Abstract
In this study we analyzed prostate intrafraction motion during the course of stereotactic radiotherapy (STRT). STRT (5 fraction of 7.25Gy) was performed in 31 primary patients with prostate cancer. At least 3 gold fiducial markers were implanted in prostate of every patient 3-5 days before simulation. Prostate position on treatment table was verified with cone beam CT just before and immediately after the end of each radiotherapy session. This data help to determine prostate displacement in cranio-caudal, anterior-posterior and lateral axes. Average values of intra-fractional prostate displacement were as follows: 0,8+/-1,2mm - in cranio-caudal, 0.9+/-1,0mm - in lateral and 1.3+/-1,3mm - in anterior-posterior directions. In 5%-8,3% cases prostate displacement in cranio-caudal and lateral directions exceeded 2mm with maximal value of 5mm. In accordance with obtained average shifts we recommend following PTV margins: 1mm - in anterior-posterior and 3mm - in all other directions. In this case average intrafractional prostate shifts would not compromise dose delivery to prostate (V100 - 98%, D90 - 101%) and in comparison with standard (3mm, 5mm, 5mm, 5mm) margins would permit 16% reduction of rectum volume incorporated in 80% isodose. We propose that small average intrafractional displacement of prostate permits the use of narrower PTV margins without compromising coverage of the target and significant reduction of rectum volume covered by 80% isodose.References
Канаев С.В., Новиков С.Н., Ильин Н.Д. и др. Опыт использования биодеградирующих спейсеров при проведении стереотаксической лучевой терапии у больных раком предстательной железы // Сборник тезисов II Всероссийского съезда по радиохирургии и стереотаксической радиотерапии. 3-4 июня, СПб. -Инфра-М, Москва. - 2016. - C. 41-42.
Новиков С.Н., Канаев С.В., Новиков РВ. и др. Вы-сокодозная брахитерапия в лечении больных раком предстательной железы / Учебное пособие, Санкт-Петербург - СПб:Издательство ГБОУ ВПО СЗГМУ им. И.И. Мечникова, 2016. - 40 с.
Alongi F, Fiorentino A., De Bari B. SBRT and extreme hypofractionation: A new era in prostate cancer treatments? // Rep Pract Oncol Radiother. - 2015 - Vol. 20 - P. 411-416.
DAmbrosio D.J., Pollack A., Harris E.E. et al. Assessment of external beam radiation technology for dose escalation and normal tissue protection in the treatment of prostate cancer // Int. J Radiat Oncol Biol Phys. - 2008. - Vol. 70. - P 671-677.
Demanes D.J., Ghilezan M.I. High-dose-rate Brachytherapy as monotherapy for prostate cancer // Brachytherapy. -2014. - Vol. 13 - P. 529-541.
Gez E., Cytron S., Ben Yosef R. et al. Application of an interstitial and biodegradable balloon system for prostate-rectum separation during prostate cancer radiotherapy: a prospective multi-center study // Radiat Oncol. - 2013. - Vol. 8. - P. 96.
Gunnlaugsson A., Kjellen E., Hagberg O., Thellenberg-Karlsson C., Widmark A., Nilsson P. Change in prostate volume during extreme hypo-fractionation analysed with MRI // Radiat Oncol. - 2014. - Vol. 9. - P. 22.
Fuller D.B. Prostate stereotactic body radiotherapy -methods, rationale, outcomes, and future directions // Chapter in Stereotactic body therapy. A practical guide. A Gaya, Mahadeva A. Sprinfler-Verlag, London - 2015. - P. 195-224.
Hoskin P.J., Colombo A., Henry A. et al. GEC/ESTRO recommendations on high dose rate afterloading brachytherapy for localised prostate cancer: An update // Radiother. Oncol. - 2013. - Vol. 107. - Р 325-332.
Kim D.V.N., Straka C., L. Cho C., Timmerman R.D. Stereotactic body radiation therapy for prostate cancer: review of experience of a multicenter phase I/II dose-escalation study // Front Oncol. - 2014. - Vol. 26. - №4. - P 319.
Martinez A.A., Gonzalez J., Ye H., Ghilezan M., Shetty S., Kernen K., Gustafson G., Krauss D., Vicini F., Kestin L. Dose escalation improves cancer-related events at 10 years for intermediate- and high-risk prostate cancer patients treated with hypofractionated high-dose-rate boost and external beam radiotherapy // Int J Radiat Oncol Biol Phys. - 2011. - Vol. 79(2). - P. 363-370.
Skarsgard D., Cadman P., El-Gayed A., Pearcey R., Tai P., Pervez N., Wu J. Planning target volume margins for prostate radiotherapy using daily electronic portal imaging and implanted fiducial markers // Radiat Oncol. -2010. - Vol. 5. - P 52.
Stroom J.C., de Boer H.C., Huizenga H., Visser A.G. Inclusion of geometrical uncertainties in radiotherapy treatment planning by means of coverage probability // Int. J. Radiat. Oncol. Biol. Phys. - 1999. - Vol. 43(4). -P. 905-919.
van Herk M., Remeijer P, Rasch C., Lebesque J.V. The probability of correct target dosage: dose-population histograms for deriving treatment margins in radiotherapy // Int. J. Radiat. Oncol. Biol. Phys. - 2000. - Vol. 47(4). - P 1121-1135.
Viani G.A., Stefano E.J., Afonso S.L. Higher-than-conventional radiation doses in localized prostate cance r treatment: a meta-analysis of randomized, controlled trials // Int. J. Radiat. Oncol. Biol. Phys. - 2009. - Vol. 74(5). - P. 1405-1418.
Xie Y, Djajaputra D., King C.R. et al. Intrafractional motion of the prostate during hypofractionated radiotherapy // Int. J. Radiat. Oncol. Biol. Phys. - 2008. - Vol. 72(1). - P 236-246.
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