Radiation dose to the left anterior descending coronary artery during interstitial pulsed-dose-rate brachytherapy used as a boost in breast cancer patients undergoing organ-sparing treatment

Abstract

PurposeTo assess dose received by the left anterior descending (LAD) coronary artery during interstitial pulsed-dose-rate brachytherapy (PDR-BT) boost for left-sided breast cancer patients undergoing organ-sparing treatment.Material and methodsThirty consecutive pT1-3N0-1M0 breast cancer patients boosted between 2014 and 2015 with 10 Gy/10 pulses/hour PDR-BT following a computed tomography (CT) simulation with the multi-catheter implant were included. The most common localization of primary tumor were upper quadrants. Patients were implanted with rigid tubes following breast conserving surgery and whole breast external beam irradiation (40 Gy/15 or 50 Gy/25 fractions). Computed tomography scans were retrospectively reviewed and LADs were contoured without and with margin of 5 mm (LAD5mm). Standard treatment plan encompassed tumor bed determined by the surgical clips with margin of 2 cm. Dosimetric parameters were extracted from the dose-volume histograms.ResultsThe mean D90 and V100 were 10.3 Gy (range: 6.6-13.3), and 42.0 cc (range: 15.3-109.3), respectively. The median dose non-uniformity ratio (DNR) was 0.50 (range: 0.27-0.82). The mean doses to LAD and LAD5mm were 1.0 Gy and 0.96 Gy, and maximal doses were 1.57 Gy and 1.99 Gy, respectively. Dose to the 0.1 cc of the LAD and LAD5mm were 1.42 Gy and 1.85 Gy (range: 0.01-4.98 Gy and 0.1-6.89 Gy), respectively.ConclusionsInterstitial multi-catheter PDR-BT used as a boost for left-sided breast cancer is generally associated with low dose to the LAD. However, higher dose in individual cases may require alternative approaches.

Heart dose and coronary artery calcification in patients receiving thoracic irradiation for lung cancer

“…Micro-and macro-vascular injury in tissues receiving radiotherapy is considered the main cause of radiation-induced heart disease (7). Radiotherapy causes acute endothelial inflammation leading to the mobilization of granulocytes, monocytes, and macrophages that may lead to fibrosis and marked thickening of the adventitia and media of the arteries (8). Eventually this leads to stenosis and calcifications and accelerates progression to unstable atherosclerosis.…”

“…According to Darby et al, the mean heart dose was a better predictor of the rate of major coronary events than the mean dose to the LAD (7). However, despite the historical changes in radiotherapy techniques and heart doses, the LAD lying on the anterior myocardial wall still received an average dose of 20 Gy during breast cancer treatment in the 1980s and has been linked to a risk of ischemic heart disease for years after radiotherapy (8). In our study, the average mean and maximum doses to the proximal LAD were approximately 19.86 and 30.68 Gy, respectively.…”

“…Each additional gray (Gy) to the heart was associated with a 7.4% increase in coronary events (95% CI, 2.9-14.5, P<0.001) (7). Additionally, the anterior location of the left anterior descending (LAD) coronary artery suggests that radiation to the LAD may also serve as an independent predictor of cardiovascular events (8).…”

Radiotherapy for primary angiosarcoma of the breast: a case report

“…3 Primary angiosarcoma of the breast tends to metastasize hematogenous to lungs, liver, bones, skin and the contralateral breast (from the other breast). 4, 7 The prognosis of the angiosarcoma of the breast is generally poor and based primarily on tumor size, histologic type of sarcoma, tumor grade, completeness of surgery/the resection margin status, and performance status. However, the factors related to the prognosis of primary breast angiosarco ma have still controversial.…”