Intensity modulated radiation therapy (IMRT) technique for left breast cancer by different numbers of beam fields

Intensity Modulated Radiotherapy (IMRT) can improve radiotherapy (RT) results by improving healthy tissue sparing. Additionally, IMRT provides more consistent dose deliveries and suppresses secondary tumor formation. RT is a principal treatment in breast cancer (BC).

To evaluate the outcome of the Radiotherapy Plans (RTP) that use IMRT technique to left breast and other organs, including left lung (Lt lung), right lung (Rt lung), heart, and spinal cord.

Thirteen patients with left-sided breast carcinoma were treated using IMRT.

The Homogeneity Index (HI) and Conformity Index (CI) showed significant improvement over IMRT-involved plans. All IMRT plans significantly improved CI for 12 patients, where CI <1. Planning target volume (PTV) was under coverage, except for patient No. 6, where CI>1. HI for 13 patients.  Mean dose to heart, Lt lung, and Rt lung was (9.966±1.261), (14.388±0.854), and (4.083±0.661) of the prescribed dose, respectively. Cord Max, Dose was (Gy) (20.751±7.384), and Cord Received Max Dose was <45Gy.  Mean heart dose was (9.966±1.261) (Gy), and the PTV mean dose was (41.169±0.437) (Gy). Mean dose to lungs for eight patients was <30Gy, except for five patients (No. 1, 2, 5, 12, and 13), which received >30Gy.

The IMRT plans achieved a significant reduction in heart volume and ipsilateral lung exposed to high-dose (≥40.05 Gy).  Multi-beam inverse planned IMRT technique might benefit patients with heart diseases, and who are exposed to doses <20 Gy, irrespective of the selected plan.  Relative volume of ipsilateral lung or heart receiving high-dose (40.05 Gy) was significantly reduced.