Bilateral breast cancer: radiation therapy results and technical considerations

A retrospective review was done of 34 women with bilateral breast carcinoma who received bilateral breast irradiation from 1964 to 1979. For the 31 curative patients, the 10-year actuarial survival rate after completion of irradiation to the second primary was 67%. Based upon the development of bilateral medial subcutaneous fibrosis/necrosis in 3/15 long-term survivors, various technical problems unique to bilateral breast irradiation were examined: In metachronous presentations, the dose to the contralateral subcutaneous medial tissue was determined as a function of the distance across the midline and the total dose that this point should receive if future contralateral IMC irradiation is required also. In synchronous presentations the doses to the spinal cord and anterior pericardium were determined for bilateral IMC irradiation as a function of modality, field width and energy. Suggestions for solving these technical problems are made, and the importance of permanent skin markings documenting portal placement to aid in possible future contralteral breast irradiation is stressed