoxicity). Two treatment-related serious adverse events occurred: one case of inappropriate antidiuretic hormone secretion and one of a severe steppage gait with limb pain, both of which resolved.

INTERPRETATION

Adding maintenance chemotherapy seems to improve survival for patients with high-risk rhabdomyosarcoma. This approach will be the new standard of care for patients with high-risk rhabdomyosarcoma in future EpSSG trials.

FUNDING

Fondazione Città della Speranza, Association Léon Berard Enfant Cancéreux, Clinical Research Hospital Program (French Ministry of Health), and Cancer Research UK.