Predicting Chemotherapy Efficacy in Germ Cell Tumors via Blood Tests

Researchers from the Princess Máxima Center, in collaboration with experts from Italy and Slovakia, have investigated whether fragments of tumor DNA in the blood can predict the effectiveness of chemotherapy for young adults with germ cell tumors where standard treatment is insufficient.

The study explored if minimally invasive blood tests could offer crucial insights into treatment outcomes, especially in challenging cases of germ cell tumors.

Methodology

Blood samples from 69 patients receiving high-dose chemotherapy and 26 patients receiving standard chemotherapy in Italy and Slovakia were analyzed. The researchers used shallow whole-genome sequencing to assess circulating tumor DNA (cfDNA) for tumor fraction (TF) and copy number alterations (CNAs). These findings were then rigorously compared with progression-free survival and overall survival, and with an existing biomarker, miR-371a-3p.

Key Findings

• Tumor fraction was detected in 75% of patients treated with high-dose chemotherapy. Crucially, a high tumor fraction correlated with poorer survival in both high-dose and standard-dose chemotherapy groups.
• The biomarker miR-371a-3p was effective in detecting the presence of disease but did not predict survival.
• Specific genetic alterations, including 3p gain, 9q and 11q gains, and 6q loss, were more prevalent in high-dose chemotherapy patients with a poor prognosis.
• Histological subtypes with abnormalities consistent with extra-embryonic histology (yolk sac tumor and choriocarcinoma) were associated with worse survival outcomes.
• High-dose chemotherapy appeared more effective than standard chemotherapy in patients exhibiting a high tumor fraction.

Implications and Next Steps

Analysis of cfDNA provides valuable prognostic information for germ cell tumors that do not respond to or recur after standard chemotherapy.

These minimally invasive biomarkers may enhance risk stratification and assist in treatment decisions, particularly concerning the initiation of intensive chemotherapy in relapsed cases. The insights could also aid in identifying new targets for the development of less toxic treatments.

Further research is required before clinical implementation. The team plans to validate these findings in a larger, international cohort that includes adolescents and children with germ cell tumors. Successful validation could lead to personalized treatment approaches and the exploration of more effective treatments with fewer side effects.

Background on Germ Cell Tumors

Germ cells are precursors to sperm and eggs. Cancer can develop from these cells, primarily affecting boys and young men in the testis and other body sites. Approximately 30 children and 850 young men are diagnosed with germ cell tumors annually in the Netherlands. For one in ten young adults, standard chemotherapy is ineffective, and half of this group ultimately dies despite high-dose chemotherapy.

This research was supported by Stichting Kinderen Kankervrij (KiKa) and the Italian Ministry of Health and was published in the Journal of Clinical Oncology.