Dosimetric Evaluation of 3-D Conformal and Intensity-modulated Radiotherapy for Breast Cancer after Conservative Surgery

Abstract

Background: Breast cancers are becoming more frequently diagnosed at early stages with improved long term outcomes. Late normal tissue complications induced by radiotherapy must be avoided with new breast radiotherapy techniques being developed. The aim of the study was to compare dosimetric parameters of planning target volume (PTV) and organs at risk between conformal (CRT) and intensity-modulated radiation therapy (IMRT) after breast-conserving surgery. Materials and Methods: A total of 20 patients with early stage left breast cancer received adjuvant radiotherapy after conservative surgery, 10 by 3D-CRT and 10 by IMRT, with a dose of 50 Gy in 25 sessions. Plans were compared according to dose-volume histogram analyses in terms of PTV homogeneity and conformity indices as well as organs at risk dose and volume parameters. Results: The HI and CI of PTV showed no difference between 3D-CRT and IMRT, V95 gave 9.8% coverage for 3D-CRT versus 99% for IMRT, V107 volumes were recorded 11% and 1.3%, respectively. Tangential beam IMRT increased volume of ipsilateral lung V5 average of 90%, ipsilateral V20 lung volume was 13%, 19% with IMRT and 3D-CRT respectively. Patients treated with IMRT, heart volume encompassed by 60% isodose (30 Gy) reduced by average 42% (4% versus 7% with 3D-CRT), mean heart dose by average 35% (495cGy versus 1400 cGy with 3D-CRT). In IMRT minimal heart dose average is 356 cGy versus 90cGy in 3D-CRT. Conclusions: IMRT reduces irradiated volumes of heart and ipsilateral lung in high-dose areas but increases irradiated volumes in low-dose areas in breast cancer patients treated on the left side.

Displacement of Surgical Clips during Postoperative Radiotherapy in Breast Cancer Patients Who Received Breast-Conserving Surgery

“…Recently, intensity-modulated radiotherapy (IMRT) has been adopted to treat patients with breast cancer. The heart, coronary arteries, and lungs can be saved from a high dose radiation using IMRT [1314]. External beam-partial breast irradiation using IMRT also can be considered for selected patients.…”

Dosimetric evaluation of the skin-sparing effects of 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy for left breast cancer

“…Several studies have revealed that the target volume coverage was improved and the dose delivered to OARs was reduced in IMRT compared to 3D-CRT [3, 5, 6]. In this study, the higher dose delivered to the heart and the mean dose of the heart were effectively reduced, and the higher dose delivered to the lung was also reduced in IMRT than in 3D-CRT.…”

“…When compared to traditional 3-dimensional conformal radiotherapy (3D-CRT), IMRT enhances the target volume coverage and effectively reduces the higher dose delivered to organs at risk (OARs) such as the heart, ipsilateral lung, and so on [3]. In the case of radiation-related dermatitis, it has been reported that IMRT reduced severe acute skin toxicity according to the Radiation Therapy Oncology Group (RTOG) criteria [4].…”

Hybrid intensity-modulated radiation therapy (IMRT) simultaneous integrated boost (SIB) technique versus three-dimensional (3D) conformal radiotherapy with SIB for breast radiotherapy: a planning comparison

“…Dramatic reduction of high doses to the lung evident in the hybrid plans can be attributed to the inclusion of IMRT, though conversely the IMRT also creates additional scatter thereby increasing low-dose regions as reported by other studies. 4,13,14 Furthermore, beam angles chosen in the hybrid plans to treat the boost contribute to a higher V5. Further investigation into this hybrid technique to reduce V5 doses could involve selection of angles that reduce exit to the ipsilateral lung.…”

“…Unfortunately, IMRT can increase the volume of low dose received to the organs at risk (OARs) and healthy tissue. [12][13][14][15] A more recent alternative to 3D conventional or IMRT treatment is a hybrid approach, combining the two techniques with the aim to create a more optimised dosimetric outcome. This technique involves a certain percentage of the prescription dose (e.g., 70%) delivered via tangential beams with no beam modifiers.…”