Clinical and biological landscape of constitutional mismatch-repair deficiency syndrome: an International Replication Repair Deficiency Consortium cohort study

BACKGROUND

Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare and aggressive cancer predisposition syndrome. Because a scarcity of data on this condition contributes to management challenges and poor outcomes, we aimed to describe the clinical spectrum, cancer biology, and impact of genetics on patient survival in CMMRD.

METHODS

In this cohort study, we collected cross-sectional and longitudinal data on all patients with CMMRD, with no age limits, registered with the International Replication Repair Deficiency Consortium (IRRDC) across more than 50 countries. Clinical data were extracted from the IRRDC database, medical records, and physician-completed case record forms. The primary objective was to describe the clinical features, cancer spectrum, and biology of the condition. Secondary objectives included estimations of cancer incidence and of the impact of the specific mismatch-repair gene and genotype on cancer onset and survival, including after cancer surveillance and immunotherapy interventions.

FINDINGS

We analysed data from 201 patients (103 males, 98 females) enrolled between June 5, 2007 and Sept 9, 2022. Median age at diagnosis of CMMRD or a related cancer was 8·9 years (IQR 5·9-12·6), and median follow-up from diagnosis was 7·2 years (3·6-14·8). Endogamy among minorities and closed communities contributed to high homozygosity within countries with low consanguinity. Frequent dermatological manifestations (117 [93%] of 126 patients with complete data) led to a clinical overlap with neurofibromatosis type 1 (35 [28%] of 126). 339 cancers were reported in 194 (97%) of 201 patients. The cumulative cancer incidence by age 18 years was 90% (95% CI 80-99). Median time between cancer diagnoses for patients with more than one cancer was 1·9 years (IQR 0·8-3·9). Neoplasms developed in 15 organs and included early-onset adult cancers. CNS tumours were the most frequent (173 [51%] cancers), followed by gastrointestinal (75 [22%]), haematological (61 [18%]), and other cancer types (30 [9%]). Patients with CNS tumours had the poorest overall survival rates (39% [95% CI 30-52] at 10 years from diagnosis; log-rank p<0·0001 across four cancer types), followed by those with haematological cancers (67% [55-82]), gastrointestinal cancers (89% [81-97]), and other solid tumours (96% [88-100]). All cancers showed high mutation and microsatellite indel burdens, and pathognomonic mutational signatures. MLH1 or MSH2 variants caused earlier cancer onset than PMS2 or MSH6 variants, and inferior survival (overall survival at age 15 years 63% [95% CI 55-73] for PMS2, 49% [35-68] for MSH6, 19% [6-66] for MLH1, and 0% for MSH2; p<0·0001). Frameshift or truncating variants within the same gene caused earlier cancers and inferior outcomes compared with missense variants (p<0·0001). The greater deleterious effects of MLH1 and MSH2 variants as compared with PMS2 and MSH6 variants persisted despite overall improvements in survival after surveillance or immune checkpoint inhibitor interventions.

INTERPRETATION

The very high cancer burden and unique genomic landscape of CMMRD highlight the benefit of comprehensive assays in timely diagnosis and precision approaches toward surveillance and immunotherapy. These data will guide the clinical management of children and patients who survive into adulthood with CMMRD.

FUNDING

The Canadian Institutes for Health Research, Stand Up to Cancer, Children's Oncology Group National Cancer Institute Community Oncology Research Program, Canadian Cancer Society, Brain Canada, The V Foundation for Cancer Research, BioCanRx, Harry and Agnieszka Hall, Meagan's Walk, BRAINchild Canada, The LivWise Foundation, St Baldrick Foundation, Hold'em for Life, and Garron Family Cancer Center.

Retinoblastoma in Asia: Clinical Presentation and Treatment Outcomes in 2112 Patients from 33 Countries

PURPOSE

To describe the clinical presentation and treatment outcomes of children who received a diagnosis of retinoblastoma in 2017 throughout Asia.

DESIGN

Multinational, prospective study including treatment-naïve patients in Asia who received a diagnosis of retinoblastoma in 2017 and were followed up thereafter.

PARTICIPANTS

A total of 2112 patients (2797 eyes) from 96 retinoblastoma treatment centers in 33 Asian countries.

INTERVENTIONS

Chemotherapy, radiotherapy, enucleation, and orbital exenteration.

MAIN OUTCOME MEASURES

Enucleation and death.

RESULTS

Within the cohort, 1021 patients (48%) were from South Asia (SA), 503 patients (24%) were from East Asia (EA), 310 patients (15%) were from Southeast Asia (SEA), 218 patients (10%) were from West Asia (WA), and 60 patients (3%) were from Central Asia (CA). Mean age at presentation was 27 months (median, 23 months; range, < 1-261 months). The cohort included 1195 male patients (57%) and 917 female patients (43%). The most common presenting symptoms were leukocoria (72%) and strabismus (13%). Using the American Joint Committee on Cancer Staging Manual, Eighth Edition, classification, tumors were staged as cT1 (n = 441 [16%]), cT2 (n = 951 [34%]), cT3 (n = 1136 [41%]), cT4 (n = 267 [10%]), N1 (n = 48 [2%]), and M1 (n = 129 [6%]) at presentation. Retinoblastoma was treated with intravenous chemotherapy in 1450 eyes (52%) and 857 eyes (31%) underwent primary enucleation. Three-year Kaplan-Meier estimates for enucleation and death were 33% and 13% for CA, 18% and 4% for EA, 27% and 15% for SA, 32% and 22% for SEA, and 20% and 11% for WA (P < 0.0001 and P < 0.0001), respectively.

CONCLUSIONS

At the conclusion of this study, significant heterogeneity was found in treatment outcomes of retinoblastoma among the regions of Asia. East Asia displayed better outcomes with higher rates of globe and life salvage, whereas Southeast Asia showed poorer outcomes compared with the rest of Asia.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The role of International Society of Paediatric Oncology (SIOP) in advancing global childhood cancer care

The Société Internationale d'Oncologie Pédiatrique [International Society of Paediatric Oncology] (SIOP), founded in 1969, aims to improve the lives of children and adolescents with cancer through global collaboration, education, training, research and advocacy. The annual congress provides the opportunity to share late-breaking research, clinical experiences and debate, with experts worldwide. SIOP's six Continental Branches represent their constituent members in North America, Oceania, Latin America, Africa, Europe and Asia and bring best practices and recent research findings of value to their specific patient populations. In 1990, the SIOP Board of Directors addressed the formerly predominantly European/North American society transforming into a global association by establishing a scholarship program to bring low- and middle-income country (LMIC) paediatric oncologists and nurses to SIOP meetings. A major achievement was SIOP's acceptance as a World Health Organisation (WHO) non-state actor in official relations in 2018, joining 220 non-governmental organisations, international business associations and philanthropic foundations with this privilege. SIOP supports advocacy with WHO member states and civil society to highlight the specific needs of cancer in this age-group through key programs especially supporting the WHO Global Initiative for Childhood Cancer. Sustained improvement in childhood cancer outcomes has paralleled the integration of research with care; thus, SIOP launched a Programme for Advancing Research Capacity for funding selected clinical trial groups in LMICs. SIOP supports south-south partnerships, and the principles elegantly expressed in SIOP Africa's checklist for co-branding projects, that include the prioritisation of local needs, cultivation of local expertise and commitment to equitable partnerships. SIOP now counts approximately 3,000 members from over 128 countries; 39% are from more than 60 LMICs. SIOP members have multidisciplinary expertise on all aspects of childhood cancer care working in collaboration with key stakeholders including governments, civil society organisations and funders to improve the lives of children/adolescents with cancer everywhere in all ways.

Taboo words in pediatric oncology: Communication experiences of nurses and physicians with dying children and their families

PURPOSE

Despite the numerous benefits of effective communication between patients, families, and healthcare professionals, there are still substantial barriers and communication challenges. This study investigated the experiences of nurses and doctors working in different pediatric hematology-oncology units in Turkey communicating with children and their parents about end-of-life issues.

METHOD

This qualitative study was conducted with twenty-four physicians and nurses. A descriptive phenomenological approach was used. Data were analyzed using Braun and Clarke's six-step reflexive thematic analysis. The MAXQDA software was used to facilitate data management.

RESULTS

The findings revealed three main themes describing end-of-life communication experiences of physicians and nurses: Avoiding communication with a dying child, Everyone knows but nobody talks, and Complicating aspects of the setting.

CONCLUSIONS

Communication with dying children and their families is essential. However, multiple barriers remain for healthcare providers to do so. That issue burdens the child and their family more during the end-of-life, which is already a challenging experience to handle. Healthcare professionals need urgent training in communication with the dying children and their families.

Investigation of the methylation changes in the promoter region of RB1 gene in retinoblastoma: Unraveling the epigenetic puzzle in retinoblastoma

Retinoblastoma is an infrequent neoplasm that arises during childhood from retinal nerve cells and is attributed to the biallelic inactivation of the RB1 gene. In conjunction with anatomical anomalies, it is widely acknowledged that epigenetic modifications play a significant role in the pathogenesis of cancer. The association between methylation of the RB1 gene promoter and tumor formation has been established; however, there is currently no scholarly evidence to substantiate the claim that it is responsible for the inheritance of retinoblastoma. The initial hypothesis posited for this work was that familial retinoblastoma disease would be similarly observed in cases with RB1 promotor gene methylation, akin to RB1 mutations. The RB1 gene promoter region was subjected to methylation screening using real-time PCR in individuals diagnosed with familial retinoblastoma but lacking RB1 mutations. The study involved a comparison of the germline methylation status of the RB1 gene in the peripheral blood samples of 50 retinoblastoma patients and 52 healthy individuals. The healthy individuals were carefully selected to match the retinoblastoma patients in terms of age, sex, and ethnicity. The data obtained from both groups were subjected to statistical analysis. The study revealed that the methylation level in a cohort of 50 individuals diagnosed with retinoblastoma and 52 healthy control participants was determined to be 36.1% and 33.9%, respectively. As a result, there was no statistically significant disparity observed in RB1 promoter methylation between the patient and control groups (p = 0.126). The methylation of the promoter region of the RB1 gene in familial retinoblastoma does not exert any influence on the hereditary transmission of the disease.

18 F-FDG-PET/CT imaging in diagnostic workup of pediatric precursor B-cell lymphoblastic lymphoma

18 F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) imaging is currently not used in standard diagnostics for B-cell precursor lymphoblastic lymphoma (BCP-LBL), and it is unknown whether PET/CT imaging would lead to agreement between detection of lesions with the gold standard imaging methods. Therefore, we performed a retrospective cohort study in which we included 32 pediatric BCP-LBL patients and determined localizations by reviewing local imaging reports. There was a disagreement between protocol-based imaging and PET/CT in 59% of the patients, and the discrepancies mostly comprise of additional lesions detected with PET/CT, typically in lymph node and bone or the absence of bone marrow involvement with PET/CT. If PET/CT was leading in determining definite stage of disease, this would lead to a different stage and therapy branch in 31% and 28% of the patients, respectively.

Late Relapse in Neuroblastoma: Case Report and Review of the Literature

BACKGROUND

Neuroblastoma is the most common extra-cranial solid tumor in children. The survival rate of relapsed/refractory neuroblastoma is dismal. Late recurrence may occur rarely.

CASE PRESENTATION

We have, herein, presented a case with stage IV neuroblastoma who relapsed after 11 years and had a subsequent relapse after 15 years from the initial diagnosis, and reviewed cases with late relapsed (after >5 years) neuroblastoma in the literature. The case presented with recurrent disease at the T7 vertebra after 11 years from the initial diagnosis. The patient received surgery, chemotherapy, MIBG treatment, and antiGD2 combined with chemotherapy, and had a further local recurrence in the paravertebral area of the removed T7 vertebra after three years. The patient was operated, received anti-GD2 combined with chemotherapy, and is still alive with no symptoms for 19 months after the last relapse.

CONCLUSION

There is not a well-established treatment regimen for the majority of these patients. MIBG treatment and antiGD2 combined with chemotherapy may be promising options for relapsed/ refractory neuroblastoma.

RB1 gene mutations and genetic spectrum in retinoblastoma cases

The aim of the study was to investigate the frequency and types of mutations on the retinoblastoma gene (RB1 gene) in Turkish population. RB1 gene mutation analysis was performed in a total of 219 individuals (122 probands with retinoblastoma, 14 family members with retinoblastoma and 83 clinically healthy family members). All 27 exons and close intronic regions of the RB1 gene were sequenced for small deletions and insertions using both the Sanger sequencing or NGS methods, and the large deletions and duplications were investigated using the MLPA analysis and CNV algorithm. The bilateral/trilateral retinoblastoma rate was 66% in the study population. The general frequency of RB1 gene mutation in the germline of the patients with retinoblastoma was 41.9%. Approximately 51.5% of the patients were diagnosed earlier than 12 months old, and de novo mutation was found in 32.4% of the patients. Germline small genetic rearrangement mutations were detected in 78.9% of patients and LGRs were detected in 21.1% of patients. An association was detected between the eye color of the RB patients and RB1 mutations. 8 of the mutations detected in the RB1 gene were novel in the study.

Comparison of Heparin and Saline for Prevention of Central Venous Catheter Occlusion in Pediatric Oncology: A Systematic Review and Meta-Analysis

OBJECTIVE

The management of central venous catheter (CVC) occlusion remains an area without clear evidence-based guidelines. Studies have been conducted that compare the use of heparin and normal saline for reducing thrombosis, but the evidence is not strong enough to suggest a significant advantage of one over the other. Therefore, the study aimed to assess the effectiveness of heparin and normal saline flushing in preventing CVC occlusion in pediatric patients with cancer.

DATA SOURCES

A comprehensive search was conducted in PubMed, Web of Science, Cochrane, MEDLINE, CINAHL, Embase, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov platform using specific keywords. The search was conducted until March 2022. Five randomized controlled trials are included in this study.

CONCLUSION

Five studies with a total of 316 pediatric cancer patients met the inclusion criteria. The studies were found to be heterogeneous due to variations in the types of cancer, heparin concentration, flushing frequency of CVCs, and methods used to measure occlusion. Despite these differences, there was no significant difference in the effect of flushing with heparin and normal saline in preventing CVC occlusion. The analysis revealed that normal saline is as effective as heparin in preventing CVC occlusion among pediatric cancer patients.

IMPLICATIONS FOR NURSING PRACTICE

This systematic review and meta-analysis demonstrated that there is no significant difference between the use of heparin and normal saline flushing in preventing CVC occlusion among pediatric cancer patients. Considering the potential risks of heparin, the use of normal saline flushing may be recommended to prevent CVC obstruction.

A rare cause of intestinal obstruction in children: signet-ring cell adenocarcinoma of the colon

BACKGROUND

Signet-ring cell adenocarcinoma of the colon is well-recognized in adult patients who are extremely rare and not well-documented in children. Our study aims to raise awareness about this rare disease and its long-term outcomes.

METHODS

We retrospectively evaluated patients with signet-ring cell colon adenocarcinoma.

RESULTS

Six patients, three boys and three girls, with a mean age of 14.83 (range, 13-17 years), presented with signs of intesti-nal obstruction and were diagnosed with signet-ring cell colon adenocarcinoma. All patients had air-fluid levels on abdominal X-ray. Abdominal ultrasonography of all patients revealed subileus. Abdominal computed tomography was performed in five patients, and pre-operative colonoscopy was conducted in two patients before the emergency intervention. All of the patients underwent emergent exploratory laparotomy with the preliminary diagnosis of acute abdomen. In two patients, debulking surgery followed by a stoma was performed. The remaining four patients were treated with anastomosis following intestinal resection. All girls had metastases on the ovary. One of the patients died due to the burden of multiple metastases in the early period, and three died in the sixth post-operative year. We have been following the remaining two patients since then.

CONCLUSION

Although signet-ring cell carcinomas (SRCCs) are rare, they should be considered in the differential diagnosis of acute abdomen and intestinal obstruction in pediatric patients. Despite early diagnosis and treatment, SRCC has a poor prognosis in the pediatric population.

Long-Term Endocrinologic Follow-Up of Children with Brain Tumors and Comparison of Growth Hormone Therapy Outcomes: A SingleCenter Experience

OBJECTIVE

Brain tumors in childhood carry a high risk for endocrine disorders due to the direct effects of the tumor and/or surgery and radiotherapy. Somatotropes are vulnerable to pressure and radiotherapy; therefore, growth hormone deficiency is one of the most frequent abnormalities. This study aimed to evaluate endocrine disorders and recombinant growth hormone treatment outcomes in brain tumor survivors.

MATERIALS AND METHODS

In this study, 65 (27 female) patients were classified into 3 groups as craniopharyngioma (n = 29), medulloblastoma (n = 17), and others (n = 19). "Others" group included astrocytoma, ependymoma, germinoma, pineoblastoma, and meningioma patients. Anthropometric data and endocrine parameters of patients and their growth outcome with/without recombinant growth hormone therapy were collected from medical records, retrospectively.

RESULTS

Mean age at the first endocrinological evaluation was 8.7 ± 3.6 years (range: 1.0- 17.1 years). Height, weight, and body mass index standard deviation score, mean ± standard deviation (median) values were -1.7 ± 1.7 (-1.5), -0.8 ± 1.9 (-0.8), and 0.2 ± 1.5 (0.4), respectively. Hypothyroidism (central 86.9%, primary 13.1%) was detected during follow-up in 81.5% of patients. Primary hypothyroidism in medulloblastoma (29.4%) was significantly higher compared to other groups (P = .002). The frequency of hypogonadotropic hypogonadism, central adrenal insufficiency, and diabetes insipidus was significantly high in the craniopharyngioma cases.

CONCLUSION

In our study, endocrine disorders other than growth hormone deficiency were also frequently observed. In craniopharyngioma cases, the response to recombinant growth hormone therapy was satisfactory. However, there was no improvement in height prognosis during recombinant growth hormone therapy in medulloblastoma patients. A multidisciplinary approach to the care of these patients, referral for endocrine complications, and guidelines on when recombinant growth hormone therapy is required.

Tandem high-dose chemotherapy followed by autologous stem cell transplantation: An infant with trilateral retinoblastoma

BACKGROUND

Retinoblastoma (RB) is the most common intraocular malignancy in childhood. Advanced RB, associated with exceedingly poor prognosis, requires more intensive multiagent chemotherapy than conventional regimens. Rescue of the bone marrow after intensive chemotherapy is achieved with stem cell transplantation. The sequential courses (tandem transplantation) of high-dose chemotherapy followed by autologous stem cell transplantation allow for even greater dose intensity in consolidation with the potential to use different active chemotherapeutics at each transplant and have proven feasible and successful in treating children with recurrent/refractory solid tumors.

CASE DESCRIPTION

We report an infant with trilateral high-risk RB who received tandem high-dose chemotherapy (HDC) followed by autologous stem cell transplantation after the conventional chemotherapy. A 5-month-old female patient presented with strabismus, and the ophthalmoscopic examination showed intraocular tumoral lesions in both eyes. Magnetic resonance imaging (MRI) concluded the trilateral retinoblastoma diagnosis due to a tumoral mass in the optic chiasm. The follow-up ophthalmologic examinations and the MRI detected stable disease after six cycles of multiagent chemotherapy.

CONCLUSIONS

Rescue with autologous stem cell transplantation after HDC allows for an increase in chemotherapy intensity. Tandem transplantation provides the chance to perform different chemotherapeutics at each transplant and enables an increase in the chemotherapy intensity, thus providing a positive effect on disease-free survival.

Central Nervous System Fungal Infections in Children With Leukemia and Undergoing Hematopoietic Stem Cell Transplantation: A Retrospective Multicenter Study

BACKGROUND

Central nervous system fungal infections (CNSFI) are seen in patients with hematologic malignancies and have high morbidity and mortality. Because of their rarity, there is limited data on CNSFI in children with no established treatment protocols or guidelines.

MATERIALS AND METHODS

In this multicenter retrospective study, 51 pediatric patients with leukemia, 6 of whom had undergone bone marrow transplantation, with proven or probable CNSFI were evaluated. Fungal infections were defined as proven or probable based on European Organisation for Research and Treatment of Cancer criteria. Proven CNSFI was diagnosed by appropriate central nervous system (CNS) imaging or tissue sample findings in combination with positive microbiological results of cerebrospinal fluid. A positive culture, microscopic evidence of hyphae, a positive result of the galactomannan assays are defined as positive microbiological evidence. Probable CNSFI was defined as appropriate CNS imaging findings together with proven or probable invasive fungal infections at another focus without CNS when there is no other explanatory condition. Data was collected by using the questionnaire form (Supplemental Digital Content 1, http://links.lww.com/JPHO/A541 ).

RESULTS

Seventeen patients had proven, 34 patients had probable CNSFI. Headaches and seizures were the most common clinical findings. The median time between the onset of fever and diagnosis was 5 days. The most common fungal agent identified was Aspergillus . Sixteen patients received single-agent, 35 received combination antifungal therapy. Surgery was performed in 23 patients. Twenty-two patients (43%) died, 29 of the CNSFI episodes recovered with a 20% neurological sequelae.

CONCLUSION

CNSFIs should be considered in the differential diagnosis in patients with leukemia and refractory/recurrent fever, headache, neurologicalocular symptoms, and a radiologic-serological evaluation should be performed immediately. Early diagnosis and prompt management, both medical and surgical, are essential for improving clinical outcomes.

Desires vs. conditions: A qualitative study exploring the factors affecting the place of death of child with cancer in Turkey

OBJECTIVE

The purpose of this study was to describe factors affecting the place of death of children with cancer at the end of life.

METHODS

The descriptive phenomenological approach was used. Eighteen mothers who lost their children to cancer participated in in-depth interviews. Data were analysed using MAXQDA software version. Codes and categories were developed inductively from participants' narratives.

RESULTS

The factors affecting the place of death of children were categorised into two main themes: (1) desires and (2) conditions. Most of the mothers reported that their deceased children wanted to be with their families at the end of life and they wanted to go home. The conditions related to health services were defined as the barriers to the death of their children in the places of death preferred by the mothers.

CONCLUSION

The desire to be close to the child was the main factor affecting the parents' decisions. The findings revealed the prevailing circumstances in the death place decision beyond parental desires. These were the child's health conditions, physical conditions of hospitals, and the lack of home care and paediatric palliative care services, which were factors related to the system, and the lack of other options for parents.

Pediatric Precursor B-Cell Lymphoblastic Malignancies: From Extramedullary to Medullary Involvement

B-cell lymphoblastic lymphoma (BCP-LBL) and B-cell acute lymphoblastic leukemia (BCP-ALL) are the malignant counterparts of immature B-cells. BCP-ALL is the most common hematological malignancy in childhood, while BCP-LBL accounts for only 1% of all hematological malignancies in children. Therefore, BCP-ALL has been well studied and treatment protocols have changed over the last decades, whereas treatment for BCP-LBL has stayed roughly the same. Clinical characteristics of 364 pediatric patients with precursor B-cell malignancies were studied, consisting of BCP-LBL (n = 210) and BCP-ALL (n = 154) patients. Our results indicate that based on the clinical presentation of disease, B-cell malignancies probably represent a spectrum ranging from complete isolated medullary disease to apparent complete extramedullary disease. Hepatosplenomegaly and peripheral blood involvement are the most important discriminators, as both seen in 80% and 95% of the BCP-ALL patients and in 2% of the BCP-LBL patients, respectively. In addition, we show that the overall survival rates in this cohort differ significantly between BCP-LBL and BCP-ALL patients aged 1−18 years (p = 0.0080), and that the outcome for infants (0−1 years) with BCP-LBL is significantly decreased compared to BCP-LBL patients of all other pediatric ages (p < 0.0001).

The Global Retinoblastoma Outcome Study: a prospective, cluster-based analysis of 4064 patients from 149 countries

Background

Retinoblastoma is the most common intraocular cancer worldwide. There is some evidence to suggest that major differences exist in treatment outcomes for children with retinoblastoma from different regions, but these differences have not been assessed on a global scale. We aimed to report 3-year outcomes for children with retinoblastoma globally and to investigate factors associated with survival.

Methods

We did a prospective cluster-based analysis of treatment-naive patients with retinoblastoma who were diagnosed between Jan 1, 2017, and Dec 31, 2017, then treated and followed up for 3 years. Patients were recruited from 260 specialised treatment centres worldwide. Data were obtained from participating centres on primary and additional treatments, duration of follow-up, metastasis, eye globe salvage, and survival outcome. We analysed time to death and time to enucleation with Cox regression models.

Findings

The cohort included 4064 children from 149 countries. The median age at diagnosis was 23·2 months (IQR 11·0–36·5). Extraocular tumour spread (cT4 of the cTNMH classification) at diagnosis was reported in five (0·8%) of 636 children from high-income countries, 55 (5·4%) of 1027 children from upper-middle-income countries, 342 (19·7%) of 1738 children from lower-middle-income countries, and 196 (42·9%) of 457 children from low-income countries. Enucleation surgery was available for all children and intravenous chemotherapy was available for 4014 (98·8%) of 4064 children. The 3-year survival rate was 99·5% (95% CI 98·8–100·0) for children from high-income countries, 91·2% (89·5–93·0) for children from upper-middle-income countries, 80·3% (78·3–82·3) for children from lower-middle-income countries, and 57·3% (52·1-63·0) for children from low-income countries. On analysis, independent factors for worse survival were residence in low-income countries compared to high-income countries (hazard ratio 16·67; 95% CI 4·76–50·00), cT4 advanced tumour compared to cT1 (8·98; 4·44–18·18), and older age at diagnosis in children up to 3 years (1·38 per year; 1·23–1·56). For children aged 3–7 years, the mortality risk decreased slightly (p=0·0104 for the change in slope).

Interpretation

This study, estimated to include approximately half of all new retinoblastoma cases worldwide in 2017, shows profound inequity in survival of children depending on the national income level of their country of residence. In high-income countries, death from retinoblastoma is rare, whereas in low-income countries estimated 3-year survival is just over 50%. Although essential treatments are available in nearly all countries, early diagnosis and treatment in low-income countries are key to improving survival outcomes.

Funding

Queen Elizabeth Diamond Jubilee Trust.

HGG-49. Gliomatosis cerebri in children: A collaborative report from the European Society for Pediatric Oncology (SIOPE)

BACKGROUND: Gliomatosis cerebri (GC), a radiologically defined diffusely infiltrating glioma, is no longer considered a distinct entity since the 2016 WHO classification for tumors of the CNS. Due to its rarity and dismal prognosis treatment recommendations in children remain ambiguous. Using central neuroradiological review, we performed a multi-institutional, retrospective study of GC providing comprehensive radiological, clinical, and (epi)genetic characterization. RESULTS: We included 104 patients between 1-19 years. Within a median follow-up of 15.5 months (range, 2.3-138.8), 93 patients (89.4 %) had died, 4 (3.8 %) were lost to follow-up and 7 (6.8 %) were alive with stable/progressive disease. Median progression-free- (PFS) and overall survival (OS) were 8.6 months (interquartile range, 4.3-14.0) and 15.5 months (10.9-27.7), respectively. Former WHO grading correlated significantly with median OS: WHO °II: 47.8 months (25.2-55.7); WHO °III: 15.9 months (11.4-26.3); WHO °IV: 10.4 months (8.8-14.4) (p&lt;0.001). In high-grade gliomas (HGG), radiochemotherapy showed best PFS (p=0.002). Compared to hemispheric pediatric non-GC HGG, GC phenotype was associated with decreased OS (p=0.001). Methylation-based classification and exome sequencing were possible for 49 and 45 patients, respectively. According to the 2021 WHO classification, most cases were considered as IDH-/H3-wildtype gliomas (n=37/49, 75.5 %), mostly with a pedRTK2 subtype (n=15, 30.6%), followed by pedMYCN (n=5, 10.2 %). Within the IDH-/H3-wildtype gliomas, EGFR-altered tumors (n=10) seemed overrepresented. Survival analyses revealed a better OS for IDH1-mutant tumors (n=6; 54.6 vs. 15.2 months in IDH-wildtype; p=0.015) and a worse OS for TP53-mutant tumors (n=6; p=0.001). Despite the potential overrepresentation of EGFR-altered tumors, no other specific molecular markers for GC could be identified so far. Further analyses are ongoing. CONCLUSIONS: GC in children is confirmed as a poor prognostic phenotype include various epigenetic pediatric glioma subtypes, without a proven (epi)genetic mark of its own. The relevance of overrepresented EGFR alterations has to be determined yet.

RB1 gene mutations in Turkish retinoblastoma patients

e22007

Background: Retinoblastoma (RB) is the most common intraocular malignancy in children, caused by mutations in the tumor suppressor RB1 gene. Patients with bilateral/trilateral/familial RB are considered to have hereditary RB (1 germline, 1 somatic mutation); although most unilateral RB are nonhereditary (2 somatic mutations), some have germline RB1 mutation. Identification of RB1 mutations and genetic counseling is essential to assess the risk of developing RB in the patients´ relatives and to prevent the disease. The aim of this study is to assess the frequency/type of RB1 gene mutations in a large cohort of Turkish RB cases. Methods: RB1 gene mutation screening was performed in peripheral blood samples of 219 individuals (122 children with RB/14 family members with RB/83 healthy family members of 47 probands with RB1 mutations) followed in the Istanbul University, Oncology Institute. All 27 exons and close intronic regions of the RB1 gene were sequenced for small deletions and insertions using the Sanger sequencing (2013-2018) or Next Generation Sequencing (2019-2021); large deletions and duplications were investigated both by Multiplex Ligation Probe Amplification (MLPA) and copy number variation (CNV). Correlation with demographic and clinical data were evaluated. Results: After RB1 mutation screening, mutations were detected in 57 (41.9%) of 136 patients. RB1 mutations was observed in 23/84 (27.4%) patients with unilateral RB, in 30/47 (63.8%) bilateral RB, in 3/3 trilateral RB, and1/2 unilateral retinoma. Of these mutations, 45 (78.9%) were small genetic rearrangements and 12 (21.1%) large genetic rearrangements. Frameshift mutations were found in 11, nonsense in 18, splice error in 11, and missense mutation in 1, synonymous substitution in 2, upstream substitution in 2 patients. Ten novel mutations were found. Three of 83 healthy family members also had germline RB1 mutation. The disease was hereditary in 13 (22.8%); and de novo (77.2 %) in 44 of the 57 patients with mutations. Three siblings were found to have RB1 mutation, while their parents did not. Patients diagnosed as infants (RB1 mutation found in 63.2% of 70 infants vs in 36.8% of older ones, p:0.021); those with bilateral/trilateral RB (66 vs 27.4%, p:0.0001); those with light (green-blue) iris color vs dark color (71.4% vs 36.5%. p:0.003) had higher frequency of RB1 gene mutation. There was no significant correlation regarding gender or ICRB stage and RB1 mutation frequency. Conclusions: RB1 gene mutation was found in 41.9% of Turkish children with RB, in 63.8% of bilateral and 27.4% of unilateral RB. 10 novel mutations of the RB1 gene were found according to the Leiden Open Variation Database and the Human Gene Mutation Database.The mutation frequency was significantly higher in patients with bilateral/trilateral RB, in infants, in those with light iris color. In bilateral RB with no RB1 mutation, other genes/RB1 gene methylation and expression status may play a role in the pathogenesis.

Optic pathway gliomas in children: Demographic, clinical characteristics, and results of an adapted protocol

e22016

Background: Optic pathway gliomas (OPG) constitute 1-5% of childhood brain tumors. The presence of neurofibromatosis type 1 (NF-1) is generally associated with more indolent disease. The aim of this study is to evaluate patients with optic pathway gliomas diagnosed/treated/ followed in a single center over 32 years. Methods: The medical files of 85 patients with OPG diagnosed/treated between 1990-2021 in the Istanbul University, Oncology Institute were retrospectively assessed for demographic, clinical characteristics, treatment and outcome. Results: The median age of the 85 patients (42 male, 43 female) was 60 (1-216) months, 53 (62.4%) had NF-1. Seven had diencephalic syndrome (8.2%). According to Dodge classification, 23 (27.1%) had Dodge 1, 30 (35.3%) Dodge 2 and 32 (37.6%) Dodge 3 disease. Median follow up time was 10.5 years (1-31 years). Twenty (23.5%) patients had stable disease and were followed without treatment, 14 patients underwent surgery (5 gross total tumor resection, 2 subtotal resection, 3 ventriculoperitoneal shunt operation, 4 excision/biopsy). 7 patients recieved radiotherapy (RT), none had NF1. 56 patients received chemotherapy (CT) due to severe/progressive clinical symptoms (such as diencephalic syndrome, visual impairment, nystagmus) or radiologic progressive disease. Chemotherapy consisted of an adapted SIOP-LGG regimen: vincristine (VCR) 1.5 mg/m²/dose and carboplatinum 550 mg/m²/dose every 21 days for three courses with weekly VCR, followed by VCR and carboplatinum every 28 days for a total of 12 cycles (3 cycles induction, 9 cycles consolidation). Vinblastin or cisplatinum with etoposide were used for second line or further treatment in progressive disease. One of the seven patients who had diencephalic syndrome and two of the 3 patients with leptomeningeal metastasis died. Ocular findings were recorded in 47 patients: vision was stable in 30 (63.8%), improved in 15 (31.9%), detoriated in 2 (4.3%). Radiology (MRI) revealed stable disease/regression of tumor in 41 patients, and complete regression of spinal metastasis in 1 patient. Endocrinologic follow-up was done and 13(15.2%) recieved hormonal treatment. Ten year overall survival(S) in all patients, in patients with NF1 and without NF1 were 96.5%, 96.1% and 95%, respectively; 10 year event free survival (EFS) in all patients, in patients with NF1 and without NF1 were 80.6%, 90.5% and 60% (p:0.001) respectively. Conclusions: OPG may remain indolent for many years after diagnosis, especially in patients with NF 1. However, these tumors develop progressive characteristics and can cause visual disturbances, endocrine dysfunction, blindness and even death among some of the patients. In young children who are symptomatic/have progressive disease, chemotherapy with an adapted regimen consisting of vincristine and carboplatinum seems to be effective and provides a relatively good quality of life.

Evaluating Pain Management Practices for Cancer Patients among Health Professionals: A Global Survey

Background: Cancer incidence in the world is predicted to increase in the next decade. While progress has been in diagnosis and treatment, much still remains to be done to improve cancer pain therapy, mainly in underserved communities in low-income countries. Objective: To determine knowledge, beliefs, and barriers regarding pain management in both high- and low-income countries (according to the WHO classification); and to learn about ways to improve the current state of affairs. Design: Descriptive survey. Setting/Subjects: Fifty-six countries worldwide; convenience sample of 1639 consisted of 36.8% physicians; 45.1% nurses, and 4.5% pharmacists employed in varied settings. Results: Improved pain management services are key elements. Top barriers include religion factors, lack of appropriate education and training at all levels, nonadherence to guidelines, patients' reluctance to report on pains, over regulation associated with prescribing and access to opioid analgesics, fear of addiction to opioids, and lack of discussions around prognosis and treatment planning. Conclusion: The majority of patients with cancer in low-income countries are undertreated for their pain. Promoting cancer pain accredited program of training and education on pain management for physicians and nurses is crucial, as well as advocating policymakers and the public at large.

Clinical and molecular evaluation of MEFV gene variants in the Turkish population: a study by the National Genetics Consortium

Familial Mediterranean fever (FMF) is a monogenic autoinflammatory disorder with recurrent fever, abdominal pain, serositis, articular manifestations, erysipelas-like erythema, and renal complications as its main features. Caused by the mutations in the MEditerranean FeVer (MEFV) gene, it mainly affects people of Mediterranean descent with a higher incidence in the Turkish, Jewish, Arabic, and Armenian populations. As our understanding of FMF improves, it becomes clearer that we are facing with a more complex picture of FMF with respect to its pathogenesis, penetrance, variant type (gain-of-function vs. loss-of-function), and inheritance. In this study, MEFV gene analysis results and clinical findings of 27,504 patients from 35 universities and institutions in Turkey and Northern Cyprus are combined in an effort to provide a better insight into the genotype-phenotype correlation and how a specific variant contributes to certain clinical findings in FMF patients. Our results may help better understand this complex disease and how the genotype may sometimes contribute to phenotype. Unlike many studies in the literature, our study investigated a broader symptomatic spectrum and the relationship between the genotype and phenotype data. In this sense, we aimed to guide all clinicians and academicians who work in this field to better establish a comprehensive data set for the patients. One of the biggest messages of our study is that lack of uniformity in some clinical and demographic data of participants may become an obstacle in approaching FMF patients and understanding this complex disease.

Clinical characteristics, late effects and outcomes in pineoblastomas in children: a single center experience

BACKGROUND

Pineoblastomas (PB) are rare tumors of the central nervous system and are more common in children. There is no consensus about standard of care. The objective of this study is to analyze the outcome of children with PB.

METHODS

Six patients with PB who were diagnosed between 1990-2012 were evaluated retrospectively. Demographics, age of diagnosis, first complaint, tumor region, diagnosis type, seeding metastasis to the spinal axis or cerebrospinal fluid (CSF), treatment and survival of these patients were recorded.

RESULTS

Three patients had subtotal resection and all patients received chemotherapy and craniospinal irradiation (CSI) after diagnosis. Median follow-up after treatment was 5.5 (range:1-19) years. Two patients are alive with no evidence of disease for 7.5 and 10 years, one of whom was diagnosed with papillary thyroid carcinoma 9.5 years after treatment. One of the patients who died had lived for 19 years after diagnosis.

CONCLUSIONS

Pineoblastomas are rare but very aggressive tumors; more effective treatment strategies are needed. Survivors should be followed up for late effects such as second malignancies and endocrine deficiencies.

Identification of candidate genes in a family with cancer overload by whole-exome sequencing

BACKGROUND

Approximately 120 out of every 1 million children in the world develop cancer each year. In Turkey, 2500-3000 children are diagnosed with new cancer each year. The causes of childhood cancer have been studied for many years. It is known that many cancers in children, as in adults, cause uncontrolled cell growth, and develop as a result of mutations in genes that cause cancer.

METHODS

The investigation of family history within this context in the study, a total of 13 individuals consisting of all children and adults in the family were examined using the whole-exome sequencing (WES) with the individuals who were diagnosed with cancer in the family, who were detected to have different cancer profiles, and defined as high risk and to determine the gene or genes through which the disease has developed.

RESULTS

At the end of the study, a total of 30 variants with a pathogenic record in the family were identified. A total of 10 pathogenic variants belonging to 8 different genes from these variants have been associated with various cancer risks.

CONCLUSIONS

A significant scientific contribution has been made to the mechanism of disease formation by studying a family with a high cancer burden and by finding the genes associated with the disease. In addition, by the results obtained, family members with cancer predisposition were selected after a risk analysis conducted in this family, and the necessary examinations and scans were recommended to provide an early diagnostic advantage.

Effects of different molecular subtypes and tumor biology on the prognosis of medulloblastoma

PURPOSE

Medulloblastoma is one of the most common malignant brain tumors in the pediatric population. Recent studies identified four distinct medulloblastoma subgroups with different molecular alterations and pathways, and natural courses and outcomes. To evaluate the results of surgical and medical treatments of patients with medulloblastoma and compare them among the medulloblastoma subgroups.

METHODS

The clinical and radiological features, medical and surgical management and treatment outcomes and their correlation with molecular subgroups of 58 patients treated for medulloblastoma in the last 20 years were evaluated.

RESULTS

Fifty-eight patients, of whom 35 were male and 23 were female, were evaluated. The median age was 6 years (range, 1-19 years). The most common symptoms were nausea and vomiting (60%). Forty-three percent of the patients had headache and 40% had ataxia. Previous pathology reports revealed that 43 (74%), eight (14%), five (8%), and two (3%) had classic, desmoplastic, desmoplastic/nodular, and anaplastic morphologies, respectively. After the subgroup analyses, five patients (12%) were attributed to the wingless subgroup (WNT) group; 14 (32.5%), to the sonic hedgehog subgroup (SHH) group; and 24 (56%), to the non-WNT non-SHH group. On the basis of immunohistochemical analysis results, 15 patients could not be attributed to any subgroups. The clinical risk groups (average vs high-risk) and age at diagnosis (≥ 3 years vs < 3 years of age) were significant for 5-year event free survival (86% vs 43%, p:0.011 and 59% vs 36%, p:0.039). There was no significant difference in survival or event free survival according to molecular subtypes in this cohort.

CONCLUSION

In corporation of molecular features to the clinicopathologic classification leads to risk-adapted treatment. Although the molecular subgroups did not affect outcome significantly in this study, more studies with larger numbers of patients are needed to understand the tumor pathophysiology of medulloblastoma and design the future medical practice.

Nasopharyngeal carcinoma in children: Multimodal treatment and long-term outcome of 92 patients in a single center over a 28-year period

OBJECTIVES

The aim of the study was to evaluate the long-term outcome and late effects in pediatric patients with nasopharyngeal carcinoma (NPC) treated with neoadjuvant chemotherapy (NACT), followed by radiotherapy (RT).

METHODS

Ninety-two children (65 male, 27 female) diagnosed with NPC between 1989 and 2017 in the Istanbul University, Institute of Oncology were evaluated retrospectively. NACT consisted of three cycles of cisplatin-containing regimen every 3 weeks, followed by RT.

RESULTS

The median age was 13 years (5-18 years). Most had locoregionally advanced disease (stage III/IVA/IVB) and five had distant metastases at presentation. At a median follow-up of 108 months (3-332 months), 5- and 10-year overall survival rates and event-free survival rates were 87.5%, 79.7% and 82.1%, 78.9%, respectively. Three patients with distant metastasis are long-term survivors. Thirteen patients relapsed at a median of 8 months (2-23 months). Hypothyroidism (36%) and xerostomia (25%) were the most frequent long-term treatment-related toxicities. Nine second malignancies developed in eight patients, eight in the irradiated field at a median of 14 years (range 5-26 years), five of whom are long-term survivors after curative surgery.

CONCLUSIONS

Three courses of cisplatin-containing NACT, followed by RT lead to high survival and locoregional control rate in advanced stage NPC in children. Patients with distant metastasis should also be treated with curative intent by systemic chemotherapy and locoregional radiotherapy. Patients should be followed closely for recurrences and long-term morbidities including second malignancies, which may be treated with curative surgeries if diagnosed early.

Treatment results of modified BFM protocol in pediatric high-risk Burkitt lymphoma

BACKGROUND

Chemotherapy with high dose methotrexate is the mainstay of treatment for Burkitt lymphoma (BL), especially to manage central nervous system (CNS) disease. However, methotrexate administration requires close drug level monitoring for appropriate folinic acid rescue, which might not be readily available in all centers. In this study, we assessed the long-term treatment outcomes of a modified Non-Hodgkin lymphoma (NHL)-Berlin-Frankfurt-Munster (BFM) 90 regimen in pediatric high-risk BL without CNS involvement.

METHODS

Between 1999 and 2011, 42 patients (median age: 7 years) with advanced-stage BL were treated with modified NHL-BFM 90 regimen (methotrexate at a dose of 1 g/m2). Demographic data, stage, lactate dehydrogenase (LDH) and treatment results were retrospectively evaluated. The patients were assessed for toxicity, survival and CNS recurrence.

RESULTS

Thirty-six patients had Stage III and six had Stage IV disease, respectively. The median LDH level was 1,432 IU/L. Four patients died of infectious and metabolic complications. One patient had local recurrence at the 48 < sup > th < /sup > month of the follow-up and he is in the second remission for 72 months. In Kaplan-Meier analysis, the overall survival and event-free survival rates at 10 years were found as 90 % and 88 %, respectively. None of our patients died of treatment failure.

CONCLUSIONS

The administration of the reduced dose of methotrexate seems to not compromise treatment success nor increase the risk of CNS recurrence in high-risk BL without CNS involvement. The limitation of the study is that it is not randomized. Our treatment scheme might be considered for centers without methotrexate measurement facility.

Childhood Rhabdomyosarcoma of the Female Genital Tract: Association with Pathogenic DICER1 Variation, Clinicopathological Features, and Outcomes

STUDY OBJECTIVE

Rhabdomyosarcomas (RMSs) of the female genital tract (FGT) have been recently shown to be associated with germline pathogenic variation in DICER1, which can underlie a tumor predisposition disorder. We sought to determine the incidence of a pathogenic variation in DICER1 in a cohort of RMSs of the FGT, as well as to evaluate the clinicopathological features and outcomes of the patients. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: We retrospectively reviewed medical records of the patients diagnosed with RMS of the FGT between 1990 and 2019. Molecular genetic sequencing of the tumor to detect an RNase IIIb domain hot spot mutation in DICER1 samples was performed in 7 patients. Individuals with a missense mutation in the tumor were also screened for a loss of function germline mutation in DICER1.

RESULTS

Of 210 cases of pediatric RMS, 11 arose from the FGT. Molecular genetic sequencing of the tumor samples revealed a somatic missense mutation in the RNase IIIb domain of DICER1 in a total of 3 patients, 2 patients with embryonal RMS of the cervix/uterus, and 1 patient with ovarian embryonal RMS. As a result of genetic testing for the loss of function germline mutation in DICER1, a heterozygous pathogenic variant was also found in 2 of these patients.

CONCLUSION

Despite the limited number of patients, our findings suggest that it is important to be aware of the possible association between RMS of FGT and pathogenic germline DICER1 variants because the detection of this mutation in a patient or relatives can provide the opportunity for surveillance of related conditions that might improve long-term outcomes and survival.

Second malignancies in children with head and neck primary tumors

e22014

Background: Children with primaries in the head and neck region, especially those who recieve radiotherapy (RT) are at increased risk for second malignancies (SM). This study aims to assess the incidence and outcome of SM in children with head and neck primary tumors. Methods: During 1990-2017, 3214 children with cancer were treated in theIstanbul University, Oncology Institute. The primary tumor was in the head and neck region in 1414 (651 brain tumors,289 retinoblastoma,474 other). Survivors followed up for at least 3 years from diagnosis were evaluated for second malignancies. Results: 30 SM were identified in 28 survivors (18 male,10 female) at a median of 12 years (2-26) from diagnosis. The primary diagnosis was nasopharyngeal carcinoma (NPC) in 8, bilateral retinoblastoma (RBS) in 7, embryonal brain tumors (CNST) in 8, Hodgkin lymphoma (HD) in 3, rhabdomyosarcoma(RMS) in 2. Two RBS patients who did not recieve radiotherapy developed pilocytic astrocytoma (at 2 years) and osteosarcoma of the extremity (at 4 years) each, both are alive with no evidence of disease (NED) for 3.5 and 10 years. 26 patients recieved RT: one with CNST developed MDS (at 8 years) and died due to complications after stem cell transplantation (SCT). One with NPC developed PNET of the bladder (at 5 years) and died of disease (DOD). One with relapse HD developed Langerhans cell histiocytosis 2 years after SCTand is with NED for 10 years. The other 23 developed SM in the/proximity of the RT field. These SM were 7 sarcomas (in 4 retinoblastoma,2 NPC, 1 RMS), 6 thyroid cancer (in 2 CNST, 1 RMS, 1 HD, 1 NPC), 3 meningiomas (in 2 CNST, 1 RBS), 5 carcinomas (in 4 NPC, 1 RBS), 1 basal cell carcinoma (in a recurrent re-irradiated CNST, is with NED), 1 peripheral nerve sheath tumor (in 1 HD, DOD), glioblastoma multiforme and non Hodgkin's lymphoma (in the same CNST case, DOD at 6 months). One of the NPC case developed both sarcoma (at 18 years) and carcinoma (at 25 years, NED). The RT dose (20-70 Gy) differed according to diagnosis. All survivors of thyroid cancer are with NED except one who died in an accident; of 3 meningiomas, the one with retinoblastoma who developed malignant meningioma died. Of five carciinomas as SM, two with NPC who developed carcinomas died. Of sarcomas as SM, two with fibrosarcomas are with NED at 10 years each (1NPC, 1 RMS). All patients survived for a median of 3 (0.5-16) years after SM; 16/28 (57%) are with NED at a median of 8 (1-16) years; 12 died at a median of 1.8 (0.5-4.75) years after SM. (1 CNST due to accident, 1 NPC due to infectious complications after a reconstructive surgery, 10 DOD). All SM were detected early during regular surveillance. Conclusions: Children with head and neck primaries are at risk for SM which may occur many years later, especially in RT sites. RT should be avoided when possible such as currently in RBS. Patients need regular surveillance lifelong, for early detection of SM. SM should be treated with curative intent, to achieve long term survival.

Survival Benefit for Individuals With Constitutional Mismatch Repair Deficiency Undergoing Surveillance

Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals.

Neurofibromatosis type 1: Expanded variant spectrum with multiplex ligation-dependent probe amplification and genotype-phenotype correlation in 138 Turkish patients

OBJECTIVE

To investigate the variant spectrum and genotype-phenotype correlations in a Turkish cohort with Neurofibromatosis Type-1 (NF1).

MATERIALS AND METHODS

 We retrospectively investigated the clinical and molecular data of 138 NF1 patients from 129 families who had been followed-up for a median of 3.9 (1.25-18.5) years.

RESULTS

NF1 sequencing revealed 73 different intragenic variants, 19 of which were novel. Seven large deletions were detected by multiplex ligation-dependent probe amplification (MLPA) analyses. The total detection rate of pathogenic NF1 variants was found to be 87.1%. Comparing age groups, cutaneous neurofibromas, freckling, and Lisch nodules were more prevalent in patients older than 12 years (p > .05). Optic glioma detected in 17.3% of the patients and was significantly more common before the age of 6 (p > .001). Other solid tumors developed in 5% of the patients. There was no genotype-phenotype correlation between patients with truncating and nontruncating variants. However, six out of seven patients with large deletions had significant developmental delay, one patient with the c.2970_2972delAAT (p.Met992del) variant had only typical pigmentary features, and another patient with the c.4267A > G (p.Lys1423Glu) variant had CALMs, freckling, neurofibromas, and Noonan-like phenotype.

CONCLUSIONS

We described 19 novel variants and seven large deletions in NF1. Applying MLPA assay in NF1 is useful in expanding the molecular diagnosis. Although very limited genotype-phenotype correlation has been reported in NF1, the fact that specific phenotypic findings were observed in our patients with large deletions and two intragenic variants supports the studies published recently.

Epidemiology and survival of childhood cancer in Turkey

INTRODUCTION

The aim of this study is to evaluate demographics, clinical data, and survival rates of children with cancer over 22 years, and to compare the outcomes, before and after a national health reform was performed.

MATERIAL AND METHODS

Files of patients, aged 0-19 years, diagnosed with cancer at the Istanbul University Oncology Institute during 1990-2012 were evaluated retrospectively.

RESULTS

The mean age at diagnosis of 2413 patients was 7.5 ± 5.1 years (range 3 days to 19 years). Male/female ratio was 1.26. After 2002, the number of patients diagnosed at a localized/low-risk stage compared to advanced stage significantly increased (60.7% vs 65.1%, P = .03). Comparing the period before 2002 to after 2002, a lower percentage of patients were diagnosed with advanced stage non-Hodgkin lymphoma (62.1% vs 45.1%, P = .03), retinoblastoma (9.5% vs 1.4%, P = .005), soft tissue sarcomas (52.1% vs 38.3%, P = .01), neuroblastoma (82.4% vs 56.2%, P = .005), and carcinomas (72.9% vs 65.4%, P = .04) after 2002. The 5-year survival rate of all patients during the entire period was 74.4%. The survival rate significantly increased for non-Hodgkin lymphoma (63.7% vs 91.8%, P < .0001), neuroblastoma (46.8% vs 70.5%, P = .025), and renal tumors (70% vs 92.3%, P = .013) after 2002.

CONCLUSIONS

The increase in patients diagnosed at a localized/low-risk stage and the increase in survival of some types of cancer over years is promising. The national health care reform, enabling patients to easily access free health services, increased awareness, improvement in oncological treatment, and supportive care may have contributed to the progress achieved, and may be a model for other developing countries.

Fertility preservation for female patients with childhood, adolescent, and young adult cancer: recommendations from the PanCareLIFE Consortium and the International Late Effects of Childhood Cancer Guideline Harmonization Group

Female patients with childhood, adolescent, and young adult cancer are at increased risk for fertility impairment when treatment adversely affects the function of reproductive organs. Patients and their families desire biological children but substantial variations in clinical practice guidelines reduce consistent and timely implementation of effective interventions for fertility preservation across institutions. As part of the PanCareLIFE Consortium, and in collaboration with the International Late Effects of Childhood Cancer Guideline Harmonization Group, we reviewed the current literature and developed a clinical practice guideline for fertility preservation in female patients who were diagnosed with childhood, adolescent, and young adult cancer at age 25 years or younger, including guidance on risk assessment and available methods for fertility preservation. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to grade the available evidence and to form the recommendations. This clinical practice guideline leverages existing evidence and international expertise to develop transparent recommendations that are easy to use to facilitate the care of female patients with childhood, adolescent, and young adult cancer who are at high risk for fertility impairment. A complete review of the existing evidence, including a quality assessment, transparent reporting of the guideline panel's decisions, and achievement of global interdisciplinary consensus, is an important result of this intensive collaboration.

Palliative Care in High and Low Resource Countries

Palliative Care (PC) is defined by the World Health Organization (WHO) as a support provided by multiple disciplines in order to improve the quality of life of both patients and their caregivers, throughout the disease course, from diagnosis to end-of-life. PC aims to prevent and treat symptoms and side effects of the disease and its treatment. PC is well developed in most high- -income countries; however in most low-income settings, where approximately 80% of patients with cancer requiring PC care for advanced disease live, PC services are still uncommon. Health indicators monitoring global PC development are policy, education, use of medicines, service provision and professional activity. Globally, PC development may be categorized as Group 1 (no known hospice-PC activity), Group 2 (capacity-building activity), Groups 3a Isolated PC provided, 3b Generalized PC provided, 4a hospice-PC services at a stage of integration into regular service provision, and 4b hospice-PC services at a stage of advanced integration into regular service provision. Spirituality is an essential element of patient-centered PC. The use of Complementary and Traditional Medicine (CTM) in Middle Eastern countries is widespread. There are wide discrepancies in cancer care and PC in many regions of the world. The Individualized Care Planning and Coordination (ICPC) Model is designed to facilitate the advance care planning with continuity of all the measures like symptom control or emotional, social and spiritual care of both the patient and the family during the disease steps like relapse or end of life.

RARE-55. CHALLENGES AND SPECIFIC STRATEGIES FOR CONSTITUTIONAL MISMATCH REPAIR DEFICIENCY SYNDROME IN LOW RESOURCE SETTINGS. ON BEHALF OF THE INTERNATIONAL RRD CONSORTIUM IN LOW RESOURCE SETTINGS PANEL

Germline biallelic mutations in one of the mismatch repair genes (MSH2/MSH6/MLH1/PMS2 results in constitutional mismatch repair deficiency (CMMRD), a condition associated with multiple tumors arising from multiple organs during childhood, and these individuals rarely reach adulthood. The paucity of information with respect to these conditions leads to mismanagement and may be a factor in the high mortality of patients with CMMRD. Two international consortia, the European CARE4CMMRD, and the international replication repair deficiency (RRD) consortium, are addressing the many challenges associated with this condition. To address specific issues surrounding the management of CMMRD in low and middle income countries (LMIC), a multidisciplinary taskforce of 11 specialists from nine countries was formed. Preliminary conclusions are: 1) Immunohistochemistry for CMMRD should be considered for all patients with suggestive clinical features. In countries where CMMRD is common, malignant gliomas, colon cancers and T cell lymphomas should be stained routinely as the prevalence of CMMRD in these tumors can exceed 40%. 2) Temozolomide should not be used in the management of malignant glioma. By contrast, preclinical studies have suggested increased sensitivity to nitrosoureas. For the management of CMMRD related lymphoma and leukemia, mercaptopurines should not be avoided or discontinued as a part of the standard of care before more data are collected. 3) Management with checkpoint inhibitors should be limited to centers with intensive care units and expertise in complex supportive care to manage side effects of immune therapy. 4) Surveillance protocols have demonstrated long term survival benefits and should be implemented in LMIC.

Lymphoma Predisposing Gene in an Extended Family: CD70 Signaling Defect

Genome-wide sequencing studies in pediatric cancer cohorts indicate that about 10% of patients have germline mutations within cancer predisposition genes. Within this group, primary immune deficiencies take the priority regarding the vulnerability of the patients to infectious agents and the difficulties of cancer management. On the other hand, early recognition of these diseases may offer specific targeted therapies and hematopoietic stem cell transplantation as an option. Besides therapeutic benefits, early diagnosis will provide genetic counseling for the family members. Within this context, an extended family with multiple consanguineous marriages and affected individuals, who presented with combined immune deficiency (CID) and/or Hodgkin lymphoma phenotype, were examined by exome sequencing. A pathogenic homozygous missense CD70 variation was detected (NM_001252.5:c332C>T) in concordance with CD70 phenotype and familial segregation was confirmed. CD70 variations in patients with CID and malignancy have very rarely been reported. This paper reports extended family with multiple affected members with CID and malignancy carrying a missense CD70 variation, and reviews the rare cases reported in the literature. Primary immune deficiencies appear to be a potential cause for pediatric cancers. Better focusing on these inborn disorders to prevent or make an early diagnosis of malignant transformation and reduce mortalities is important.

Position paper: Challenges and specific strategies for constitutional mismatch repair deficiency syndrome in low-resource settings

Germline biallelic mutations in one of the mismatch repair genes, mutS homolog 2, mutS homolog 6, mutL homolog 1, or postmeiotic segregation increased 2, result in one of the most aggressive cancer syndromes in humans termed as constitutional mismatch repair deficiency (CMMRD). Individuals with CMMRD are affected with multiple tumors arising from multiple organs during childhood, and these individuals rarely reach adulthood without specific interventions. The most common tumors observed are central nervous system, hematological, and gastrointestinal malignancies. The incidence of CMMRD is expected to be high in low-resource settings due to a high rate of consanguinity in these regions, and it is thought to be underrecognized and consequently underdiagnosed. This position paper is therefore important to provide a summary of the current situation, and to highlight the necessity of increasing awareness, diagnostic criteria, and surveillance to improve survival for patients and family members.

The COVID-19 pandemic: A rapid global response for children with cancer from SIOP, COG, SIOP-E, SIOP-PODC, IPSO, PROS, CCI, and St Jude Global

The COVID-19 pandemic is one of the most serious global challenges to delivering affordable and equitable treatment to children with cancer we have witnessed in the last few decades. This Special Report aims to summarize general principles for continuing multidisciplinary care during the SARS-CoV-2 (COVID-19) pandemic. With contributions from the leadership of the International Society for Pediatric Oncology (SIOP), Children's Oncology Group (COG), St Jude Global program, and Childhood Cancer International, we have sought to provide a framework for healthcare teams caring for children with cancer during the pandemic. We anticipate the burden will fall particularly heavily on children, their families, and cancer services in low- and middle-income countries. Therefore, we have brought together the relevant clinical leads from SIOP Europe, COG, and SIOP-PODC (Pediatric Oncology in Developing Countries) to focus on the six most curable cancers that are part of the WHO Global Initiative in Childhood Cancer. We provide some practical advice for adapting diagnostic and treatment protocols for children with cancer during the pandemic, the measures taken to contain it (e.g., extreme social distancing), and how to prepare for the anticipated recovery period.

Rhabdomyosarcoma of the female genital tract: Long-term outcome and association with DICER1 variation

10538

Background: Rhabdomyosarcoma (RMS) of the female genital tract is rare, accounting for 3.5% of cases of rhabdomyosarcomas. Germline DICER1 mutations are associated with predisposition to pleuropulmonary blastoma and other tumors including sarcomas. Recently DICER1-associated RMS of the uterus/ovary has ben reported.. The aim of this study is to evaluate demographic characteristics, molecular pathogenesis, treatment and long term outcome of female genital tract rhabdomyosarcoma. Methods: Files of children with RMS of the female genital tract diagnosed at the Istanbul University, Oncology Institute during 1990-2019 were reviewed. Molecular genetic sequencing was performed by polymerase chain reaction amplification of genomic DNA extracted from the formalin-fixed, paraffin embedded tumors, followed by Sanger sequencing. Genetic testing for DICER1 variants of the proband and family members was performed if DICER1 mutation was detected in the tumor of the proband. Results: Of 210 RMS cases, 11 arose from the female genital tract. The median age at diagnosis was 52 months (10 months-15 years). Primary sites were vaginal (n = 5), uterus (n = 4), and ovary(n = 2). Presenting symptoms included vaginal mass (n = 6), vaginal bleeding (n = 5), and abdominal pain (n = 3). Four had group 1, five group 3, two group 2 disease and all received chemotherapy (vincristine, actinomycinD + cyclophosphamide).Three received radiotherapy; three underwent hysterectomy. DICER1 mutation was detected in tumor tissue in three patients:[ c.5113G > A (p.E1705K); c.5428G > T (p.D1810Y); c.1870C > T (p.Arg624Ter)] Genetic testing revealed germline DICER1 pathogenic variation in two patients and their family members, one of whom had cystic nephroma in infancy and history of Wilms tumor in an uncle. They were referred for surveillance for the DICER1 related diseases. A patient with metachronous bilateral ovarian RMS died. Two are married, one has children. The 5 year survival for RMS of the female genital tract was 85.7 % at a median follow-up of 34 (4-298) months. Conclusions: Rhabdomyosarcoma of the female genital tract is associated with a favorable prognosis, however some individuals undergo aggressive local therapies. Individuals with RMS of the female genital tract should be tested for DICER1 pathogenic variation. The detection of a DICER1 mutation in an individual or family members is important to facilitate surveillance for related tumors, so that they may be detected at the earliest possible stage, potentially increasing survival and decreasing risks of late effects.

High levels of global genome methylation in patients with retinoblastoma

Retinoblastoma is a tumor of the embryonic neural retina in young children. The DNA methyltransferase 1 (DNMT1) gene has been demonstrated to be transcriptionally activated in cells lacking retinoblastoma 1 (RB1). Thus, there is a direct interaction between DNMT1 and RB1 in vivo. The present study hypothesized that uncontrolled DNMT1, DNMT2 and DNMT3 expression may lead to a high level of global genome methylation causing a second hit or where both alleles are altered, in RB1 and/or inactivation of other genes in retinal cells. To test this, the global genome methylation levels were analyzed in 69 patients with retinoblastoma, as well as 26 healthy siblings and 18 healthy unrelated children as the control groups. Peripheral blood and tumor tissue samples were obtained from 32 patients. The expression levels of DNMT genes were also determined in cell lines. Based on the median levels of global genome methylation in patients, higher genome-wide methylation levels in peripheral blood were associated with a 3.33-fold increased risk for retinoblastoma in patients compared with all healthy controls (95% confidence interval, 0.98–11.35; P<0.0001). The level of global genome methylation and the expression of DNMT genes were increased in the WERI-RB-1 cell line, which has a mutated RB1 gene, compared with a wild-type RB1-expressing cell line. These results supported the hypothesis that epigenetic alterations, as well as mutations in RB1, may be associated with the oncogenesis and inheritance of retinoblastoma. The repression of genes that interact with RB1, such as the DNMT gene family, may be important in patients with retinoblastoma with alterations in RB1, and may serve a role in the treatment and regression of retinoblastoma.

DICER1 Hotspot Mutations in Pleuropulmonary Blastoma: A Case Series From a Tertiary Center

Pleuropulmonary blastoma (PPB) is a potentially aggressive, rare childhood neoplasia. We investigated histopathological features, survival, and DICER1 hotspot mutations among PPB patients. Archive records at our institution were reviewed, covering a 20-year period. Thirteen children (6 males and 7 females) with a mean age of 30.5 (range 6-83) months were included. The tumor subtypes were type I in 6 (46%), type II in 4 (31%), and type III in 3 (23%). Only tumors with type II and type III histology showed anaplasia (4/7, 57%). Median follow-up was 28 (range 9-216) months. Three-year overall survival rate was 83.3% and 3-year progression-free survival rate was 25%. Progression was seen in 60% (3/5) of type I and 66.7% (4/6) of type II and type III cases. Two patients died of disseminated disease at 9 and 44 months. Hotspot missense mutations on DICER1 gene were detected in all 11 patients with available tumor tissue. We found an additional novel germline loss-of-function mutation (c.5436dupT; p.E1813*) in 1 case. To the best of our knowledge, this is the first study to investigate hotspot missense mutations on DICER1 gene among the largest series of Turkish children with PPB.