Supplementary Material for: Tumor Treating Fields (TTFields) Therapy and Lomustine Chemotherapy for the Treatment of Unresectable Progressive Glioblastoma

Introduction: Tumor Treating Fields (TTFields) therapy used concomitantly with maintenance temozolomide through second progression after radio-chemotherapy, is associated with improved survival outcomes compared to adjuvant temozolomide alone in individuals with newly-diagnosed (nd) glioblastoma (GBM). Lomustine (CCNU) is frequently used as monotherapy or concomitant with other chemotherapy regimens as second-line treatment for recurrent GBM (rGBM).
Case presentation: We report a 59-year-old female patient diagnosed with MGMT-promoter methylated (mMGMT), isocitrate dehydrogenase-wildtype (IDHwt) GBM (World Health Organization Grade 4) who received TTFields therapy concomitant with first- and second-line chemotherapy following partial resection. The patient experienced tumor pseudoprogression/progression after three cycles of maintenance temozolomide/TTFields therapy and again after a further two cycles of procarbazine/CCNU/TTFields therapy, and was then switched to CCNU/TTFields therapy. During 18 months of treatment with concomitant TTFields therapy and CCNU, the patient experienced regression/reduction of both tumor volume and perifocal edema with tolerable hematotoxicity, and was able to maintain a high rate of TTFields therapy usage. The patient ultimately died after developing chemotherapy-related acute myeloid leukemia.
Conclusion: This patient case is reflective of the EF-14 outcome using TTFields therapy beyond first progression concomitantly with chemotherapy. The observations from this case suggest that TTFields therapy concomitant with CCNU is a valuable treatment modality in patients with GBM, in this context.