The 1997 International Germ Cell Cancer Collaborative Group (IGCCCG) prognostic model, which divided patients into pre-chemotherapy risk groups by histology, tumor location, and serum tumor markers, has been pragmatic and easy to use. However, it has been known for some time that there is considerable heterogeneity within the risk groups. Perhaps the most impactful illustration of this heterogeneity is the GETUG 13 trial, which personalized chemotherapy regimens for poor-risk germ cell tumor patients based on the decline in serum tumor markers after one cycle of chemotherapy. The authors of that study showed that offering intensified chemotherapy to patients who did not have a favorable reduction in tumor markers with chemotherapy improved progression-free survival. The new prognostic model seems to have identified a similar especially poor-risk group within the standard poor-risk classification, and these patients can now be prospectively identified for clinical trial protocols.
The data from Gillessen and colleagues indicates that patient outcomes have improved since the publication of the initial prognostic model in 1997. He suggested that there are multiple reasons for this including
- Improved accuracy of diagnosis
- A better understanding of the nuances of elevated tumor markers and equivocal imaging findings
- Improvements in the surgical management of this disease
- Better supportive care, especially for nausea and vomiting, for chemotherapy
- Improved management of thrombotic risk
- Improved post-treatment surveillance procedures
Finally, Dr. Oldenburg and the audience proposed a few caveats to the new model. These include
- Absence of newer prognostic tumor markers such as miR-371a-3p
- Data was generated from high-volume centers, which may not reflect outcome and risk in lower-volume treatment locations
- The data does not adequately represent patients from Eastern Europe, South America and Asia
Importantly, the discussants pointed out that this newer prognostic model is not appropriate for making treatment decisions at this time. The 1997 classification remains the gold standard for stratifying patients and making therapeutic decisions for male patients with disseminated germ cell tumors. However, it is expected that future clinical trials can incorporate this newer prognostic system to optimize care of germ cell tumor patients, especially those with the highest risk of dying from their disease.
Presented by: Jan Oldenburg, MD, PhD, Clinical Oncologist at the University of Oslo, Oslo, NorwayWritten by: Alok Tewari, MD, PhD, Medical Oncology Fellow at the Dana-Farber Cancer Institute, at the 2019 European Society for Medical Oncology annual meeting, ESMO 2019 #ESMO19, 27 Sept - 1 Oct 2019 in Barcelona, Spain