Samper Pilar M, López Carrizosa M Concepción, Pérez Casas Ana, Vallejo Carmen, Rubio Rodríguez M Carmen, Pérez Vara Consuelo, Melchor Iñiguez Miguel
Department of Radiation Oncology, Hospital Central de la Defensa, Madrid, Spain.
Clin Transl Oncol. 2006 Aug;8(8):599-605. doi: 10.1007/s12094-006-0066-0.
Prostate volume involves a defined toxicity predictor in the radiation therapy of localized prostate cancer. Neoadjuvant hormone therapy (nHT) can reduce prostate volume and, therefore, the planned volume. The objective of this study was to establish if the value of nHT reduces the planned volume and if this reduction correlates with a reduction of the dose received in the target organs.
28 patients diagnosed of localized prostate cancer and referred to our departments for radiation therapy with radical intention, in the period ranging between April 2002 and October 2003, were included prospectively. The patients received nHT (triptorelin + flutamide) for 2 months and adjuvant HT until completing 2 years in the high-risk cases. A transrectal ultrasound study was performed in all patients, simulation CT and planning before the start of HT and after 2 months of treatment. The radiation therapy was carried out with 6 or 18 MV LINAC photons, with a dose fractioning scheme of 5 x 180-200 cGy, a total dosage of 66-72 Gy to prostate, 56 Gy to seminal vesicles and, in the high-risk cases, 46 Gy to pelvic lymph nodes.
The distribution according to risk group was: low risk 3.6%, intermediate risk 28.6% and high risk 67.9%. By transrectal ultrasound, prostate volume on diagnosis was 50.65 cc pre HT and 38.97 cc post HT (p < 0.001), which means a volume reduction of 24%. The comparative analysis of the dose-volume histograms of the first versus the second CT shows a reduction in the planned volume GTV1 (prostate) (81.33 cc vs 63.96 cc, p < 0.05), PTV1 (prostate and margin) (197.51 cc vs 168.38 cc, p < 0.001) and PTV2 (prostate, vesicles and margin) (340.5 cc vs 307.26 cc, p < 0.05), a reduction of the maximum dose in the seminal vesicles (70.2 versus 68.75 Gy, p < 0.05), a reduction of the mean dose in the seminal vesicles (65.07 Gy versus 63.07 Gy, p < 0.05), PTV2 (67.72 Gy versus 66.9 Gy, p < 0.01) and PTV3 (prostate, vesicles, pelvic lymph nodes and margin) (58.86 Gy versus 57.21 Gy, p < 0.01), a reduction of the D90 in the seminal vesicles (61.83 Gy versus 60.06 Gy, p < 0.05) and PTV2 (61.04 Gy versus 59.45 Gy, p < 0.05) and a reduction of V60 of the rectum (32.45% versus 28.22%, p < 0.05) and V60 of the bladder (41.78% versus 31.67%, p < 0.005).
Neoadjuvant hormone therapy reduces significantly prostate volume and as a result the planned volume and consequently the rectal and bladder V60 can be significantly reduced.
在局限性前列腺癌的放射治疗中，前列腺体积是一个明确的毒性预测指标。新辅助激素治疗（nHT）可减小前列腺体积，进而减小计划靶体积。本研究的目的是确定nHT是否能减小计划靶体积，以及这种减小是否与靶器官所接受剂量的减少相关。
前瞻性纳入了28例2002年4月至2003年10月期间被诊断为局限性前列腺癌并因根治性目的转诊至我院接受放射治疗的患者。患者接受nHT（曲普瑞林+氟他胺）治疗2个月，高危病例辅助激素治疗直至满2年。所有患者在HT开始前及治疗2个月后均进行了经直肠超声检查、模拟CT及计划制定。放射治疗采用6或18MV直线加速器光子，剂量分割方案为5×180 - 200cGy，前列腺总剂量66 - 72Gy，精囊56Gy，高危病例盆腔淋巴结46Gy。
根据风险组分布为：低危3.6%，中危28.6%，高危67.9%。经直肠超声检查显示，诊断时前列腺体积HT前为50.65cc，HT后为38.97cc（p < 0.001），即体积减小了24%。首次与第二次CT的剂量体积直方图对比分析显示，计划靶体积GTV1（前列腺）减小（81.33cc对63.96cc，p < 0.05），PTV1（前列腺及边缘）减小（197.51cc对168.38cc，p < 0.001），PTV2（前列腺、精囊及边缘）减小（340.5cc对307.26cc，p < 0.05），精囊最大剂量减小（70.2对68.75Gy，p < 0.05），精囊平均剂量减小（65.07Gy对63.07Gy，p < 0.05），PTV2（67.72Gy对66.9Gy，p < 0.01），PTV3（前列腺、精囊、盆腔淋巴结及边缘）（58.86Gy对57.21Gy，p < 0.01），精囊D90减小（61.83Gy对60.06Gy，p < 0.05），PTV2（61.04Gy对59.45Gy，p < 0.05），直肠V60减小（32.45%对28.22%，p < 0.05），膀胱V60减小（41.78%对31.67%，p < 0.005）。
新辅助激素治疗可显著减小前列腺体积，从而减小计划靶体积，进而可显著降低直肠和膀胱的V60。
