Ebook Prostate cancer - Diagnosis and clinical management: Part 2
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Ebook Prostate cancer - Diagnosis and clinical management: Part 2
CHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2llege London. Mount Vernon Cancer Centre. Northwood, UKIntroductionRadiation is one of die principal treatment modalities for prostate cancer [1,2]. Since the early twentieth century, radiation has been used lo treat all stages of the disease. In 1904, Armand and Léon Imbert were the first clinician Ebook Prostate cancer - Diagnosis and clinical management: Part 2s to report on the successful use of X-ray therapy to treat an advanced prostate cancer (3Ị. In 1908, both Minet and Desnos used radium-containing catEbook Prostate cancer - Diagnosis and clinical management: Part 2
heters to deliver an early form of brachytherapy, and in 1923 Waters and Pierson used "deep" X-rays to treat a prostate cancer bony metastasis [4-7]. CHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2uter technology. Now in the twenty-first century, practitioners of prostate cancer radiation therapy can tailor their treatments to the stage and needs of the patient.External beam radiotherapyThe first attempts to use X-rays to treat prostate cancer relied upon low-energy beams. Compared lo modern Ebook Prostate cancer - Diagnosis and clinical management: Part 2mega voltage X-rays, they lacked the comparative depth of penetrance and consequently led to high-radiation doses at the patient's skin surface. ThisEbook Prostate cancer - Diagnosis and clinical management: Part 2
meant early prostate cancer patients suffered significant acute skin toxicity and an increased risk of radiation-induced skin cancers. Due to these eaCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2te Cancer: Diagnosis and Clinical Management, First Edition.Edited by Ashutosh K. Tewari, Peter Whelan and John D. Graham.©2014 John Wiley tý Sons, Ltd. Published 2014 by John Wiley &• Sons, Lid.170Radiation Therapy in the Management of Prostate Cancer 171Prior to World War ll important discoveries Ebook Prostate cancer - Diagnosis and clinical management: Part 2were made in radiation science that led to new developments in radiotherapy. The work of Led Szilard. Rolf Widcroe, and Gustav Ising during the 1920sEbook Prostate cancer - Diagnosis and clinical management: Part 2
led to subatomic particle acceleration theory and the creation of particle accelerators termed linear accelerators or "linacs" [8,9]. These new machinCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2 lying beneath the skin surface to receive higher doses of radiation without the high levels of surface toxicity seen previously with lower-energy electron beams. In 1953, an 8-megavoltagc (MV) linac was installed in the Hammersmith Hospital in London, which was the first to begin treating patients Ebook Prostate cancer - Diagnosis and clinical management: Part 2with various tumors [10]. This achievement was to herald a new age in external beam radiotherapy (EBRT).Over the next 50 years F.BRT underwent furtherEbook Prostate cancer - Diagnosis and clinical management: Part 2
refinement through the discovery of X-ray computed tomography (CT) and advances in linear accelerator design and technology. Up until the early 1990sCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2echnique meant that the patient's prostate gland and a significant portion of their surrounding pelvis were encompassed within a typically box-shaped radiation field. Due to the uncertainties of tumor location and organ movement, shielding of normal tissue was relatively minimal. This of course mean Ebook Prostate cancer - Diagnosis and clinical management: Part 2t that the volume of normal tissue treated was great and that patients often developed significant acute gastrointestinal (GI) and genitourinary (GU)Ebook Prostate cancer - Diagnosis and clinical management: Part 2
toxicitics 1111. Because of these toxicities patients were often unable to tolerate radiotherapy doses in excess of 67-70 Gy when delivered using convCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2onal conformal radiotherapy (3D-CRT) [12,13]. This term describes how the linear accelerator performs complex beam shaping to conform the X-rays to match the outline of the patient's tumor on the patient's treatment planning scan. Conforming the beams also helps minimize the dose of radiation delive Ebook Prostate cancer - Diagnosis and clinical management: Part 2red to the patient's normal pelvic organs (Figure 9.1) [ 14]. A phase III randomized controlled trial comparing this technique with conventional radioEbook Prostate cancer - Diagnosis and clinical management: Part 2
therapy’ using a standard dose of 64 Gy has shown a significant reduction in the dose-limiting late side effect of proctitis with no impact on diseaseCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2intensity-modulated172 Chapter 9Figure 9.1 Top three images represent the isodose distributions from a conventional radiotherapy plan and the bottom three images represent the isodose distribution from a ĨD-CRT prostate plan. The arrows indicate beam direction, (a) CT-scan slice at the level of the Ebook Prostate cancer - Diagnosis and clinical management: Part 2seminal vesicles: (b) CT-scan slice through mid-prostate: (C) CT-scan slice through the prostate above the apex. The 78, 77, 70, 55, 45, and 25 Gy linEbook Prostate cancer - Diagnosis and clinical management: Part 2
es arc shown 114|. Reproduced from Reference 14 with permission from Elsevier.radiotherapy" (IMRT). With IMRT radiation, physicists are able to plan mCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2achieved (Figure 9.2, Plate 9.2). The adoption of IMRT and inverse planning techniques has allowed clinicians to increase the dose delivered to the prostate gland while maintaining acceptably low doses of radiation Io the patient's normal pelvic organs and GI tract 116, 17]. 3D-CRT and now IMRT have Ebook Prostate cancer - Diagnosis and clinical management: Part 2 helped to reduce the incidence of GI and GƯ late toxicity commonly seen with early conventional radiotherapy. These new radiotherapy treatment techniEbook Prostate cancer - Diagnosis and clinical management: Part 2
ques have permitted further studies to safely investigate the potential benefits of radiotherapy dose escalation to the prostate gland and pelvic lympCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2 trial utilized 3D-CRT or IMRT and studied radiation doses ranging from the original conventional dose of 64 Gy up to a dose of 86 Gy. Studies from The Royal Marsden Hospital (RMII), MRC RT01, MD Anderson, and the Dutch mullicenier trial reported improvements in overall PSA control of between 6% and Ebook Prostate cancer - Diagnosis and clinical management: Part 2Radiation Therapy in the Management of Prostate Cancer 173Figure 9.2 The top left and bottom two images represent the color wash dose distributions frEbook Prostate cancer - Diagnosis and clinical management: Part 2
om an IMRT prostate and pelvic lymph node radiotherapy plan. The top right image shows the corresponding dose-volume histogram for the plan. Note the CHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2iation [18-21]. The RMH pilot study and MRC RT01 trial compared 64 Gy with 74 Gy, the MD Anderson compared 70 Gy with 78 Gy, and the Dutch trial compared 68 Gy with 78 Gy [ 18-211. More recently, Kuban el al. has published an updated analysis on the longterm outcomes of the MD Anderson dose escalati Ebook Prostate cancer - Diagnosis and clinical management: Part 2on trial; 301 patients with stage Tib to T3 prostate cancer [22]. They reported superior freedom from biochemical or clinical failure in the group ranEbook Prostate cancer - Diagnosis and clinical management: Part 2
domized to 78 Gy compared with 70 Gy (78% vs. 59%, p = .004) after a median follow-up of 8.7 years. In light of these findings, the conventional dose CHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2isk cancers. Intermediate- and high-risk prostate cancer patients should receive doses up to 81 Gy 116, 23, 241.Despite the advantages of dose escalation on disease control, it should be noted that dose escalation does come with the risk of increased GI and GU toxicity. The MRC RT01 (rial showed tha Ebook Prostate cancer - Diagnosis and clinical management: Part 2t patients treated in the dose-escalated conformal arm had higher rates of late grade 2 or above GI toxicity (24%), reflecting a major increase in ureEbook Prostate cancer - Diagnosis and clinical management: Part 2
thral stricture rate, and GU (11%) toxicity compared with those in the conventional arm (8% and 24%, respectively) 119]. Sexual function assessment inCHAPTER 9Radiation Therapy in theManagement of Prostate CancerJ. Conibear1 and P.J. ĩỉoskin2‘Muuul Vernon Cancer Centre. Middlesex. UK2 University Col Ebook Prostate cancer - Diagnosis and clinical management: Part 2xual dysfunction.Androgen deprivation therapy and nodal irradiationPatients with locally advanced T3 prostate cancers have a high risk ot pelvic-lymph node involvement. As a consequence, in historical scries they have relatively- poor disease-free survival rales; only 22.5% (95% CI = 19-26) al 10 ye Ebook Prostate cancer - Diagnosis and clinical management: Part 2ars |25|. In the United Kingdom, approximately one-third ot newly diagnosed patients present with T3 disease and the majority of them arc suitable forEbook Prostate cancer - Diagnosis and clinical management: Part 2
radiotherapy given with curative intent [26]. Normally these patients are now treated with a combination of EBRT and androgen deprivation therapy (AIGọi ngay
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