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EF-14 Phase III post-hoc analysis – TTFields affect tumour growth rates
Post-Hoc Analyse der EF-14 Phase III Studie – TTFields beeinflussen die Tumorwachstumsraten
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Veröffentlicht: | 26. Juni 2020 |
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Gliederung
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Objective: The pivotal EF-14 study on newly diagnosed glioblastoma (nGBM) patients demonstrated that combining TTFields with maintenance temozolomide significantly extends progression-free survival (PFS) compared to temozolomide treatment alone (6.7 vs 4.0 months, p<0.001). It can be hypothesized that TTFields treatment leads to local tumor control and significantly decreased tumor growth rates. In order to test this hypothesis, we analyzed patients from the EF-14 phase III study who received only a biopsy.
Methods: Our analysis included patients from the EF-14 study who received biopsy and showed radiological progression (treatment: N=37/60, control: N=12/29). In a first step, the volumes of the enhancing tumors were segmented on T1c MRIs both at baseline and later at progression. In a second step, we calculated the tumor growth rate as following:
growth_rate=(ln(v0)-ln(v1))/dt. (v0 - tumor volume at baseline), v1 - Tumor volume at progression, dt - days to progression).
This models tumor volume as increasing exponentially over time. Finally, we compared the median growth rates between control and treatment arm.
Results: The calculations demonstrate that the median growth rate was lower in the treatment arm compared to the control (control: 0.14 ± 0.12 mL/month, TTFields -0.011± 0.11 mL/month, p< 0.008 Wilcoxon rank-sum).
Conclusion: Our post-hoc analysis of EF-14 demonstrated that tumor growth rates are reduced in the combined TTFields+TMZ arm when compared to TMZ alone. The analysis only included patients that received a biopsy. The reason for this is that defining the volume of a tumor in resected patients is ambiguous because of the fact that part of the tumor was removed. In summary, our results suggest that TTFields enhances local tumor control.
References
- 1.
- Stupp R, Taillibert S, Kanner A, et al. Effect of Tumor-Treating Fields Plus Maintenance Temozolomide vs Maintenance Temozolomide Alone on Survival in Patients With Glioblastoma: A Randomized Clinical Trial. JAMA. 2017;318(23):2306-16. DOI: 10.1001/jama.2017.18718
- 2.
- Stensjoen AL, et al. Growth Dynamics of Untreated Glioblastomas in Vivo. Neuro Oncol. 2015 Oct;17(10):1402-11. DOI: 10.1093/neuonc/nov029