The non-small-cell-lung-cancer (NSCLC) is a common malignant tumor, and generally not best candidates for hyperthermia due to the cooling effect of the breathing. We present two retrospective clinical studies for NSCLC done by two medical centers (HTT-MED Day-clinic and Peterfy Hospital) made by special modulated field electro-hyperthermia, called oncothermia. Both of the centers made the treatments by oncothermia in combination with the conventional tumor-therapies. We present the data from both of the centers and make a metaanalysis as well. Results show a remarkable survival benefit for the patients compared to the historical data. The comparison of the studies demonstrates a good correspondence in the data, which strengthens the reliability of the studies, and greatly points out the feasibility of the oncothermia application on the NSCLC.