Radiation dose distribution in coronary arteries in breast cancer radiotherapy

<p><b>Background:</b> Women irradiated for left-sided breast cancer (BC) have an increased risk of coronary artery disease compared to women with right-sided BC. We describe the distribution of radiation dose in segments of coronary arteries in women receiving adjuvant radiotherapy (RT) for left- or right-sided BC.</p> <p><b>Material and methods:</b> Fifteen women with BC, seven left-sided and eight right-sided, who had received three-dimensional conformal radiotherapy (3DCRT), constituted the study base. The heart and the segments of the coronary arteries were defined as separate organs at risk (OAR), and the mean and maximum radiation doses were calculated for each OAR.</p> <p><b>Results:</b> In women with left-sided BC, irrespective of if regional lymph node RT was given or not, maximum dose in mid and distal left anterior descending artery (mdLAD) was approximately 50 Gy in 6/7 patients, whereas women with right-sided BC mainly received low doses of radiation. In women with left-sided BC, 6/7 patients had substantially higher mean dose to the distal LAD than to the heart, ranging from 30 to 55 Gy and 3 to13 Gy, respectively.</p> <p><b>Conclusion:</b> We found a pronounced difference of radiation dose distribution in the coronary arteries between women with left- and right-sided BC. Women with left-sided BC had almost full treatment dose in parts of mdLAD, regardless of if regional lymph node irradiation was given or not, while women with right-sided BC mainly received low doses to the coronary arteries.</p

Complications after proton radiotherapy in children, focusing on severe late complications. A complete Swedish cohort 2008–2019

Proton radiotherapy (RT) is an attractive tool to deliver local therapy with minimal dose to uninvolved tissue, however, not suitable for all patients. The aim was to explore complications, especially severe late complications (grades 3–4), following proton RT delivered to a complete Swedish cohort of paediatric patients aged Data was downloaded from a national registry. Complications with a possible causation with RT are reported. Proton treatments until July 2015 was performed with a fixed horizontal 172 MeV beam (The Svedberg Laboratory (TSL), Uppsala) in a sitting position and thereafter with gantry-based pencil-beam scanning technique (Skandion Clinic, Uppsala) in a supine position. 219 courses of proton RT (77 at TSL and 142 at Skandion) were delivered to 212 patients (mean age 9.2 years) with various tumour types (CNS tumours 58%, sarcomas 26%, germ cell tumours 7%). Twenty-five patients had severe acute complications (skin, mucous membrane, pharynx/oesophagus, larynx, upper gastrointestinal canal, lower gastrointestinal canal, eyes, ears). Fifteen patients had severe late complications; with increased proportion over time: 4% at 1-year follow-up (FU), 5% at 3-year, 11% at 5-year. Organs affected were skin (1 patient), subcutaneous tissue (4), salivary glands (1), upper GI (1), bone (7), joints (2), CNS (2), PNS (1), eyes (1) and ears (5). Twenty-one of the 28 patients with 10-year FU had at least one late complication grades 1–4 and fourteen of them had more than one (2–5 each). The most important result of our study is the relatively low proportion of severe late complications, comparable with other proton studies on various tumours. Furthermore, the numbers of late complications are lower than our own data set on a mixed population of photon and proton treated paediatric patients, assuring the safety of using proton therapy also in the clinical practice.</p