Perhaps doing some research would show you that is not true. Optune had 5 year overall survival of 13% vs. 5% for the comparator. From the ASCO Post:
A landmark analysis showed improved survival for the combination of tumor-treating fields plus temozolomide vs temozolomide alone at 2 (43% vs 31%, respectively), 3 (26% vs 16%), 4 (20% vs 8%), and 5 years (13% vs 5%) from randomization.