Dose-dense chemotherapy for untreated poor-prognosis and relapsed germ-cell tumours: an 18-year experience with GAMEC chemotherapy

Standard versus high-dose chemotherapy in mediastinal germ cell tumors: a narrative review

OBJECTIVE

The aim of this review is to analyze feasibility and toxicities of high-dose chemotherapy (HDCT) in comparison to standard dose chemotherapy (SDCT) in patients affected by mediastinal germ cell tumors (MGCTs), discussing factors that may affect therapeutic choices, such as: management of residual disease, early response predictors for chemotherapeutic efficacy and determinants of chemotherapeutic resistance. In this review, we discuss the main clinical experiences with HDCT and SDCT in germ cell tumor (GCT) patients specifically in those affected by MGCT.

BACKGROUND

MGCTs represent a very small subset characterized by a poor prognosis, despite improvements in their clinical management and in understanding their biology. From early 1970s, HDCT has become an alternative to SDCT for both first-line and salvage therapeutic settings in advanced GCT patients. Several HDCT schedules-either cisplatin or carboplatin-based-have been tested so far, both in clinical randomized trial and in single-center experiences, with divergent results in terms of clinical outcomes and tolerability. Moreover, the majority of these studies included, but were not exclusively designed for, advanced MGCT patients, making difficult to infer data for this specific subset.

METHODS

an extended review of literature through PubMed was conducted using the keywords "mediastinal germinal cell tumors", "standard dose chemotherapy" and "high dose chemotherapy".

CONCLUSIONS

HDCT regimens could not be considered to date a standard option as first-line therapy in advanced MGCT patients, whilst they could be an alternative to SDCT regimens in relapsed tumors after proper patient selection.

ATR and CDK4/6 inhibition target the growth of methotrexate-resistant choriocarcinoma

Low-risk gestational trophoblastic neoplasia including choriocarcinoma is often effectively treated with Methotrexate (MTX) as a first line therapy. However, MTX resistance (MTX-R) occurs in at least ≈33% of cases. This can sometimes be salvaged with actinomycin-D but often requires more toxic combination chemotherapy. Moreover, additional therapy may be needed and, for high-risk patients, 5% still die from the multidrug-resistant disease. Consequently, new treatments that are less toxic and could reverse MTX-R are needed. Here, we compared the proteome/phosphoproteome of MTX-resistant and sensitive choriocarcinoma cells using quantitative mass-spectrometry to identify therapeutically actionable molecular changes associated with MTX-R. Bioinformatics analysis of the proteomic data identified cell cycle and DNA damage repair as major pathways associated with MTX-R. MTX-R choriocarcinoma cells undergo cell cycle delay in G1 phase that enables them to repair DNA damage more efficiently through non-homologous end joining in an ATR-dependent manner. Increased expression of cyclin-dependent kinase 4 (CDK4) and loss of p16^Ink4a in resistant cells suggested that CDK4 inhibition may be a strategy to treat MTX-R choriocarcinoma. Indeed, inhibition of CDK4/6 using genetic silencing or the clinically relevant inhibitor, Palbociclib, induced growth inhibition both in vitro and in an orthotopic in vivo mouse model. Finally, targeting the ATR pathway, genetically or pharmacologically, re-sensitised resistant cells to MTX in vitro and potently prevented the growth of MTX-R tumours in vivo. In short, we identified two novel therapeutic strategies to tackle MTX-R choriocarcinoma that could rapidly be translated into the clinic.

Clinicopathological Features and Prognosis of Primary Mediastinal Malignant Germ Cell Tumors: A Retrospective Single-Institution Analysis

Background

Given the lack of evidence-supported guidance for therapeutic recommendations of primary mediastinal malignant germ cell tumors (PMMGCTs), our study aimed to investigate the clinicopathological features, treatment strategies, and prognostic factors of PMMGCTs.

Methods

We carried out a consecutive retrospective evaluation on a series of patients diagnosed with PMMGCTs in Peking Union Medical College Hospital from January 2000 to August 2020.

Results

A total of 58 patients were eligible, consisting of 51 males and seven females. There were 15 patients with seminomas, 39 with nonseminomatous germ cell tumors (NSGCTs), and four with mixed germ cell tumors (GCTs). The 5-year overall survival was 45%, with a median survival time of 32.37 months. Except for the lost follow-up of seven patients, a univariate analysis of overall survival on the remaining patients showed significant differences in pathological type (mixed GCTs were regarded as NSGCTs) (p=0.036), tumor size (>11cm) (p=0.006), and other sites metastases (OSM) (p=0.001), respectively. Multivariate Cox regression analysis revealed that OSM and surgical resection were independently associated with overall survival in all kinds of PMMGCTs.

Conclusion

OSM was an independent risk factor for patients with PMMGCTs. Surgery was proved to contribute to long-term survival. More in-depth clinical evidence is urgently needed to guide the treatment of PMMGCTs.

The impact of a supranetwork multidisciplinary team (SMDT) on decision-making in testicular cancers: a 10-year overview of the Anglian Germ Cell Cancer Collaborative Group (AGCCCG)

BACKGROUND

The germ cell supranetwork multidisciplinary team (SMDT) for the Anglian Network covers a population of 7.5 million.

METHODS

We reviewed 10 years of SMDT discussion and categorised them into five domains ((1) overall outcome, (2) chemotherapy regimens-untreated disease and salvage therapy, (3) radiology, (4) pathology and (5) complex cases) to assess the impact of the SMDT.

RESULTS

A total of 2892 new cases were reviewed. In the first 5 years, patients with good prognosis disease had poorer survival in low-volume vs high-volume centres (87.8 vs 95.3, p = 0.02), but the difference was no longer significant in the last 5 years (93.3 vs 95.1, p = 0.30). Radiology review of 3206 scans led to rejection of the diagnosis of progression in 26 cases and a further 10 cases were down-staged. There were 790 pathology reviews by two specialised uropathologists, which lead to changes in 75 cases. 18F-fluorodeoxyglucose (18FDG) PET-CT was undertaken during this time period but did not help to predict who would have viable cancer. A total of 26 patients with significant mental health issues who were unable to give informed consent were discussed.

CONCLUSION

SMDT working has led to an improvement in outcomes and refining of treatment in patients with germ cell tumours.