Mediastinal Germ Cell Tumors in Pediatric Patients: A Report From the Italian Association of Pediatric Hematology and Oncology

Mediastinal Germ-cell Tumors Relapse in a Male With Klinefelter Syndrome. Is Longer Surveillance Needed?

Germ cell tumors (GCTs) are a heterogeneous group of pediatric cancers. In up to one-third of male patients, a primary mediastinal location is associated with the presence of Klinefelter syndrome (KS). We describe a case of mediastinal GCT in a patient, with unacknowledged KS, that presented a relapse 7 years from diagnosis, that is, 2 years after the end of the follow-up program usually recommended for patients with GCT. There are no recommendations for screening for KS in patients with mediastinal GCT and there are no specific guidelines for surveillance of GCT in KS patients. Our experience suggests that KS should be suspected in patients with mediastinal GCT, and a longer follow-up plan should be implemented when GCT occurs in patients with KS.

Clinical Features and Survival Outcomes in Children and Adolescents With Malignant Mediastinal Germ Cell Tumors Based on Surveillance, Epidemiology, and End Results Database Analysis

INTRODUCTION

The purpose of this study was to perform a population-based investigation to assess the disease characteristics and prognosis of children and adolescents with malignant mediastinal germ cell tumors (MMGCT).

METHODS

Data on the demographics, treatment, and survival outcomes of children and adolescents with MMGCT from January 1, 2000 to December 31, 2018 were obtained. To compare survival curves, the log-rank test was employed. The generation of survival curves based on different parameters was done using Kaplan-Meier estimations. Cox proportional hazards regression was performed to determine the variables linked to disease-specific survival.

RESULTS

The selection criteria were met by 152 MMGCT patients, 130 of whom were male. Fifty three cases of mixed germ cell tumors (GCTs), 41 cases of malignant teratomas, 26 cases of yolk sac tumors, 14 cases of seminoma, 13 cases of choriocarcinomas, and five cases of embryonal carcinoma were reported. Overall survival at 3 and 5 y for all patients was 63.1% and 61.2%, respectively. Malignant teratoma, yolk sac tumors, and mixed GCTs in children and adolescents had comparable survival rates, while those with choriocarcinoma and embryonal carcinoma showed the worst prognosis. Embryonal carcinoma, malignant teratoma, mixed GCTs, and choriocarcinoma were found as risk factors by multivariate Cox proportional hazards analysis. In contrast, surgery and younger age were protective factors. However, chemotherapy alone showed no survival benefits.

CONCLUSIONS

Our population-based evidence showed that MMGCT had worse prognosis in older children and adolescents. Choriocarcinomas and embryonal carcinomas had the worst prognosis. Surgery can prolong survival time. Chemotherapy and radiotherapy were not associated with improved prognosis.

Surgical treatment confers prognostic significance in pediatric malignant mediastinal germ cell tumors

BACKGROUND

Primary malignant mediastinal germ cell tumors (GCTs) are rare pediatric tumors that have a poorer prognosis compared to GCTs occurring elsewhere in the body. The current study aimed to assess the prognostic factors and treatment outcomes of children with primary malignant mediastinal GCT in Taiwan.

METHODS

The authors retrospectively reviewed children 0-18 years old who were newly diagnosed with primary malignant mediastinal GCT between January 1, 2005 and December 31, 2019 and were registered in the Taiwan Pediatric Oncology Group patient registry. The impact of presenting characteristics, including sex, age, tumor stage, histology subtype, surgical treatment, and chemotherapy regimens of the patients were analyzed.

RESULTS

This study enrolled 52 children with malignant mediastinal GCT who had a median age of 16.0 (range, 6.0-17.9) years at diagnosis. The most common histological subtypes were mixed GCTs (n = 20) and yolk sac tumors (n = 15). Advanced disease stage and choriocarcinoma histology subtype were associated inferior outcomes. Children who received surgical treatment exhibited better outcomes compared to those who did not (5-year overall survival, 78% vs. 7%, p < .001). After comparing patients who received first-line cisplatin- and carboplatin-based chemotherapy, no difference in treatment outcomes was observed. Multivariate analysis showed that surgical management was the only independent predictor for superior OS.

CONCLUSIONS

Surgical treatment is recommended for mediastinal GCT. Cisplatin-based chemotherapy was not superior to carboplatin-based chemotherapy as first-line treatment and may be avoided due to toxicity concerns.

Peri-treatment adverse events of primary mediastinal non-seminomatous germ cell tumors

Primary mediastinal non-seminomatous germ cell tumors (PMNSGCT) are rare but life-threatening thoracic cancers. We report our experience from eight patients with peri-treatment adverse events. By analyzing changes in tumor extent, serum tumor markers, and pathologies between diagnosis and transfer, those events could be attributed to postbiopsy respiratory insufficiency, growing teratoma syndrome, secondary histiocytic malignancy, and PMNSGCT progression. Subjecting patients to respiratory therapy, conventional or high-dose chemotherapy, and surgery controlled the disease, with five of the eight patients surviving disease free. These outcomes indicate that integrated appropriate and timely approaches are important in tackling peri-treatment adverse events.

Salvage treatment for children with relapsed/refractory germ cell tumors: The Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) experience

BACKGROUND

Malignant germ cell tumors (GCTs) are a heterogeneous group of rare neoplasms in children. Optimal outcome is achieved with multimodal therapies for patients with both localized and advanced disease, especially after the introduction of platinum-based chemotherapy regimens. In this respect, data on salvage treatment for children with relapsed or platinum-refractory disease are still limited.

METHODS

Retrospective analysis of data regarding patients affected by malignant GCTs with platinum-refractory or relapsed disease after first-line treatment according to AIEOP TCGM 2004 protocol was conducted.

RESULTS

Twenty-one patients, 15 females and 6 males, were considered for the analysis. All 21 patients received second-line conventional chemotherapy (SLCT), two of these immediately after surgery for local relapse removal. Two patients showed a progression of disease during SLCT and died of disease shortly thereafter, whereas 19 patients were in partial remission (PR) or complete remission (CR) after SLCT. Treatment after SLCT consisted in surgery on residual tumor mass (9/19) followed by high dose of chemotherapy (HDCT) with autologous hematopoietic stem cell support (16/19). The overall survival (OS) and event-free survival of the whole populations are 71% and 66.6%, respectively. Platinum-refractory patients OS is 54.5% compared with 91.5% of the relapsed group. There were no treatment-related deaths.

CONCLUSION

SLCT followed or not by HDCT is an effective salvage treatment for children with relapsed/refractory GCTs. However, the role of HDCT following SLCT needs to be further investigated, especially regarding the identification of specific patient subgroups, which can benefit from this more intensive treatment.

Management and Long-term Outcomes of Giant Mediastinal Germ Cell Tumors in Children

Purpose: The purpose of the study is to evaluate the outcome of children with giant mediastinal germ cell tumors (GCTs). Materials and Methods: A retrospective study of children diagnosed with GCTs treated at our hospital from 1998 to 2014 was performed. They were evaluated for their tumor size, malignancy, treatment, complications, and outcome. Results: Twelve giant mediastinal GCT patients were included in the study. Age ranged from 7 to 144 months (median 12 months) and all except one were males. The average tumor size was 10.4 cm (range 6 cm × 5 cm–16 cm × 13 cm) and in four patients, they were large enough to occupy nearly the entire hemithorax. Nine children had benign tumors, and these were resected upfront. The remaining three cases with malignant disease received neoadjuvant chemotherapy. No significant reduction in size was noticed in these patients, but alpha-fetoprotein levels decreased in all the three, and they were later resected. Eight (67%) were resected through posterolateral thoracotomy and 4 (33%) through median sternotomy approach. One patient had a dumbbell-shaped thoracoabdominal tumor extending through a Bochdalek hernia. He required additional laparotomy as well as diaphragmatic repair. There were no postoperative complications. The malignant GCTs received total four courses of PEB. All patients were alive and asymptomatic at a mean follow-up of 55.4 months (range 10–146 months). Conclusions: Mediastinal GCTs have bimodal age distribution and show male preponderance. Malignant mediastinal GCTs responded well to neoadjuvant chemotherapy through a reduction in size was not noticed. Complete excision often in coordination with cardiothoracic-vascular surgeons can lead to long-term symptom-free survival even in giant tumors.

Pediatric mediastinal germ cell tumors

Mediastinal germ cell tumors (GCTs) are a rare and heterogeneous group of neoplasms. Although histologically resembling their gonadal counterparts, they differ considerably in their clinical characteristics, biological behavior and prognostic outcome. The rarity of mediastinal GCTs has hindered their meaningful analysis, with most studies and clinical trials including them along with other extragonadal GCTs, which has led to a lack of consensus on optimal treatment strategies, and a lull in improvement in patient outcomes. Diagnosis of mediastinal GCT requires a multipronged approach, and encompasses multidisciplinary treatment including chemotherapy followed by surgery, with or without radiotherapy. In view of sustained response rates to current management protocols, the focus needs to be shifted to identifying patients in whom treatment regimens can be downscaled with the aim of decreasing long term morbidity and improving quality of life in low risk patient groups, while improving survival rates in poor risk patient subsets. In this scenario, better understanding of the molecular pathogenesis of these tumors may lead to identification of novel biomarkers and therapeutic targets, as well as improved disease segmentation and risk stratification, thus helping to avoid the toxicity and morbidity associated with current one-fits-all treatment strategies. Multi-institutional collaborations across continents are necessary to generate meaningful data, and are the face of future developments in this arena.

Tumor-infiltrating T cells and PD-L1 expression in childhood malignant extracranial germ-cell tumors

Although pediatric malignant extracranial germ-cell tumors (meGCTs) are among the most chemosensitive solid tumors, a group of patients relapse and die of disease. To identify new markers predicting clinical outcome, we examined the prognostic relevance of tumor-infiltrating T lymphocytes (TILs) and the expression of PD-1 and PD-L1 in a cohort of pediatric meGCTs by in situ immunohistochemistry. MeGCTs were variously infiltrated by T cell-subtypes according to the tumor subtype, tumor location and age at diagnosis. We distinguished three different phenotypes: i) tumors not infiltrated by T cells (immature teratomas and half of the yolk sac tumors), ii) tumors highly infiltrated by CD8⁺ T cells expressing PD-1, which identifies activated tumor-reactive T cells (seminomas and dysgerminomas), iii) tumors highly infiltrated by CD8⁺ T cells within an immunosuppressive tumor microenvironment characterized by CD4⁺FOXP3⁺ Treg cells and PD-L1-expressing tumor cells (embryonal carcinomas, choriocarcinomas and the remaining yolk sac tumors). Tumor subtypes belonging mixed meGCTs were variously infiltrated, suggesting the coexistence of multiple immune microenvironments either facilitating or precluding the entry of T cells. These findings support the hypothesis that TILs influence the development of meGCTs and might be of clinical relevance to improve risk stratification and the treatment of pediatric patients.

Primary mediastinal and retroperitoneal malignant germ cell tumors in children and adolescents: Results of the TGM95 trial, a study of the French Society of Pediatric Oncology (Société Française des Cancers de l'Enfant)

PURPOSE

To examine the clinical presentation, treatment and results in children and adolescents with primary mediastinal (PM) and retroperitoneal (RP) germ cell tumors (GCTs).

METHODS

The TGM95 trial for malignant GCTs was conducted in France between 1995 and 2005 to evaluate a strategy adapted to prognostic factors with cisplatin-based chemotherapy and surgical management. We reviewed patients with TGCTs at PM and RP sites.

RESULTS

Among 239 patients, there were 16 patients with PM and 5 with RP tumors, which represent 9% of all patients, highlighting the rarity of these extragonadal locations. A bimodal demographic distribution was observed (11/21 patients <5 years old and 7/21 patients >12 years old). A majority of patients presented with bulky tumors that required urgent care with neoadjuvant chemotherapy. In all patients, elevation of alpha-fetoprotein indicated a yolk sac tumor component. Human chorionic gonadotrophin was elevated in five patients (four adolescents), suggesting a choriocarcinoma or seminoma component. The diagnosis was based on elevation of these tumor markers in addition to imaging. Chemosensitivity was observed for a majority of patients. An aggressive surgical approach allowed a microscopic complete resection in 12/15 patients with PM tumors and 4/5 with RP tumors. Overall, 14/16 and 4/5 patients survived, respectively. Three adolescents died of tumor progression.

CONCLUSION

In children with mediastinal or RP GCTs, the prognosis is favorable when a strategy of delayed aggressive surgery is performed after cisplatin-based chemotherapy. Younger patients have a better prognosis. Relapses were observed only in adolescents and could not be cured.

Role of post-chemotherapy radiation in the management of children and adolescents with primary advanced malignant mediastinal germ cell tumors

OBJECTIVE

Primary malignant mediastinal germ cell tumors (MMGCTs) are rare in children and adolescents and have a poorer prognosis than their gonadal counterparts. We report a single institutional experience of a 10-year period of primary advanced MMGCTs treated with chemotherapy, followed by radiotherapy in those who had residual mass.

METHODS

Children and adolescents with primary advanced MMGCTs between 2005 and 2014 were identified from the Cancer Center, Sun Yat-Sen University. Medical records were reviewed for clinicopathological characteristics, treatments, and outcomes.

RESULTS

Twenty-four children and adolescents with either stage III or IV primary advanced MMGCTs met the inclusion criteria. There were 23 males and one female with a median age of 16 (range 10-18). Seven cases were seminomas (29.2%); four (16.7%) yolk sac tumors (YST); three (12.5%) choriocarcinomas; and ten (41.6%) nonteratomatous combined germ cell tumors (CGCTs). All patients were treated with first-line cisplatin-based chemotherapy regimens (PEB: 19, VIP: 5). Thirteen (54.2%) and Twelve (50%) patients received surgery and radiotherapy, respectively. With a median follow-up of 46.2 months (range 9.6-124.8 months), a total of five (20%) patients died of disease progression; the five-year overall survival (OS) and disease-free survival (DFS) rates were 82.3% and 64.9%, respectively.-Seven patients with seminoma GCTs received post-chemotherapy irradiation were alive with sustained CR (5-year OS and DFS, 100%, respectively). Five patients with NSGCTs were administered irradiation and one relapsed 35 months later and died of metastasis (5-year OS, 100%; 5-year DFS 66.7%). Univariate analysis identified histology and stage were prognostic factors.

CONCLUSION

Multimodality treatment approach of chemotherapy followed by radiation consolidation ensured long-term survival in primary advanced MMGCTs. Further research is warranted to improve the prognosis of children with primary advanced MMGCTs.

Gonadal germ cell tumors in children: A retrospective review of a 10-year single-center experience

BACKGROUND

The true incidence of gonadal germ cell tumors (GCTs) in children is unknown. Few studies have been published concerning about pediatric gonadal GCTs. The aim of this study is to review and analyze clinical data on the diagnosis and management of gonadal GCTs in children.

METHODS

Between 2005 and 2015, 127 pediatric patients (<14 years old) with gonadal GCTs admitted to our institute were reviewed. Clinical features, imaging and laboratory studies, surgical approaches, as well as pathological diagnoses were recorded.

RESULTS

The series comprised 53 males with testicular GCTs and 74 females with ovarian GCTs. Their median age was 5.8 years old. Palpable mass was the main clinical manifestation of testicular GCTs, while abdominal pain and abdominal distention were the most frequent presenting symptoms of ovarian GCTs. Both computed tomography and magnetic resonance imaging showed a high diagnostic yield. AFP levels were elevated in most malignant GCTs, markedly elevated in yolk sac tumors. All patients were treated surgically. Mature teratoma was the most common type of benign GCTs, while yolk sac tumor was the most common type of malignant GCTs.

CONCLUSION

Gonadal GCTs in children have various of pathological types, as well as clinical manifestations. Imaging and laboratory data could be useful for differentiation of malignant from benign tumors. Final diagnosis depends on pathology. Surgical excision of the gonadal GCTs is the prior option.