Treatment strategy for intracranial primary pure germinoma

Whole-exome sequencing has revealed novel genetic characteristics in intracranial germ cell tumours in the Chinese

AIMS

Intracranial germ cell tumour (IGCT) is a type of rare central nervous system tumour that mainly occurs in children and adolescents, with great variation in its incidence rate and molecular characteristics in patients from different populations. The genetic alterations of IGCT in the Chinese population are still unknown.

METHODS AND RESULTS

In this study, 47 patients were enrolled and their tumour specimens were analysed by whole-exome sequencing (WES). We found that KIT was the most significantly mutated gene (15/47, 32%), which mainly occurred in the germinoma group (13/20, 65%), and less frequently in NGGCT (2/27, 7%). Copy number variations (CNVs) of FGF6 and TFE3 only appeared in NGGCT patients (P = 0.003 and 0.032, respectively), while CNVs of CXCR4, RAC2, PDGFA, and FEV only appeared in germinoma patients (P = 0.004 of CXCR4 and P = 0.027 for the last three genes). Compared with a previous Japanese cohort, the somatic mutation rates of RELN and SYNE1 were higher in the Chinese. Prognostic analysis showed that the NF1 mutation was associated with shorter overall survival and progression-free survival in IGCT patients. Clonal evolution analysis revealed an early branched evolutionary pattern in two IGCT patients who underwent changes in the histological subtype or degree of differentiation during disease surveillance.

CONCLUSION

This study indicated that Chinese IGCT patients may have distinct genetic characteristics and identified several possible genetic alterations that have the potential to become prognostic biomarkers of NGGCT patients.

Intracranial Germ Cell Tumors

Intracranial germ cell tumors are rare tumors occurring in adolescents and young adults, which include germinomas and non-germinomatous type germ cell tumors (NGGCT). In the past few decades, cooperative trial groups in Europe and North America have developed successful strategies to improve survival outcomes and decrease treatment-related toxicities. New approaches to establishing diagnosis have deferred the need for radical surgery. The 5-year event-free survival (EFS) is above 90% and even patients who present with metastatic germinoma can still be cured with chemotherapy and craniospinal irradiation. The combination of surgery, chemotherapy, and radiation therapy is tailored to patients based on grouping and staging. For NGGCT, neoadjuvant chemotherapy followed by delayed surgery for residual disease and radiotherapy can yield a 5-year EFS of 70%. Further strategies should focus on reducing long-term complications while preserving high cure rates.

Genomic characterization of intracranial teratomas using whole genome sequencing

Background

Intracranial teratoma is a rare neoplasm of the central nervous system, often classified into mature and immature types and occurs mainly in children and adolescents. To date, there has been no comprehensive genomic characterization analysis of teratoma due to its rarity of the cases.

Methods

Forty-six patients with intracranial teratomas were collected and 22 of them underwent whole-exome sequencing, including 8 mature teratomas and 14 immature teratomas. A comprehensive analysis was performed to analyze somatic mutations, copy number variants (CNVs), mutational signatures, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway in our cohort.

Results

The most common somatic mutated gene in intracranial teratomas was CARD11 (18%) and IRS1 (18%), followed by PSMD11, RELN, RRAS2, SMC1A, SYNE1 and ZFHX3, with mutation rates of 14% for the latter six genes. Copy number variation was dominated by amplification, among which ARAF (50%), ATP2B3 (41%), GATA1 (41%), ATP6AP1 (36%), CCND2 (36%) and ZMYM3 (36%) were the most frequently amplified genes. Copy number deletion of SETDB2 and IL2 only appeared in immature teratoma (43% and 36%, respectively), but not in mature teratoma (p = 0.051 and 0.115, respectively). Prognostic analysis showed that TP53 mutations might be associated with poor prognosis of intracranial teratomas patients.

Conclusions

Our study revealed the genetic characteristics of intracranial teratoma which might be valuable for guiding future targeted therapies.

Long-Term Outcomes and Sequelae Analysis of Intracranial Germinoma: Need to Reduce the Extended-Field Radiotherapy Volume and Dose to Minimize Late Sequelae

PURPOSE

We aimed to refine the radiotherapy (RT) volume and dose for intracranial germinoma considering recurrences and long-term toxicities.

MATERIALS AND METHODS

Total 189 patients with intracranial germinoma were treated with RT alone (n=50) and RT with upfront chemotherapy (CRT) (n=139). All cases were confirmed histologically. RT fields comprised the extended-field and involved-field only for primary site. The extended-field, including craniospinal, whole brain (WB), and whole ventricle (WV) for cranial field, is followed by involved-field boost. The median follow-up duration was 115 months.

RESULTS

The relapses developed in 13 patients (6.9%). For the extended-field, cranial RT dose down to 18 Gy exhibited no cranial recurrence in 34 patients. In CRT, 74 patients (56.5%) showed complete response to chemotherapy and no involved-field recurrence with low-dose RT of 30 Gy. WV RT with chemotherapy for the basal ganglia or thalamus germinoma showed no recurrence. Secondary malignancy developed in 10 patients (5.3%) with a latency of 20 years (range, 4 to 26 years) and caused mortalities in six. WB or craniospinal field rather than WV or involved-field significantly increased the rate of hormone deficiencies, and secondary malignancy. RT dose for extended-field correlated significantly with the rate of hormone deficiencies, secondary malignancy, and neurocognitive dysfunction.

CONCLUSION

De-intensifying extended-field rather than involved-field or total scheme of RT will be critical to decrease the late toxicities. Upfront chemotherapy could be beneficial for the patients with complete response to minimize the RT dose down to 30 Gy. Prospective trials focused on de-intensification of the extended-field RT are warranted.

Historical overview of the Department of Neurosurgery at Yonsei University College of Medicine in the Republic of Korea

Originally founded in 1885, Gwanghyewon later became the Severance Hospital (named after philanthropist Louis Severance, who supported and funded the construction of a modern hospital) and Yonsei University College of Medicine. The Department of Neurosurgery at Severance Hospital was established in 1957, and its residency program began in 1961. Currently, the Department of Neurosurgery has 34 professors and 17 fellows; specialties include vascular, functional, pediatric, tumor, skull base, and spine neurosurgery. With its state-of-the-art neurosurgical facilities and services, the Department of Neurosurgery has developed into a department of excellence within the Yonsei University Health System. In this vignette, the authors present a historic overview of the Department of Neurosurgery.

Suprasellar germinoma with hypopituitarism in an 18-year old man: A case report and review of literature

An 18 year old patient was presented to the ophtalmology outpatient clinic with blurrred vision, headache and fatigue for 6 months. Ophtalmological examination showed loss of visual acuity in the left eye and decreased in the right eye and bilateral optic atrophy. Further physical examination pointed out delayed sexual development. Hypopituitarism was observed in endocrinological examination. Brain magnetic resonance imaging (MRI) demonstrated contrast enhancing mass lesion at suprasellar region with involvement of posterior perimesencephalic cisternal region. The mass resected by craniotomy and pathology showed germinoma. Afterwards he received systemic chemotherapy with bleomisin, etoposide, cisplatin for 4 cycles followed by cranial radiotherapy with 30.6 Gy with a boost to the primary tumor at a dose of 19.8 Gy. On his follow-up MRI, there are no signs of residual tumor nor tumor recurrence. His final examination reveals slightly increased visual acuity in the right eye and he continued to take hydrocortisone and L-thyroxin. After one year follow-up, human chorionic gonadotropin (hCG) alpha treatment was started for sexual development. Here in, we present a case with suprasellar germinoma in the context of the review of the literature.

Intensity-modulated ventricular irradiation for intracranial germ-cell tumors: Survival analysis and impact of salvage re-irradiation

Background and purpose

The roles of surgery, chemotherapy, and parameters of radiation therapy for treating very rare central nervous system germ cell tumors (CNS-GCT) are still under discussion. We aimed to evaluate the survival and recurrence patterns of patients with CNS-GCT treated with chemotherapy followed by whole ventricle irradiation with intensity-modulated radiation therapy.

Materials and methods

We reviewed the clinical outcomes of 20 consecutive patients with CNS-GCT treated with chemotherapy and intensity-modulated radiation therapy from 2004 to 2014 in two partner institutions.

Results

Twenty children with a median age of 12 years were included (16 males). Sixteen tumors were pure germinomas, and 4 were non-germinomatous germ cell tumors (NGGCT). All patients were treated with intensity-modulated radiation therapy guided by daily images, and 70% with volumetric intensity-modulated arc radiotherapy additionally. The median dose for the whole-ventricle was 25.2 Gy (range: 18–30.6 Gy) and 36 Gy (range: 30–54 Gy) for the tumor bed boost. The median post-radiation therapy follow-up was 57.5 months. There were 3 recurrences (2 NGGCT and 1 germinoma that recurred as a NGGCT), with 1 death from the disease and the other 2 cases each successfully rescued with chemotherapy and craniospinal irradiation. The overall survival at 5 years was 95% and disease-free survival was 85%.

Conclusions

The results of this study suggest that the combined use of chemotherapy followed by whole ventricle irradiation with intensity-modulated radiation therapy is effective for CNS-GCTs, especially pure germinomas. Even being rescued with craniospinal irradiation, the NGGCT cases have markedly worse prognoses and should be more rigorously selected for localized treatment.

Upfront chemotherapy followed by response adaptive radiotherapy for intracranial germinoma: Prospective multicenter cohort study

PURPOSE

To assess the efficacy of upfront chemotherapy followed by response-adapted reduced-dose/reduced-volume radiotherapy (RT) for intracranial germinoma.

MATERIALS AND METHODS

Ninety-one patients from five institutions were registered in the KSPNO G051/G081 Protocol. Germinomas were classified as solitary or multiple/disseminated diseases, and upfront chemotherapy was administered. For all patients with multiple or disseminated disease, and patients with partial response after chemotherapy, 19.5-24 Gy of craniospinal irradiation plus 10.8-19.8 Gy of tumor bed boost were planned. For patients with complete response (CR), reduced-dose RT (30.6 Gy) was planned, along with a reduced field for solitary lesions.

RESULTS

The median patient age was 14 (range, 3-30) years. Sixty-five patients (71.4%) had a solitary lesion. The median follow-up duration was 67.9 (range, 6.6-119.3) months. Recurrence was not observed in 32 patients in the protocol compliant group. Four patients (4.4%) in the protocol non-compliant group experienced relapse after CR and one patient died of the disease. The 5-year and 7-year overall survival rates were 98.8% and 98.8%, while the corresponding event-free survival rates were 96.6% and 93.8%, respectively. All three patients with basal ganglia germinomas who were treated with local RT experienced recurrence outside the RT field. Among the 23 patients with pineal or suprasellar lesions who received whole-ventricle RT, there was no recurrence.

CONCLUSIONS

Currently used upfront chemotherapy followed by reduced-dose, reduced-volume RT appears acceptable, when whole-ventricle RT for pineal or suprasellar tumors and, at minimum, whole-brain RT for basal ganglia/thalamus lesions are applied.

Treatment outcomes of intracranial germinoma: a retrospective analysis of 170 patients from a single institution

PURPOSE

To perform a retrospective analysis of patients with intracranial germinoma treated in our department to evaluate treatment outcomes and determine optimal treatment strategies.

METHODS

We reviewed the treatment outcomes of 170 patients with intracranial germinoma who were treated in our department from January 1996 to January 2017. The median patient age was 15 years old. Among the patients, 56 (33%) were pathologically diagnosed, and 114 (67%) were diagnosed clinically. Various radiation fields and doses were used. Cerebrospinal fluid (CSF) and serum beta-human chorionic gonadotropin (β-HCG) levels were examined before treatment in 114 patients. Endocrinological evaluation was performed in 141 patients before and after treatment. A total of 38 patients received chemotherapy prior to radiotherapy (RT). The median follow-up time was 64.5 months (range 4-260.5 months).

RESULTS

The 5- and 10-year overall survival (OS) rates were 94.5% and 91.3%, respectively. The relapse-free survival (RFS) rates at 5- and 10-years were 91.9% and 78.1%, respectively. Relapses occurred in 18 patients within 6 months-10 years. The spinal cord metastasis rate was 3.4% in patients with a localized lesion who did not receive spinal cord irradiation and 16.7% in patients with bifocal disease who were treated using whole ventricular irradiation (WVI) or whole brain radiotherapy (WBRT). Treatment failure did not occur in patients receiving chemoradiotherapy or in patients receiving three-dimensional conformal radiation therapy (3D-CRT)/intensity-modulated radiation therapy (IMRT). The RFS rate did not have a statistically significant correlation with the CSF/serum β-HCG level. After RT, 19.1% of the patients developed newly impaired pituitary function and required hormone replacement therapy.

CONCLUSIONS

WVI or WBRT+ primary boost (PB) is a sufficient irradiation field for localized intracranial germinoma, while patients with bifocal disease should undergo craniospinal irradiation (CSI), especially when treated with RT alone. CSF β-HCG is not a prognostic marker for intracranial germinomas. The treatment results of chemotherapy followed by reduced-dose RT are comparable to those of RT alone. IMRT is recommended for intracranial germinoma to improve the target volume accuracy and decrease the complications of RT.

Suprasellar Germinomas: 2 Case Reports and Literature Review

BACKGROUND

Germinomas are rare malignant central nervous system tumors, a type of germ cell tumor, according to the 2016 World Health Organization Classification of Brain Tumors. Most of these tumors develop along the midline, most often from the pineal gland, followed by tumors arising in the suprasellar cisterns. Suprasellar germinomas commonly manifest with diabetes insipidus, visual impairment, and hypothalamic-pituitary failure. We present a literature review from the PubMed database and report 2 cases of suprasellar germinomas.

CASE DESCRIPTION

Both pediatric patients presented with progressive visual loss; one did not show endocrinologic impairment, and the other presented with hypothyroidism, diabetes insipidus, and generalized edema. Magnetic resonance imaging showed expansive suprasellar masses in both cases, confirmed as germinomas at histopathologic examination. The patients were treated with the same surgical approach, although their outcomes were different because of endocrinologic and post surgical complications.

CONCLUSIONS

Suprasellar germinomas are highly curable lesions when diagnosed early. The treatment remains controversial and should be individualized, but the association of chemotherapy and radiotherapy allows reduce adverse effects and shows great results.

Primary Germinoma Originating from the Insular Lobe: A Case Report and Review of the Literature

BACKGROUND

Primary intracranial germinomas occurring in the cerebral hemisphere are extremely rare, with only a few reported cases in the literature. We describe an unusual case of a primary germinoma that developed in the insular lobe, with little involvement in the basal frontal lobe.

CASE DESCRIPTION

A 19-year-old man presented with headache and vomiting. Magnetic resonance imaging showed a solitary, ring-like enhanced lesion in the left hemisphere, and a preliminary diagnosis of glioma was made. Surgery was performed, and the diagnosis of germinoma was made based on the histopathologic results.

CONCLUSIONS

The causes of ectopic germinomas of the midline structures of the brain are still unclear, but the theory of misplacement may partially clarify this phenomenon. Reflecting a lack of definitive management guidelines for atypical germinoma, the present patient was treated with focal radiotherapy around the lesion after surgery and achieved remission by 34 months postoperatively.

Differential dosimetric benefit of proton beam therapy over intensity modulated radiotherapy for a variety of targets in patients with intracranial germ cell tumors

Background

We performed dosimetric comparisons between proton beam therapy and intensity modulated radiotherapy (IMRT) of intracranial germ cell tumors (ICGCTs) arising in various locations of the brain.

Materials

IMRT, passively scattered proton therapy (PSPT), and spot scanning proton therapy (SSPT) plans were performed for four different target volumes: the whole ventricle (WV), pineal gland (PG), suprasellar (SS), and basal ganglia (BG). Five consecutive clinical cases were selected from the patients treated between 2011 and 2014 for each target volume. Total 20 cases from the 17 patients were included in the analyses with three overlap cases which were used in plan comparison both for the whole ventricle and boost targets. The conformity index, homogeneity index, gradient index, plan quality index (PQI), and doses applied to the normal substructures of the brain were calculated for each treatment plan.

Results

The PQI was significantly superior for PSPT and SSPT than IMRT for ICGCTs in all locations (median; WV: 2.89 and 2.37 vs 4.06, PG: 3.38 and 2.70 vs 4.39, SS: 3.92 and 2.49 vs 4.46, BG: 3.01 and 2.49 vs 4.45). PSPT and SSPT significantly reduced the mean dose, and the 10 and 15 Gy dose volumes applied to the normal brain compared with IMRT (p ≤ 0.05). PSPT and SSPT saved significantly greater volumes of the temporal lobes and hippocampi (p < 0.05) in the SS and PG targets than IMRT. For tumors arising in the BG, PSPT and SSPT also saved greater volumes of the contralateral temporal lobes.

Conclusions

PSPT and SSPT provide superior target volume coverage and saved more normal tissue compared with IMRT for ICGCTs in various locations. Future studies should assess whether the extent of normal tissue saved has clinical benefits in children with ICGCTs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0441-5) contains supplementary material, which is available to authorized users.

Understanding the Treatment Strategies of Intracranial Germ Cell Tumors: Focusing on Radiotherapy

Intracranial germ cell tumors (ICGCT) occur in 2-11% of children with brain tumors between 0-19 years of age. For treatment of germinoma, relatively low radiation doses with or without chemotherapy show excellent 10 year survival rate of 80-100%. Past studies showed that neoadjuvant chemotherapy combined with focal radiotherapy resulted in unacceptably high rates of periventricular tumor recurrence. The use of generous radiation volume which covers the whole ventricular space with later boost treatment to primary site is considered as standard treatment of intracranial germinomas. For non-germinomatous germ cell tumors (NGGCT), 10-year overall survival rate is still much inferior than that of intracranial germinoma despite intensive chemotherapy and high-dose radiotherapy. Craniospinal radiotherapy combined with cisplatin-based chemotherapy provides the best treatment outcome for NGGCT; 60-70% of overall survival rate. There is a debate on the surgical role whether surgery can contribute to improved treatment outcome of NGGCT when added to combined chemoradiotherapy. Because higher dose of radiotherapy is required for treatment of NGGCT than for germinoma, it is tested whether whole ventricular irradiation can replace craniospinal irradiation in intermediate risk group of NGGCT to minimize radiation-related late toxicity in the recent studies. To minimize the treatment-related neural deficit and late sequelae while maintaining long-term survival rate of ICGCT patients, optimized administration of chemotherapy and radiotherapy should be selected. Use of technically upgraded radiotherapy modalities such as intensity-modulated radiotherapy or proton beam therapy is expected to bring an improved neurocognitive outcome with longitudinal assessment of the patients.