Speleers, Bruno ABruno ASpeleersBelosi, Francesca MFrancesca MBelosiDe Gersem, Werner RWerner RDe GersemDeseyne, Pieter RPieter RDeseynePaelinck, Leen MLeen MPaelinckBolsi, AlessandraAlessandraBolsiLomax, Antony JAntony JLomaxBoute, Bert GBert GBouteVan Greveling, Annick EAnnick EVan GrevelingMonten, Christel MChristel MMontenVan de Velde, Joris JJoris JVan de VeldeVercauteren, Tom HTom HVercauterenVeldeman, LivLivVeldemanWeber, Damien CharlesDamien CharlesWeberDe Neve, Wilfried CWilfried CDe Neve2024-10-282024-10-282019-03-18https://boris-portal.unibe.ch/handle/20.500.12422/182981We report on a dosimetrical study comparing supine (S) and prone-crawl (P) position for radiotherapy of whole breast (WB) and loco-regional lymph node regions, including the internal mammary chain (LN_IM). Six left sided breast cancer patients were CT-simulated in S and P positions and four patients only in P position. Treatment plans were made using non-coplanar volumetric modulated arc photon therapy (VMAT) or pencil beam scanning intensity modulated proton therapy (IMPT). Dose prescription was 15*2.67 Gy(GyRBE). The average mean heart doses for S or P VMAT were 5.6 or 4.3 Gy, respectively (p = 0.16) and 1.02 or 1.08 GyRBE, respectively for IMPT (p = 0.8; p < 0.001 for IMPT versus VMAT). The average mean lung doses for S or P VMAT were 5.91 or 2.90 Gy, respectively (p = 0.002) and 1.56 or 1.09 GyRBE, respectively for IMPT (p = 0.016). In high-risk patients, average (range) thirty-year mortality rates from radiotherapy-related cardiac injury and lung cancer were estimated at 6.8(5.4-9.4)% or 3.8(2.8-5.1)% for S or P VMAT (p < 0.001), respectively, and 1.6(1.1-2.0)% or 1.2(0.8-1.6)% for S or P IMPT (p = 0.25), respectively. Radiation-related mortality risk could outweigh the ~8% disease-specific survival benefit of WB + LN_IM radiotherapy for S VMAT but not P VMAT. IMPT carries the lowest radiation-related mortality risks.en600 - Technology::610 - Medicine & healtharticle10.7892/boris.1346093089460610.1038/s41598-019-41283-1