Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group.

Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies.

Pre-Implementation Assessment of the Acceptability of Using Circulating microRNAs for Follow-Up of Malignant Germ-Cell Tumors.

BACKGROUND: MicroRNAs from the miR-371~373 and miR-302/367 clusters, particularly miR-371a-3p, are promising biomarkers for blood-based diagnosis and disease monitoring of malignant germ cell tumors (GCTs) and are nearing clinical implementation. These biomarkers have superior sensitivity and specificity compared with current markers alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG). We explored patient acceptability of using circulating microRNAs to replace multiple serial computed tomography (CT) scans in malignant GCT follow-up. PATIENTS AND METHODS: Two workshops involved interactive presentations and focus groups. Discussions were digitally recorded and transcribed verbatim. Qualitative thematic analysis of transcripts identified the key themes. RESULTS: Prior to the workshops, potential participants expressed concern about the adoption of new blood tests due to personal experiences of the limitations of existing (AFP/HCG) markers. Twelve males (22-57 years of age; currently, 26-59 years of age) with a malignant GCT diagnosis participated; all were in follow-up. Three had experienced recurrence. Participants had cumulative exposure of between 1 and 15 CT scans. Data saturation was reached at the second workshop; five themes emerged underpinning preference for microRNA testing versus CT scans: (1) increased sensitivity and safety, (2) reduced financial costs, (3) reduced time for testing and results, (4) practicalities, and (5) reduced anxiety. However, some participants perceived an increased diagnostic capacity of CT scans versus blood testing. CONCLUSION: This first user consultation of circulating microRNA testing for future malignant GCT follow-up suggests high acceptability with potential patient and healthcare system benefits.

Impact of circulating microRNA test (miRNA-371a-3p) on appropriateness of treatment and cost outcomes in patients with Stage I non-seminomatous germ cell tumours.

OBJECTIVES: To determine whether utilisation of a serum microRNA (miRNA) test could improve treatment appropriateness and cost-effectiveness for patients with Stage I non-seminomatous germ cell tumours (NSGCTs). PATIENTS AND METHODS: A decision tree model was built to investigate treatment course, clinical and cost outcomes for patients with Stage IA (T1N0M0S0) and IB (T2-4N0M0S0) NSGCT. The model compared outcomes and cost of standard approach using histopathology, conventional serum tumour markers and radiographic staging (standard model) to a miRNA-based approach using the standard model + post-orchidectomy serum miR-371a-3p (marker model). Probabilities of expected treatment and outcomes were based on presence/absence of cancer upon entering into the model. Overtreatment was defined as adjuvant chemotherapy or primary retroperitoneal lymph node dissection in a patient without cancer. Undertreatment was defined as initial surveillance for a patient with cancer. RESULTS: Utilising the miRNA marker-based approach, 26% of patients avoid overtreatment and 8% avoid undertreatment in Stage IA NSGCT; 27% avoid overtreatment and 23% avoid undertreatment in Stage IB disease. Appropriate treatment decision-making increased from 65% to 94% and 50% to 92% for Stage IA and IB, respectively. The miRNA-based approach remained cost-effective over a wide range of performance characteristics with savings of ~$1400 (American dollars)/patient for both Stage IA and IB disease. CONCLUSION: A miRNA-based approach may potentially select patients with Stage I NSGCT for correct treatment in a cost-effective manner. Identification of residual teratoma-only remains an issue. Prospective studies are necessary to validate these findings.

Symptom interval and treatment burden for patients with malignant central nervous system germ cell tumours.

OBJECTIVE: Patients with central nervous system germ cell tumours (CNS-GCTs) commonly initially present to primary care or general paediatricians. Prolonged symptom intervals (SI) are frequently seen in CNS-GCTs and have been associated with inferior outcomes in other brain tumours. This study reviewed the clinical presentation of CNS-GCTs and examined the effect of prolonged SI. DESIGN/SETTING/PATIENTS/OUTCOMES: International multicentre 10-year retrospective study (2002-2011 inclusive), across six international paediatric oncology treatment centres. All newly diagnosed patients with CNS-GCT were included. Main outcome measure was time interval from first symptom to diagnosis. RESULTS: The study cohort included 86 (58 males:28 female) patients (59 'germinoma' and 27 'non-germinomatous' GCTs), with tumours being pineal (n=33), suprasellar (n=25), bifocal (pineal+suprasellar; n=24) and 'other' site (n=4), of which 16 (19%) were metastatic. Median age at diagnosis was 14 years (0-23 years). The time to diagnosis from first symptom (SI) was 0-69 months (median 3 months, mean 9 months). A prolonged SI (>6 months) was observed in 28/86 patients (33%) and significantly associated with metastatic disease (11/28 (39%) vs 5/58 (9%); p=0.002)) at diagnosis, but not overall survival. With prolonged SI, endocrine symptoms, particularly diabetes insipidus, were more common (21/28 (75%) vs 14/58 (24%) patients; p<0.002), but raised intracranial pressure (RICP) was less frequent (4/28 (14%) vs 43/58 (74%) patients; p<0.001)) at first symptom. CONCLUSIONS: One-third of patients with CNS-GCT have >6 months of symptoms prior to diagnosis. Delayed diagnosis is associated with metastatic disease. Early symptom recognition, particularly related to visual and hormonal disturbances in the absence of RICP, may improve timely diagnosis, reduce metastatic disease frequency and consequently reduce treatment burden and late effects.

Cost Analysis of Noninvasive Blood-Based MicroRNA Testing Versus CT Scans for Follow-up in Patients With Testicular Germ-Cell Tumors.

BACKGROUND: Our group has developed a noninvasive blood-based microRNA (miRNA) test for improving diagnosis, disease monitoring, and relapse detection in malignant testicular germ-cell tumors (TGCTs). Performance analysis suggests the test is likely to have comparable sensitivity and specificity in detecting TGCT as computed tomography (CT), thus reducing the need for serial CT scans for follow-up monitoring, with associated reductions in cumulative radiation burden and second cancer risk. To facilitate clinical adoption, we undertook a cost analysis to identify the budget impact of replacing CT scans with miRNA testing within health care systems. METHODS: The TGCT aftercare pathway was mapped out using National Comprehensive Cancer Network guidelines. A Markov model was built to simulate the impact of the miRNA test on TGCT aftercare costs. Incidence, treatment probabilities, relapse rate, and death rate data were collected from published studies to populate the model. RESULTS: Applying our model to the US health care system, the miRNA test has the potential to save up to $69 million per year in aftercare expenses related to TGCT treatment, with exact savings depending on the adoption rate and test price. CONCLUSION: This analysis demonstrates the potential positive budget impact of adopting miRNA testing in place of CT scans in the clinical management of TGCTs.