Abstract
Since 2001, 50 breast cancer patients, for whom extensive lung/heart involvement was expected from the use of conventional tangential 2-field technique (2F) owing to complex anatomies, were irradiated using a 3-field conformal technique (3F). Dose plans were designed for both 3F and 2F and a dose volume histogram analysis on ipsilateral lung, heart, and target was conducted. The 3F technique allowed a significant reduction in ipsilateral lung irradiation: mean dose dropped from 16.0±3.8 (2F) to 12.0±2.7 Gy (3F) and V45Gy from 20.7±6.8 (2F) to 3.2±2.9% (3F). Similarly, in patients irradiated to the left breast, heart mean dose was reduced from 8.1 Gy (2F) to 6.8 Gy (3F) and D15% from 19.0 Gy to 14.0 Gy. All differences reached a high degree of significance. The target coverage was not clinically compromised since the slight reduction using 3F compared with 2F is limited to V95% while V90% difference, even if statistically significant, is small: 98.2±1.8% (3F) and 98.8±1.6 (2F). A preliminary report on clinical follow up is also included; with a mean follow up of 15.8 months, no pulmonary or cardiac complications were observed.
From the Oncology Institute of Southern Switzerland, Medical Physics Unit (L. Cozzi, A. Fogliata, G. Nicolini), Radiation Oncology (J. Bernier), Bellinzona, Switzerland, and the Department of Physics, University of Milan, Italy (T. Rancati)
From the Oncology Institute of Southern Switzerland, Medical Physics Unit (L. Cozzi, A. Fogliata, G. Nicolini), Radiation Oncology (J. Bernier), Bellinzona, Switzerland, and the Department of Physics, University of Milan, Italy (T. Rancati)