ESTRO-SIOPE guideline: Clinical management of radiotherapy in atypical teratoid/rhabdoid tumors (AT/RTs).

BACKGROUND AND PURPOSE: Treatment of patients with atypical teratoid/rhabdoid (AT/RT) is challenging, especially when very young (below the age of three years). Radiotherapy (RT) is part of a complex trimodality therapy. The purpose of this guideline is to provide appropriate recommendations for RT in the clinical management of patients not enrolled in clinical trials. MATERIALS AND METHODS: Nine European experts were nominated to form a European Society for Radiotherapy and Oncology (ESTRO) guideline committee. A systematic literature search was conducted in PubMed/MEDLINE and Web of Science. They discussed and analyzed the evidence concerning the role of RT in the clinical management of AT/RT. RESULTS: Recommendations on diagnostic imaging, therapeutic principles, RT considerations regarding timing, dose, techniques, target volume definitions, dose constraints of radiation-sensitive organs at risk, concomitant chemotherapy, and follow-up were considered. Treating children with AT/RT within the framework of prospective trials or prospective registries is of utmost importance. CONCLUSION: The present guideline summarizes the evidence and clinical-based recommendations for RT in patients with AT/RT. Prospective clinical trials and international, large registries evaluating modern treatment approaches will contribute to a better understanding of the best treatment for these children in future.

Radiation Therapy Plays an Important Role in the Treatment of Atypical Teratoid/Rhabdoid Tumors: Analysis of the EU-RHAB Cohorts and Their Precursors.

PURPOSE: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare malignancy of the central nervous system in young children with a dismal prognosis. Prognostic markers have been extensively investigated but have not been validated. The role of radiation therapy (RT) remains controversial. We evaluated the impact of RT as part of multimodality treatment by analyzing data of a European AT/RT cohort. METHODS AND MATERIALS: We retrospectively analyzed data of the European Registry for Rhabdoid Tumors and its precursors. Primary endpoints were progression-free survival (PFS) and overall survival (OS). Potential impact of prognostic factors was analyzed using univariable and multivariable Cox regression analyses with RT as a time-dependent factor. RESULTS: Data of 186 children (118 male, 68 female) treated from 1990 to 2016 were evaluable. The median age at diagnosis was 1.57 years (range, 0.01-26.70 years); 47% (87/186) of the patients were under the age of 18 months. Sixty-nine percent (128/186) received RT (focal RT, n = 93; craniospinal treatment with local boost, n = 34; spinal irradiation, n = 1). The median follow-up duration of the entire cohort was 1.73 years (range, 0.06-20.11 years). The estimated PFS and OS rates were 48% (95% CI, 41%-55%) and 72% (95% CI, 65%-78%) at 1 year and 33% (95% CI, 26%-40%) and 49% (95% CI, 41%-56%) at 2 years, respectively. On multivariable analysis, RT was an independent significant prognostic factor for PFS (hazard ratio, 0.45; 95% CI, 0.27-0.75; P = .002) and OS (hazard ratio, 0.54; 95% CI, 0.32-0.93; P = .025). CONCLUSIONS: This analysis confirms the relevance of local therapies. RT was an independent prognostic factor for outcomes in children experiencing AT/RT. However, long-term sequelae have to be carefully evaluated and considered given the young age at time of RT.

Radiotherapy for Atypical Teratoid/Rhabdoid Tumor (ATRT) on the Pediatric Proton/Photon Consortium Registry (PPCR).

PURPOSE: Atypical teratoid/rhabdoid tumors (ATRT) of the central nervous system (CNS) are rare tumors with a poor prognosis and variable use of either focal or craniospinal (CSI) radiotherapy (RT). Outcomes on the prospective Pediatric Proton/Photon Consortium Registry (PPCR) were evaluated according to RT delivered. METHODS: Pediatric patients receiving RT were prospectively enrolled on PPCR to collect initial patient, disease, and treatment factors as well as provide follow-up for patient outcomes. All ATRT patients with evaluable data were included. Kaplan-Meier analyses with log-rank p-values and cox proportional hazards regression were performed. RESULTS: The PPCR ATRT cohort includes 68 evaluable ATRT patients (median age 2.6 years, range 0.71-15.40) from 2012 to 2021. Median follow-up was 40.8 months (range 3.4-107.7). Treatment included surgery (65% initial gross total resection or GTR), chemotherapy (60% with myeloablative therapy including stem cell rescue) and RT. For patients with M0 stage (n = 60), 50 (83%) had focal RT and 10 (17%) had CSI. Among patients with M + stage (n = 8), 3 had focal RT and 5 had CSI. Four-year overall survival (OS, n = 68) was 56% with no differences observed between M0 and M + stage patients (p = 0.848). Local Control (LC) at 4 years did not show a difference for lower primary dose (50-53.9 Gy) compared to ≥ 54 Gy (73.3% vs 74.7%, p = 0.83). For patients with M0 disease, four-year OS for focal RT was 54.6% and for CSI was 60% (Hazard Ratio 1.04, p = 0.95. Four-year event free survival (EFS) among M0 patients for focal RT was 45.6% and for CSI was 60% (Hazard Ratio 0.71, p = 0.519). For all patients, the 4-year OS comparing focal RT with CSI was 54.4% vs 60% respectively (p = 0.944), and the 4-year EFS for focal RT or CSI was 42.8% vs 51.4% respectively (p = 0.610). CONCLUSION: The PPCR ATRT cohort found no differences in outcomes according to receipt of either higher primary dose or larger RT field (CSI). However, most patients were M0 and received focal RT. A lower primary dose (50.4 Gy), regardless of patient age, is appealing for further study as part of multi-modality therapy.

Targeting the TP53/MDM2 axis enhances radiation sensitivity in atypical teratoid rhabdoid tumors.

Atypical teratoid rhabdoid tumor (ATRT) is a highly aggressive pediatric brain tumor. Despite radiation, aggressive chemotherapy and autologous stem cell rescue, children usually have a poor survival time. In the present study, the role of TP53/MDM2 interaction in ATRT was investigated. A functional genomic screen identified the TP53/MDM2 axis as a therapeutic target in the central nervous system (CNS) ATRT. Gene expression analysis revealed that all ATRT sub­groups expressed high levels of MDM2, which is a negative regulator of TP53. Using cell viability, colony formation and methylcellulose assays it was found that genetic MDM2 inhibition with short hairpin RNA or chemical MDM2 inhibition with small molecule inhibitors, Nutlin3 and idasanutlin (RG7388) decreased the growth of ATRT cell lines. Furthermore, idasanutlin significantly decreased the growth of intracranial orthotopic ATRT brain tumors, as evaluated using T2 MRI, and prolonged survival time relative to control animals. MRI of intracranial tumors showed that diffusion coefficient, an effective marker for successful treatment, significantly increased with idasanutlin treatment showing tumor necrosis/apoptosis. Immunohistochemistry revealed an increased number of caspase­3­positive cells in the idasanutlin treatment group, confirming the induction of apoptosis in vivo. Using flow cytometry and western blot analysis we show that inhibition of MDM2 enhanced radiation sensitivity in vitro by potentiating DNA damage via the induction of the TP53/Bax/Puma proapoptotic axis. Furthermore, DNA damage was associated with increased mitochondrial reactive oxygen species accumulation. The present study demonstrated that MDM2 expression level was increased in ATRT patient samples and MDM2 inhibition suppressed ATRT cell growth in vitro, and leads to apoptosis in vivo. MDM2 inhibition potentiates DNA damage and sensitizes ATRT cells to radiation. These findings highlight the TP53/MDM2 axis as a rational therapeutic target in CNS ATRT.

Adult Pineal Region Atypical Teratoid Rhabdoid Tumor: A Case for Aggressive Surgical and Chemoradiation Management with Comprehensive Literature Review.

BACKGROUND: Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant central nervous system neoplasm classified as an embryonal grade IV neoplasm by the World Health Organization. ATRT generally occurs in children younger than 3 years, with 85 pathologically confirmed cases reported in adults. It is most commonly supratentorial, with only 9 confirmed adult cases localized to the pineal region. CASE DESCRIPTION: The case is described of a 29-year-old man with a history of chronic migraines and a previously negative computed tomography scan of the head presenting with worsening headaches and new-onset diplopia with upward gaze palsy. Computed tomography and magnetic resonance imaging showed a hemorrhagic pineal mass with extension into the right thalamus. After resection, the immunohistochemical staining and cytogenetic profile proved consistent with ATRT, making it the ninth reported case of pineal ATRT in an adult, which was treated aggressively with good outcome. CONCLUSIONS: Adult ATRT is rare, especially in the pineal region, with only 9 cases reported. Because of the aggressiveness, ATRT must be considered in the differential diagnosis of pineal region lesions because early diagnosis and aggressive treatment are key to prolonged survival.

Radiological pseudoprogression post-radiotherapy in a child with pineal germ cell tumour.

Little is known about pseudoprogression in brain tumours other than gliomas. A 9-year-old male child with a pineal teratoma/germinoma underwent surgical resection followed by adjuvant chemo-radiotherapy. The magnetic resonance imaging scan 4 months post-radiotherapy showed a contrast-enhancing lesion within the surgical cavity suspicious of recurrence. These radiological findings subsequently resolved without any specific intervention. The child continues in remission 2 years post-treatment. This case illustrates the occurrence of pseudoprogression post-radiotherapy in intracranial GCT and highlights an unmet need for greater implementation of functional imaging techniques in paediatric neuro-oncology to avoid undue discontinuation of effective treatments or inappropriate enrolment in clinical trials.

Effect of early radiotherapy initiation and high-dose chemotherapy on the prognosis of pediatric atypical teratoid rhabdoid tumors in different age groups.

PURPOSE: The optimal treatment strategy for pediatric atypical teratoid rhabdoid tumor (ATRT) is inconclusive. This study evaluated the prognostic value of early radiotherapy (RT) and high-dose chemotherapy with autologous stem cell rescue (HDC/ASCR) in pediatric ATRT. METHODS: This pooled analysis included ATRT patients treated at our institution and from other studies who were identified by a search of the PubMed electronic database. The effect of patient demographics and treatment profiles on progression-free survival (PFS) and overall survival (OS) were analyzed using Cox regression. RESULTS: Overall, 34 patients from our institution and 436 patients from 35 published studies were included. In multivariable analysis, patients with gross total resection (GTR), early RT (time to RT interval < 2 months), and HDC/ASCR had both better PFS [hazard ratio (HR) 0.46, p[Formula: see text] 0.001; HR 0.64, p = 0.011; and HR 0.51, p = 0.005, respectively] and OS (HR 0.55, p = 0.002; HR 0.48, p = 0.004; and HR 0.42, p < 0.001, respectively). For patients aged < 3 years, both RT and HDC/ASCR were significant favorable factors for PFS (HR 0.32 and 0.46, respectively) and OS (HR 0.40 and 0.36, respectively), while early RT was not prognostic. For patients aged ≥ 3 years, early RT was significantly associated with better PFS (HR 0.51) and HDC/ASCR did not affect PFS, and neither was related to OS. CONCLUSION: Both early RT initiation and HDC/ASCR were important components in the treatment of pediatric ATRT. However, the optimal treatment strategies might differ by age.

Targeted and Selective Treatment of Pluripotent Stem Cell-derived Teratomas Using External Beam Radiation in a Small-animal Model.

The growing number of victims of "stem cell tourism," the unregulated transplantation of stem cells worldwide, has raised concerns about the safety of stem cell transplantation. Although the transplantation of differentiated rather than undifferentiated cells is common practice, teratomas can still arise from the presence of residual undifferentiated stem cells at the time of transplant or from spontaneous mutations in differentiated cells. Because stem cell therapies are often delivered into anatomically sensitive sites, even small tumors can be clinically devastating, resulting in blindness, paralysis, cognitive abnormalities, and cardiovascular dysfunction. Surgical access to these sites may also be limited, leaving patients with few therapeutic options. Controlling stem cell misbehavior is, therefore, critical for the clinical translation of stem cell therapy. External beam radiation offers an effective means of delivering targeted therapy to decrease the teratoma burden while minimizing injury to surrounding organs. Additionally, this method avoids genetic manipulation or viral transduction of stem cells-which are associated with additional clinical safety and efficacy concerns. Here, we describe a protocol to create pluripotent stem cell-derived teratomas in mice and to apply external beam radiation therapy to selectively ablate these tumors in vivo.

Primary Mediastinal HER2-positive Apocrine Carcinoma in Mature Teratoma Treated With Anti-HER2 Therapy and Chemoradiation.

BACKGROUND: There are no established guidelines for the management of apocrine carcinomas of the breast; they are treated as a non-specific type of breast cancer. CASE REPORT: We report on the case of a 40-year-old man who developed primary mediastinal apocrine carcinoma overexpressing human epidermal growth factor-2 (HER2). The patient initially underwent complete resection of a mediastinal mature teratoma with a focal apocrine carcinoma component. Two years after surgery, relapse was detected in multiple mediastinal lymph nodes. He received induction chemotherapy including docetaxel, trastuzumab, and pertuzumab; consolidative concurrent chemoradiation was added after six cycles. A complete response was confirmed using computed tomography following this multimodal therapy. After chemoradiation, adjuvant trastuzumab and pertuzumab were administered for 1 year and the patient has since had no evidence of progressive disease. CONCLUSION: A multi-modal regimen that includes an anti-HER2 agent appears to be a promising treatment for patients with HER2-positive extramammary apocrine carcinoma.

Supratentorial Atypical Rhabdoid Teratoid Tumor ­ A Case Report

Atypical rhabdoid teratoid tumors (ARTTs) are rare embryonic tumors, usually localized in the posterior fossa and diagnosed in children under 3 years-old. The treatment includes surgical resection, radio and chemotherapy, and the prognostic is unfavorable, with an average median survival of 1 year. We present the case of a 3-year-old patient, with history of headache and vomiting, followed by absence seizures, temporal automatism, syncope accompanied by sialorrhea and sphincteric loss succeeded by a postictal period. Surgical excision was performed and the anatomopathological study confirmed ARTT. The ARTTs are embryonic tumors, a category in which medulloblastoma and primitive neuroectodermal tumors (PNETs) represent the most common central nervous system (CNS) malignancies in childhood.

Tumores teratóides rabdóides atípicos (TTRA) são tumores embrionários raros, geralmente localizados na fossa posterior e diagnosticados em crianças com menos de 3 anos de idade. O tratamento inclui ressecção cirúrgica, radio e quimioterapia. Contudo, o prognóstico é desfavorável, com uma sobrevida média de 1 ano. Apresentamos o caso de um paciente de 3 anos de idade, com quadro de cefaléia e vômitos, companhados por automatismo temporal e perda de consciência, seguidos por período pós-ictal. A ressonância nuclear magnética (RNM) do encéfalo evidenciou lesão frontal compatível com tumor intra-axial, efeito de massa local e invasão do corpo caloso. Foi realizada excisão cirúrgica, e o estudo anatômico-patológico confirmou TTRA. Os TTRA são tumores embrionários, categoria na qual o meduloblastoma e os tumores neuroectodermais primitivos representam as malignidades mais comuns no sistema nervoso central de crianças.

Brainstem Injury in Pediatric Patients With Posterior Fossa Tumors Treated With Proton Beam Therapy and Associated Dosimetric Factors.

PURPOSE: Proton radiation therapy is commonly used in young children with brain tumors for its potential to reduce late effects. However, some proton series report higher rates of brainstem injury (0%-16%) than most photon series (2.2%-8.6%). We report the incidence of brainstem injury and a risk factor analysis in pediatric patients with posterior fossa primary tumors treated with proton radiation therapy at our institution. METHODS AND MATERIALS: The study included 216 consecutive patients treated between 2000 and 2015. Dosimetry was available for all but 4 patients. Grade 2 to 5 late brainstem toxicity was assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. RESULTS: The histologies include medulloblastoma (n=154, 71.3%), ependymoma (n=56, 25.9%), and atypical teratoid rhabdoid tumor (n=6, 2.8%). The median age at irradiation was 6.6 years (range, 0.5-23.1 years); median dose, 54 gray relative biological effectiveness (Gy RBE) (range, 46.8-59.4 Gy RBE); and median follow-up period, 4.2 years (range, 0.1-15.3 years) among 198 survivors. Of the patients, 83.3% received chemotherapy; 70.4% achieved gross total resection. The crude rate of injury was 2.3% in all patients, 1.9% in those with medulloblastoma, 3.6% in those with ependymoma, and 0% in those with atypical teratoid rhabdoid tumor. The 5-year cumulative incidence of injury was 2.0% (95% confidence interval, 0.7%-4.8%). The median brainstem dose (minimum dose received by 50% of brainstem) in the whole cohort was 53.6 Gy RBE (range, 16.5-56.8 Gy RBE); maximum point dose within the brainstem (Dmax), 55.2 Gy RBE (range, 48.4-60.5 Gy RBE); and mean dose, 50.4 Gy RBE (range, 21.1-56.7 Gy RBE). In the 5 patients with injury, the median minimum dose received by 50% of the brainstem was 54.6 Gy RBE (range, 50.2-55.1 Gy RBE); Dmax, 56.2 Gy RBE (range, 55.0-57.1 Gy RBE); mean dose, 51.3 Gy RBE (range, 45.4-54.4 Gy RBE); and median volume of the brainstem receiving ≥55 Gy RBE (V55), 27.4% (range, 0%-59.4%). Of the 5 patients with injury, 4 had a brainstem Dmax in the highest quartile (≥55.8 Gy RBE, P = .016) and a V55 in the highest tertile (>6.0%) of the cohort distribution (P = .047). Of the 5 patients with injury, 3 were aged >6 years (age range, 4.1-22.8 years), and 4 of 5 patients received chemotherapy and achieved gross total resection. CONCLUSIONS: The incidence of injury in pediatric patients with posterior fossa tumors is consistent with previous reports in the photon setting. Our data suggest that when Dmax and V55 are kept <55.8 Gy RBE and ≤6.0%, respectively, the 5-year rate of radiation brainstem injury would be <2%.

Atypical teratoid rhabdoid tumor of the central nervous system: Case series from a regional Tertiary Care Cancer Centre in South India.

BACKGROUND: Atypical teratoid rhabdoid tumors (AT/RT) constitute a rare group of pediatric brain tumors. AIM: To study the clinical, histopathological, and immunohistochemical (IHC) profile, management and outcome of children with AT/RT of the central nervous system who presented between the years 2007 and 2015 in a regional tertiary care center in South India. MATERIALS AND METHODS: This was a retrospective study. Demographic and clinical data were obtained from the clinical case files. Archived slides and tissue blocks were retrieved. All cases had hematoxylin and eosin stained sections. IHC was available in all the cases. RESULTS: There were eight cases with the mean age of presentation being 4 years (range: 4 months to 15 years) and with slight male predominance (male:female = 1.66:1). Most of the presenting complaints were due to raised intra-cranial tension. The median duration of symptoms was 0.75 months. About 62.5% of the tumors were infratentorial in location. The tumors were heterogeneous showing variable expression of cytokeratin, epithelial membrane antigen, glial fibrillary acid protein, and synaptophysin. Loss of integrase interactor-1 expression was demonstrated in seven cases in which it was done. Multimodal treatment comprising surgical resection, radiotherapy and chemotherapy was tailored based on location of tumor, resectability and patient's age. The median overall survival was 2.5 months (range: 1.5-30 months). CONCLUSION: Awareness of this tumor is important as it portends a poor outcome in most patients, in spite of multi-modal treatment. Several new molecules which aim to prolong survival and improve quality of life are being developed to combat this enigmatic tumor.

Brief Report: External Beam Radiation Therapy for the Treatment of Human Pluripotent Stem Cell-Derived Teratomas.

Human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced PSCs (hiPSCs), have great potential as an unlimited donor source for cell-based therapeutics. The risk of teratoma formation from residual undifferentiated cells, however, remains a critical barrier to the clinical application of these cells. Herein, we describe external beam radiation therapy (EBRT) as an attractive option for the treatment of this iatrogenic growth. We present evidence that EBRT is effective in arresting growth of hESC-derived teratomas in vivo at day 28 post-implantation by using a microCT irradiator capable of targeted treatment in small animals. Within several days of irradiation, teratomas derived from injection of undifferentiated hESCs and hiPSCs demonstrated complete growth arrest lasting several months. In addition, EBRT reduced reseeding potential of teratoma cells during serial transplantation experiments, requiring irradiated teratomas to be seeded at 1 × 103 higher doses to form new teratomas. We demonstrate that irradiation induces teratoma cell apoptosis, senescence, and growth arrest, similar to established radiobiology mechanisms. Taken together, these results provide proof of concept for the use of EBRT in the treatment of existing teratomas and highlight a strategy to increase the safety of stem cell-based therapies. Stem Cells 2017;35:1994-2000.

Sinonasal teratocarcinosarcoma: a case report.

BACKGROUND: Sinonasal teratocarcinosarcoma is a rare and aggressive malignancy with histological features of both carcinosarcoma and teratoma. The optimal management of this malignancy is unclear, with most patients being managed by a combination of surgery and radiotherapy. CASE PRESENTATION: We describe an 83-year-old white woman with sinonasal teratocarcinosarcoma of her left nasal cavity treated with surgical debulking initially with radiological evidence of residual disease which was treated with radiotherapy (60 Gy in 30 fractions). A follow-up examination at 2 years showed no evidence of recurrence. CONCLUSIONS: In cases of sinonasal teratocarcinosarcoma with residual disease post-surgery, radiotherapy alone can be an effective option.

[Prognostic Impact of Radiation Therapy and Molecular Classification of Infant Atypical Teratoid/Rhabdoid Tumors].

Atypical teratoid/rhabdoid tumor(AT/RT)is a rare and lethal childhood cancer. Although radiation therapy in children less than three years of age is generally deferred because of its neural toxicity, recent studies have shown that multimodal therapies, including radiation therapy, are effective in pediatric patients with AT/RT less than three years of age. We treated four infant AT/RT patients and investigated the impact of radiation therapy and genetic classification on the prognosis. The mean age at the time of the operation was 9.3 months and all patients were female. All patients underwent surgical resection. Of the four patients, two received combined irradiation and chemotherapy. Specifically, one patient received conformal craniospinal radiation therapy and the other received craniospinal irradiation with proton beams. Immunohistochemical analyses of tumor specimens revealed that the two patients were positive for ASCL1, a regulator of Notch signaling. Patients who received radiation therapy and exhibited ASCL1-positive tumors had a better prognosis. We conclude that radiation therapy may prolong survival in AT/RT patients who are less than 3 years of age. However, further study is required to evaluate long-term functional outcomes.

Atypical teratoid rhabdoid tumor in the first year of life: the Canadian ATRT registry experience and review of the literature.

While 2/3 of patients with ATRT are less than 3 years at diagnosis, the literature suggests younger children present with more aggressive disease and poorer outcome. However, little data exist on characteristics and outcome of patients diagnosed with ATRT in the first year of life. In particular, it is unclear whether they access similar treatments as do older children. We compared the cohort of patients ≤12 months from the Canadian ATRT registry to all cases extracted from the literature reported between 1996 and 2014 to describe their clinical and treatment characteristics, and potential prognostic factors. Twenty-six (33.7%) patients from the Canadian registry were ≤12 months at diagnosis as were 120 cases identified in the literature. Post-operatively, 46% of the registry's patients underwent palliation as opposed to 10.8% in the literature cohort. Palliative patients were significantly younger than those who received active therapy (3.3 vs. 6.6 months). While the use of high-dose chemotherapy (HDC) was relatively similar in both cohorts (42.9 and 35.5% respectively), radiotherapy (RT) use was significantly lower in the Canadian cohort (14.3 vs 44.9%). Children ≤6 months, who received active therapy, had a worst outcome than older ones. Gross total resection, HDC and adjuvant RT were associated with better outcomes. Eighty percent of the tested patients had evidence of germline mutation of INI1. While 1/3 of ATRT occurs within the first year of life, a large proportion only received palliative therapy. Even when actively treated, children ≤6 months fare worse. Some selected patients benefit from HDC.

Assessment of the treatment approach and survival outcomes in a modern cohort of patients with atypical teratoid rhabdoid tumors using the National Cancer Database.

BACKGROUND: Atypical teratoid rhabdoid tumors (ATRTs) are rare brain tumors that occur primarily in children under the age of 3 years. This report evaluates the treatment approach and survival outcomes in a large cohort of patients treated in the United States. METHODS: Using the National Cancer Database, the analysis included all ATRT patients aged 0 to 18 years who were diagnosed between 2004 and 2012 and had complete treatment data. RESULTS: Three hundred sixty-one ATRT patients were evaluated. The 5-year overall survival (OS) rate was 29.9%, and it was significantly lower for children who were less than 3 years old (5-year OS, 27.7%) versus those who were 3 years old or older (5-year OS, 37.5%; P < .001). The best outcome was seen for patients with localized disease who received trimodality therapy (surgery, chemotherapy, and radiation therapy [RT]) with a 5-year OS rate of 46.8%. The utilization of trimodality therapy significantly increased during the study period (27.7% in 2004-2008 vs 45.1% in 2009-2012; P < .01), largely because of the increased use of RT. In a multivariate analysis, treatment that did not utilize trimodality therapy was associated with significantly worse OS (hazard ratio, 2.52; 95% confidence interval (1.82-3.51). Children aged 0 to 2 years were significantly less likely to receive trimodality therapy because of decreased utilization of RT in this age group. CONCLUSIONS: The use of trimodality therapy significantly increased during the study period and was associated with improved outcomes. For patients with localized disease who received trimodality therapy, the OS rate at 5 years approached 50%. However, further research into the optimal management of children less than 3 years old is needed because of their significantly worse OS in comparison with older children. Cancer 2017;123:682-687. © 2016 American Cancer Society.

Inhibition of DNA damage repair by the CDK4/6 inhibitor palbociclib delays irradiated intracranial atypical teratoid rhabdoid tumor and glioblastoma xenograft regrowth.

BACKGROUND: Radiation therapy is the most commonly used postsurgical treatment for primary malignant brain tumors. Consequently, investigating the efficacy of chemotherapeutics combined with radiation for treating malignant brain tumors is of high clinical relevance. In this study, we examined the cyclin-dependent kinase 4/6 inhibitor palbociclib, when used in combination with radiation for treating human atypical teratoid rhabdoid tumor (ATRT) as well as glioblastoma (GBM). METHODS: Evaluation of treatment antitumor activity in vitro was based upon results from cell proliferation assays, clonogenicity assays, flow cytometry, and immunocytochemistry for DNA double-strand break repair. Interpretation of treatment antitumor activity in vivo was based upon bioluminescence imaging, animal subject survival analysis, and staining of tumor sections for markers of proliferation and apoptosis. RESULTS: For each of the retinoblastoma protein (RB)-proficient tumor models examined (2 ATRTs and 2 GBMs), one or more of the combination therapy regimens significantly (P < .05) outperformed both monotherapies with respect to animal subject survival benefit. Among the combination therapy regimens, concurrent palbociclib and radiation treatment and palbociclib treatment following radiation consistently outperformed the sequence in which radiation followed palbociclib treatment. In vitro investigation revealed that the concurrent use of palbociclib with radiation, as well as palbociclib following radiation, inhibited DNA double-strand break repair and promoted increased tumor cell apoptosis. CONCLUSIONS: Our results support further investigation and possible clinical translation of palbociclib as an adjuvant to radiation therapy for patients with malignant brain tumors that retain RB expression.

A novel supine isocentric approach for craniospinal irradiation and its clinical outcome.

OBJECTIVE: To report a novel approach for craniospinal irradiation (CSI) using a supine isocentric technique. METHODS: Patients were treated in the supine position using CT simulation. Half-beam-blocked lateral cranial fields and superior spinal fields have the same isocentre, and their beam divergences match. Tangential irradiation provides a non-divergent junction for the other two full-beam spinal fields. Shielding for cranial fields was generated, and dose distribution was calculated using a three-dimensional planning system. When sacral spinal fields were required, two lateral opposite fields were designed to protect the urogenital organs. All treatment portals were filmed once per week. RESULTS: At a median follow-up of 49.8 months, 5 relapses and no cases of radiation myelitis developed in 26 consecutive patients. In the junctions of the brain-spine or spine-spine field, no failure occurred. Three failures occurred in the primary site alone, two in the spinal axis alone. CONCLUSION: The results of our study have shown that our novel approach for CSI was not associated with increased failures at the field junction and deaths. In addition, no radiation myelitis, pneumonia, severe damage to the heart and gastrointestinal tract, and second cancers occurred in our study. ADVANCES IN KNOWLEDGE: This new approach is an optimal alternative in cancer centre without tomotherapy because of its convenience for immobilization, repeatability, optimal dose distribution and satisfactory clinical outcome.