Reduction of Dose to the Contralateral Breast by Superflab Use in Radiation Therapy for Mammary Carcinomas

Abstract

<br /> <strong><span style="font-size: small;">Background: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Radiation therapy is an integral part of multimodality treatment for locally advanced carcinoma of breast. Radiation doses to nearby critical normal structures like heart, lungs, and contralateral breast (CLB increases risk </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">of second malignancies. In this study, we measured doses to the CLB and studied effects of a 1 cm thickness superflap. </span></span><strong><span style="font-size: small;">Materials and Methods: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Fifty post-mastectomy carcinoma breast patients were included in the study.Radiation therapy of 50 Gy was planned in 25 fractions, 5 days a week, using the Eclipse Treatment Planning System version 8.9.15, with a pencil beam convolution algorithm and 6 MV photon beam. Plans were transferred to a linear accelerator (Varian 2300 CD) for execution of treatment. Twenty-four CaSO4 thermoluminescent dosimeter discs (TLDs) were used for dose </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">measurement over the CLB. The dose was measured for each patient without a superflab for ten fractions and with for </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">another ten fractions for subsequent comparison. </span></span><strong><span style="font-size: small;">Results: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Mean doses/fractions received by the CLB with and without </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">a superflab? were 3.78 ± 1.29 cGy and 7.82 ± 2.62 cGy, respectively, with total dosees of 94.69 ± 32.43 cGy (1.89% of prescribed dose) and 191.14 ± 65.62 cGy (3.82% of prescribed dose). The average reduction in mean dose with a 1 cm thick superflab was 46.57 ± 17.18%, in the range of 20 to 80% and statistically significant (p < 0.001). </span></span><strong><span style="font-size: small;">Conclusion: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Superflab? is an effective method for dose reduction to CLB. It is an easy, convenient and low time consuming method. </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Elucidation of any role in reduction of 2nd malignancies in CLB now needs large studies with long follow-up. </span></span>