Nomograms for Predicting Prognosis of Primary Mediastinal Seminoma: A Population-Based Study

Objectives

Primary mediastinal seminoma (PMS) was an uncommon carcinoma, and the appropriate treatment remained controversial due to the low incidence. We aimed to investigate the demographics and tumor biological characteristics to determine the potential effective treatment and predict the prognosis.

Methods

Patients diagnosed with PMS were selected between 1975 and 2016 from Surveillance, Epidemiology, and End Results (SEER) database. Kaplan–Meier analysis and Cox proportional hazard model were conducted to determine the prognostic factors, and nomograms were employed to visually predict the prognosis. Concordance index (C-index), calibration curve, and receiver operating characteristic (ROC) curve were conducted to validate the prediction model.

Results

A total of 476 patients were included with a median age of 31 years (range, 2–76 years), and a median size of the tumor was 11.6 cm (range, 0.2–24.0 cm). The 5- and 10-year overall survival (OS) rates were 70.4% and 68.4%, respectively. Age, the extent of the primary site, metastatic status, and surgery performance were independent prognostic factors. Not received surgery was considered a poor prognostic factor for OS (HR, 1.86; 95% CI, 1.13–3.03; P=0.013). The C-index was 0.733 (95% CI, 0.685–0.781) and 0.819 (95% CI, 0.737–0.901) for internal and external validation for predicting OS, respectively. The area under the ROC curve (AUC) was 0.743 (95% CI, 0.681–0.804) for predicting OS (sensitivity, 0.532; specificity, 0.887) in the training cohort.

Conclusions

The nomogram could efficiently predict the survival of patients with PMS. Surgery was the potential effective treatment, and chemotherapy was strongly recommended for patients over 40 years.

Melphalan, Etoposide, and Carboplatin Megatherapy with Autologous Stem Cell Transplantation in Children with Relapsing or Therapy-Resistant Extracranial Germ-Cell Tumors-A Retrospective Analysis

Simple Summary

Germ cell tumors (GCTs) are malignancies derived from germ cells that originate in gonads or extragonadal localizations. They are considered highly curable in both children and adults even if distant metastases are present, but therapy-resistant or relapsing patients have a worse prognosis. The aim of our retrospective study was to analyze the outcome of 18 children with GCT treated with melphalan–etoposide–carboplatin high-dose chemotherapy and autologous stem cell transplantation. To date, this is one of the largest reported pediatric cohorts of GCT patients treated with megatherapy. We observed high survival rates—a five-year overall survival of 76%, and event-free survival of 70.8% without therapy-associated mortality. We concluded that this megatherapy protocol is feasible in heavily pretreated children, but the issue of precise indications for high dose chemotherapy (HDCT) is evident and must be answered in a well-designed controlled study to avoid unnecessary overtreatment.

Abstract

Pediatric germ cell tumors (GCTs) are a group of chemosensitive malignancies with a 90% curability rate. We report a series of children with relapsing or therapy-resistant GCT treated with melphalan–etoposide–carboplatin high-dose chemotherapy (HDCT) and autologous stem cell transplantation. This consisted of 18 children, either with GCTs after relapse (nine patients) or with an unsatisfactory response to first-line chemotherapy (nine patients), who underwent HDCT. The HDCT regimens MEC1 (carboplatin 1500 mg/m², etoposide 1800 mg/m², and melphalan 140 mg/m²) and MEC2 (carboplatin 800 mg/m², etoposide 800 mg/m², and melphalan 140 mg/m²) were each used in nine patients. The median observation time was 81 months, the 5-year overall survival (OS) was 76%, and the event-free survival (EFS) was 70.8%. Non-relapse mortality was 0%, and four patients died after HDCT due to progression of the malignancy. No difference in OS or EFS was noted between the MEC1 and MEC2 protocols. The 5-year OS and 5-year EFS were higher in children treated with autologous stem cell transplantation before the age of four years. The presence of metastatic disease or time of HDCT consolidation during first/subsequent line chemotherapy did not affect patient survival. The melphalan–etoposide–carboplatin protocol is feasible in pediatric GCT, but is associated with potentially life-threatening complications. In conclusion, the use of HDCT must be examined in well-designed clinical trials, and the identification of patients who can benefit from this approach is critical to avoid overtreatment.

Conventional-Dose versus High-Dose Chemotherapy for Relapsed Germ Cell Tumors

The majority of metastatic germ cell tumors (GCTs) are cured with cisplatin-based chemotherapy, but 20–30% of patients will relapse after first-line chemotherapy and require additional salvage strategies. The two major salvage approaches in this scenario are high-dose chemotherapy (HDCT) with autologous stem cell transplant (ASCT) or conventional-dose chemotherapy (CDCT). Both CDCT and HDCT have curative potential in the management of relapsed/refractory GCT. However, due to a lack of conclusive randomized trials, it remains unknown whether sequential HDCT or CDCT represents the optimal initial salvage approach, with practice varying between tertiary institutions. This represents the most pressing question remaining for defining GCT treatment standards and optimizing outcomes. The authors review prognostic factors in the initial salvage setting as well as the major studies assessing the efficacy of CDCT, HDCT, or both, describing the strengths and weaknesses that formed the rationale behind the ongoing international phase III “TIGER” trial.

Clinical experience with plerixafor as a mobilization regimen for autologous peripheral blood stem cell transplantation in patients with refractory germ cell tumors

The purpose of this study was to report our experience with administration of plerixafor for the mobilization of hematopoietic stem cells (HSCs) in patients with refractory or recurrent germ cell tumors who were candidates for salvage therapy with high-dose chemotherapy and HSC transplantation and for whom mobilization of HSCs had not been achieved by standard therapies. This retrospective and observational study selected patients who were eligible for autologous HSC transplantation (AHSCT) and received plerixafor after failure of HSC mobilization by granulocyte colony-stimulating factor (G-CSF). A total of 5 patients (4 male and 1 female), aged 19-41 years (mean age, 29.6 years) were initially selected. Four patients (80%) achieved an adequate HSC mobilization with plerixafor and subsequently received high-dose chemotherapy followed by HSC transplantation. In these patients, the number of CD34⁺ cells collected following plerixafor mobilization was 1.8×10⁶-10.3×10⁶ cells/kg, with a peak CD34⁺ cell count of 7.0-32.0 cells/μl. Following HSC infusion, these 4 patients achieved a neutrophil count of >0.5×10³/mm³ and a platelet count of >20,000/μl between days 10 and 14. Therefore, patients with high-risk germ cell tumors eligible for AHSCT who are refractory to mobilization by G-CSF, may benefit from the use of plerixafor, possibly to the same extent as patients with lymphoma and multiple myeloma.