Low cardiac and left anterior descending coronary artery dose achieved with left-sided multicatheter interstitial-accelerated partial breast irradiation

Abstract

<div class="section"> <a class="named-anchor" id="S1"> <!-- named anchor --> </a> <h5 class="section-title" id="d2772760e174">PURPOSE:</h5> <p id="P1">Studies have shown that an additional mean dose of 1 gray to the heart can increase the relative risk of cardiac events. The purpose of this study was to quantify the dose delivered to the heart and left anterior descending artery (LAD) in a series of patients with left-sided breast cancer or DCIS treated with multi-catheter accelerated partial breast irradiation (MC-APBI) at a single institution. </p> </div><div class="section"> <a class="named-anchor" id="S2"> <!-- named anchor --> </a> <h5 class="section-title" id="d2772760e179">METHODS AND MATERIALS:</h5> <p id="P2">Patients with left-sided breast cancer or DCIS treated consecutively from 2005 to 2011 with MC-APBI were retrospectively identified. Cardiac and LAD contours were generated for each patient. Cardiac dosimetry and distance to the planning target volume (PTV) were recorded. Patient health records were reviewed and cardiac events were recorded based on Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. </p> </div><div class="section"> <a class="named-anchor" id="S3"> <!-- named anchor --> </a> <h5 class="section-title" id="d2772760e184">RESULTS:</h5> <p id="P3">Twenty consecutive patients with left-sided breast cancer treated with MC-APBI were retrospectively identified. Median follow-up was 41.4 months. Mean EQD2 delivered to the heart and LAD were 1.3 (standard deviation: 0.7, range: 0.2–2.9) and 3.8 (standard deviation: 3.0, range: 0.4–11.3) Gy, respectively. There was an inverse linear relationship (R ²=0.52) between heart-to-lumpectomy cavity distance and mean heart EQD2. One patient (5%) experienced symptomatic cardiac toxicity. </p> </div><div class="section"> <a class="named-anchor" id="S4"> <!-- named anchor --> </a> <h5 class="section-title" id="d2772760e192">CONCLUSIONS:</h5> <p id="P4">MC-APBI consistently delivers average doses to the heart and LAD that are similar to those achieved in most series with deep inspiration breath-hold, and lower than free breathing radiotherapy techniques. Distance from the heart to the lumpectomy cavity and the availability of other heart-sparing technologies should be considered to minimize the risk of cardiac toxicity. </p> </div>