Long-term outcome of salvage high-dose chemotherapy in patients with germ cell tumor with poor prognostic features

Primary Mediastinal and Testicular Germ Cell Tumors in Adolescents and Adults: A Comparison of Genomic Alterations and Clinical Implications

Simple Summary

The germ cell tumors (GCTs) family is a heterogeneous group of neoplasms that includes tumors affecting testis (TGCTs) and rarer cases occurring in extragonadal sites. Mediastinal germ cell tumors (MGCTs) are more aggressive and have poorer prognosis. Due to their rarity of MGCTs, few molecular and clinical studies are reported. MGCTs share biological similarities with TGCT, and international guidelines recommend use of the same therapies validated for TGCT. However, while high response rate is achieved in TGCT, MGCT tend to be resistant to therapy. This review resumes all molecular findings reported in MGCTs, summarizing molecular characteristics common with TGCT and highlighting the different molecular alterations that characterize mediastinal tumors. A deeper understanding of the MGCT biology will help in clinical management of these patients.

Abstract

Mediastinal germ cell tumors (MGCTs) share histologic, molecular and biomarkers features with testicular GCTs; however, nonseminomatous MGCTs are usually more aggressive and have poorer prognosis than nonseminomatous TGCTs. Most nonseminomatous MGCT cases show early resistance to platinum-based therapies and seldom have been associated with the onset of one or more concomitant somatic malignancies, in particular myeloid neoplasms with recent findings supporting a common, shared genetic precursor with the primary MGCT. Genomic, transcriptomic and epigenetic features of testicular GCTs have been extensively studied, allowing for the understanding of GCT development and transformation of seminomatous and nonseminomatous histologies. However, MGCTs are still lacking proper multi-omics analysis and only few data are reported in the literature. Understanding of the mechanism involved in the development, in the progression and in their higher resistance to common therapies is still poorly understood. With this review, we aim to collect all molecular findings reported in this rare disease, resuming the similarities and disparities with the gonadal counterparts.

Survival Outcomes After High-dose Chemotherapy and Stem Cell Transplantation in the Salvage Setting for Relapsed or Refractory Germ Cell Cancers

BACKGROUND/AIM

High-dose chemotherapy (HDCT) and stem cell transplantation (SCT) have been established as the standard of care in patients with relapsed germ cell tumours (GCTs). We evaluated the safety, efficacy and tolerability of HDCT/ SCT in patients with relapsed GCTs.

PATIENTS AND METHODS

Twenty-eight patients with relapsed GCTs, treated with HDCT, were included in this study. The conditioning regime was carboplatin, etoposide, cyclophosphamide and paclitaxel. Clinical, radiological imaging and tumour markers determined treatment outcomes.

RESULTS

Median age was 35 years (range=21-57 years) with 26 males and 2 females. Median time to first relapse was 6 months. Median time to progression after 2^nd line chemotherapy was 17.3 months. Fourteen patients hadMedian survival was 62 months and 16 patients (57%) are in clinical follow-up with surveillance.

CONCLUSION

In relapsed GCT patients, median survival may exceed 5 years post-HDCT and SCT.

Immunotherapy in Testicular Germ Cell Tumors

Testicular germ cell tumors (TGCTs) are malignancies with very high curative potential even in metastatic settings, mainly due to the introduction of cisplatin in the treatment of this disease. However, in a group of patients with cisplatin-refractory disease or with progressive disease despite high-dose salvage chemotherapy treatment, the prognosis is typically dismal. The triple combination of gemcitabine, oxaliplatin, and paclitaxel (GOP) has reasonable efficacy and is considered to be standard care for this group of patients. It remains to be seen, however, whether refractory TGCTs may represent a potential target for immune checkpoint inhibition. This review will focus on the rationale of the use of immunotherapy for platinum-refractory TGCTs and summarize data reporting experiences with immune checkpoint inhibitor treatment for this malignancy.

Phase II study of avelumab in multiple relapsed/refractory germ cell cancer

Background Germ cell tumors (GCTs) are highly curable diseases; however, not all patients can be cured. Patients in their second relapse have especially poor prognoses. PD-L1 expression is significantly higher in GCTs than in normal testicular tissue, and high PD-L1 expression is associated with a poor prognosis. This study aimed to determine the efficacy and safety of avelumab, a PD-L1 inhibitor, in patients with GCTs. Methods In this phase 2 study, patients with multiple relapsed and/or refractory GCTs were treated with avelumab at a dose of 10 mg/kg administered biweekly until progression or unacceptable toxicity. The primary endpoint was 12-week progression-free survival (PFS). Fifteen evaluable patients had to be enrolled in the first cohort, and if <8 of 15 patients had 12-week PFS, the study was to be terminated. Here, we report the results of the first stage of the trial. Results From November 2017 to January 2018, 8 patients with a median age of 29 years (range, 22 to 52 months) were enrolled. Patients were pretreated with a median of 5 (range, 1 to 6) previous lines of platinum-based therapies; 5 tumors (62.5%) were absolutely refractory to cisplatin, and 5 patients (62.5%) had visceral nonpulmonary metastases. At a median follow-up period of 2.6 months (range, 0.3 to 14.4), all the patients experienced disease progression, and 7 patients (87.5%) died. The twelve-week PFS was 0%, median PFS was 0.9 months (95% CI 0.5-1.9), and median OS was 2.7 months (95% CI 1.0-3.3). Avelumab was well tolerated, and no severe adverse events were observed. Conclusions This study failed to achieve its primary endpoint. Our data suggest a lack of avelumab efficacy in unselected multiple relapsed/refractory GCTs.

Impact of Non-Pulmonary Visceral Metastases in the Prognosis and Practice of Metastatic Testicular Germ Cell Tumors

Non-pulmonary visceral metastases, in bones, brain and liver, represent nearly the 10% of metastatic sites of advanced germ cell tumors and are associated with poor prognosis. This review article summarizes major evidences on the impact of different visceral sites on the prognosis, treatment and clinical outcome of patients with germ cell tumors. The clinic-biological mechanisms by which these metastatic sites are associated with poor clinical outcome remain unclear. The multimodality treatment showed a potential better survival, in particular in patients with relapsed disease. Patients with advanced germ cell tumors with visceral metastases should be referred to centers with high expertise in the clinical management of such disease.

Phase II study of everolimus in refractory testicular germ cell tumors

BACKGROUND

Testicular germ cell tumors (TGCTs) represent a highly curable disease; however, a small proportion of patients develop disease recurrence. Loss of the tumor-suppressor gene phosphatase and tensin homolog marks the transition from intratubular germ cell neoplasia to invasive GCT and is correlated with disease progression. Inactivation of phosphatase and tensin homolog is associated with deregulation of the PI3K/Akt pathway and increased mammalian target of rapamycin signaling. This study aimed to determine the efficacy and toxicity of a mammalian target of rapamycin inhibitor, everolimus, in patients with refractory TGCTs.

METHODS

From December 2011 to February 2015, 15 patients with refractory GCTs were enrolled in the phase II study. All patients were pretreated with at least 2 cisplatin-based therapies; 4 tumors (26.7%) were absolutely refractory to cisplatin and 9 patients (60.0%) had visceral nonpulmonary metastases. Everolimus was administered at a dose of 10mg daily until progression or unacceptable toxicity. The primary end point was the objective response rate, according to Response Evaluation Criteria in Solid Tumors.

RESULTS

No objective response was observed, but 6 patients (40.0%) achieved 12-week progression-free survival. During a median follow-up period of 3.6 months (range: 1-35.1mo), all patients experienced disease progression and 11 patients (80.0%) died. Median progression-free survival was 1.7 months (95% CI: 1.1-4.0mo) and median overall survival was 3.6 months (95% CI: 2.0-11.0mo).

CONCLUSIONS

This study failed to achieve its primary end point and our data suggest limited efficacy of everolimus against unselected heavily pretreated refractory TGCTs.

CONDENSED ABSTRACT

Everolimus showed limited efficacy in unselected heavily pretreated refractory TGCTs. Prolonged disease stabilization could be achieved in selected patients.

Alpha-fetoprotein surge following high-dose chemotherapy in germ cell tumours

In patients with non-seminomatous germ cell tumours (NSGCTs) who receive chemotherapy and have residual disease, a persistently elevated serum marker level after induction chemotherapy indicates active and progressive disease. High-dose chemotherapy (HDCT) is the standard treatment for patients with relapsed NSGCT. We present a case of a patient with residual disease from NSGCT who showed an increase in serum alpha-fetoprotein levels after HDCT, mimicking progression. Resection of the mass did not show viable cells in the tumour specimen, thus suggesting that the elevated level of the marker was expression of hepatic reconstitution after drug-induced liver damage. HDCT is increasingly used in cases of relapsed NSGCT, and the possibility of treatment-induced alpha-fetoprotein elevation must be taken into account in patient management.

Multidisciplinary management of malignant ovarian germ cell tumours

OBJECTIVES

Malignant ovarian germ cell tumours (MOGCT) are rare cancers of young women. Limited prospective trials exist from which evidence-based management can be developed. This review summarizes the available literature concerning MOGT in order to provide the clinician with information relevant to their multidisciplinary management.

METHODS

MEDLINE was searched between 1966 and 2010 for all publications in English where the studied population included women diagnosed with malignant ovarian germ cell tumours.

RESULTS

The majority of patients can be cured with fertility-preserving surgery with or without combination chemotherapy. Long term survival approaches 100% in early stage disease and is approximately 75% in advanced stage disease. Most studies suggest that the treatment has little, if any, effect on future fertility and limited data suggest that there is no adverse effect on the future quality of life.

CONCLUSION

MOGCTs are rare tumours of young women the majority of which can be successfully treated with fertility-preserving surgery with or without chemotherapy with preservation of reproductive function. Minimisation of chemotherapy in good prognostic groups and improved treatment in resistant and relapsed MOGCT are important goals for the future. Further studies are needed to quantify the late adverse effects of treatment in long term survivors.