Combined millimeter wave and cyclophosphamide therapy of an experimental murine melanoma

The objective of the present studies was to investigate whether millimeter wave (MMW) therapy can increase the efficacy of cyclophosphamide (CPA), a commonly used anti-cancer drug. The effect of combined MMW-CPA treatment on melanoma growth was compared to CPA treatment alone in a murine model. MMWs were produced with a Russian made YAV-1 generator. The device produced 42.2 +/- 0.2 GHz modulated wave radiation through a 10 x 20 mm rectangular output horn. The animals, SKH-1 hairless female mice, were irradiated on the nasal area. Peak SAR and incident power density were measured as 730 +/- 100 W/kg and 36.5 +/- 5 mW/cm2, respectively. The maximum skin surface temperature elevation measured at the end of 30 min irradiation was 1.5 degrees C. B16F10 melanoma cells (0.2 x 10(6)) were implanted subcutaneously into the left flank of mice on day 1 of the experiment. On days 4-8, CPA was administered intraperitoneally (30 mg/kg/day). MMW irradiation was applied concurrently with, prior to or following CPA administration. A significant reduction (P < .05) in tumor growth was observed with CPA treatment, but MMW irradiation did not provide additional therapeutic benefit as compared to CPA alone. Similar results were obtained when MMW irradiation was applied both prior to and following CPA treatment.