Pengcheng Zhang1, Antoine Simon2, Bastien Rigaud3, Joël Castelli4, Juan David Ospina Arango5, Mohamed Nassef5, Olivier Henry6, Jian Zhu7, Pascal Haigron2, Baosheng Li7, Huazhong Shu8, Renaud De Crevoisier9. 1. National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, People's Republic of China; Université de Rennes 1, LTSI, France; INSERM, U1099, Rennes, France; Centre de Recherche en Information médicale sino-français (CRIBs), Rennes, France. 2. Université de Rennes 1, LTSI, France; INSERM, U1099, Rennes, France; Centre de Recherche en Information médicale sino-français (CRIBs), Rennes, France. 3. Université de Rennes 1, LTSI, France; INSERM, U1099, Rennes, France. Electronic address: bastien.rig@gmail.com. 4. Université de Rennes 1, LTSI, France; INSERM, U1099, Rennes, France; Centre Eugene Marquis, Radiotherapy Department, Rennes, France. 5. Université de Rennes 1, LTSI, France; INSERM, U1099, Rennes, France. 6. Centre Eugene Marquis, Radiotherapy Department, Rennes, France. 7. Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, People's Republic of China; Laboratory of Image Science and Technology, Southeast University, Nanjing, People's Republic of China. 8. Centre de Recherche en Information médicale sino-français (CRIBs), Rennes, France; Laboratory of Image Science and Technology, Southeast University, Nanjing, People's Republic of China. 9. Université de Rennes 1, LTSI, France; INSERM, U1099, Rennes, France; Centre de Recherche en Information médicale sino-français (CRIBs), Rennes, France; Centre Eugene Marquis, Radiotherapy Department, Rennes, France. Electronic address: r.de-crevoisier@rennes.unicancer.fr.
Abstract
PURPOSE: In oropharyngeal cancer adaptive radiation therapy (ART), this study aimed to quantify the dosimetric benefit of numerous replanning strategies, defined by various numbers and timings of replannings, with regard to parotid gland (PG) sparing. MATERIAL AND METHODS: Thirteen oropharyngeal cancer patients had one planning and then six weekly CT scans during the seven weeks of IMRT. Weekly doses were recalculated without replanning or with replanning to spare the PG. Sixty-three ART scenarios were simulated by considering all the combinations of numbers and timings of replanning. The PG cumulated doses corresponding to "standard" IMRT and ART scenarios were estimated and compared, either by calculating the average of weekly doses or using deformable image registration (DIR). RESULTS: Considering average weekly doses, the mean PG overdose using standard IMRT, compared to the planned dose, was 4.1Gy. The mean dosimetric benefit of 6 replannings was 3.3Gy. Replanning at weeks 1, 1-5, 1-2-5, 1-2-4-5 and 1-2-4-5-6 produced the lowest PG mean doses, 94% of the maximum benefit being obtained with 3 replannings. The percentage of patients who had a benefit superior to 5Gy for the contralateral PG was 31% for the three-replannings strategy. The same conclusions were found using DIR. CONCLUSION: Early replannings proved the most beneficial for PG sparing, three replannings (weeks 1-2-5), representing an attractive combination for ART in oropharyngeal cancer.
PURPOSE: In oropharyngeal cancer adaptive radiation therapy (ART), this study aimed to quantify the dosimetric benefit of numerous replanning strategies, defined by various numbers and timings of replannings, with regard to parotid gland (PG) sparing. MATERIAL AND METHODS: Thirteen oropharyngeal cancerpatients had one planning and then six weekly CT scans during the seven weeks of IMRT. Weekly doses were recalculated without replanning or with replanning to spare the PG. Sixty-three ART scenarios were simulated by considering all the combinations of numbers and timings of replanning. The PG cumulated doses corresponding to "standard" IMRT and ART scenarios were estimated and compared, either by calculating the average of weekly doses or using deformable image registration (DIR). RESULTS: Considering average weekly doses, the mean PG overdose using standard IMRT, compared to the planned dose, was 4.1Gy. The mean dosimetric benefit of 6 replannings was 3.3Gy. Replanning at weeks 1, 1-5, 1-2-5, 1-2-4-5 and 1-2-4-5-6 produced the lowest PG mean doses, 94% of the maximum benefit being obtained with 3 replannings. The percentage of patients who had a benefit superior to 5Gy for the contralateral PG was 31% for the three-replannings strategy. The same conclusions were found using DIR. CONCLUSION: Early replannings proved the most beneficial for PG sparing, three replannings (weeks 1-2-5), representing an attractive combination for ART in oropharyngeal cancer.
Authors: Molly M McCulloch; Choonik Lee; Benjamin S Rosen; Justin D Kamp; Chrissy M Lockhart; Jae Y Lee; Daniel F Polan; Peter G Hawkins; Carlos J R Anderson; Jolien Heukelom; Jan-Jakob Sonke; Clifton D Fuller; James M Balter; Randall K Ten Haken; Avraham Eisbruch; Kristy K Brock Journal: Pract Radiat Oncol Date: 2019-03-02
Authors: S B Lim; C J Tsai; Y Yu; P Greer; T Fuangrod; K Hwang; S Fontenla; F Coffman; N Lee; D M Lovelock Journal: Technol Cancer Res Treat Date: 2019-01-01