Methods and systems apply biphasic DC signal at various frequencies, durations and/or amplitudes to areas of a cancer patient's body being targeted for preventing or alleviating cancer-therapy side effects. Microcurrent therapy can be provided prior to, during and after procedures used to treat cancer. During microcurrent treatment a biphasic DC signal can be applied from a microcurrent therapy system to an area of the cancer patient's body targeted for microcurrent treatment using at least one electrode. The electrode can be actively manipulated on the treatment area for a predetermined time. The system can provide impedance matching between it and the patient during treatment. A feedback module provides a controller impedance information between the patient and system where a mismatch is used to adjust the system to overcome impedance variations that occur between said system and said patient's body during the predetermined time of treatment.