A method and apparatus for treating masses, such as prostate or breast cancer, or any other soft tissue cancerous or benign mass, employs a unique, three-dimensional software-controlled electronic amplifier array using arbitrary waveforms that dynamically and proportionally steer electrical currents by using two or more current vector paths, sequentially or simultaneously, through a mass containing electrically-conductive ionic solutions so as to obtain 100% thermal beating or hyperthermia through the mass, and destroying it with a minimally-invasive treatment which requires no radiation or chemotherapy which could be harmful to the patient.