Fonteyne Valérie, Sadeghi Simin, Ost Piet, Vanpachtenbeke Frank, Vuye Philippe, Lumen Nicolaas, De Meerleer Gert
Ghent University Hospital, Department of Radiation Oncology and Experimental Cancer Research , Belgium.
Acta Oncol. 2015 Jun;54(6):854-61. doi: 10.3109/0284186X.2014.974826. Epub 2014 Nov 11.
External beam radiotherapy is an excellent treatment for patients with prostate cancer (PC). Assessing long-term radiotherapy-induced toxicity is important. We evaluated the impact of implementing different rectal dose volume constraints (DVC) on late rectal and urinary toxicity.
Six hundred and thirty-seven PC patients were treated with high-dose intensity-modulated radiotherapy (IMRT) in the primary (median dose of 78 Gy to the prostate) or postoperative setting [median dose of 74 (adjuvant) and 76 Gy (salvage) to the prostatic bed]. Three groups were defined according to different DVC applied over time. The incidence of late rectal and urinary toxicity was evaluated. Three-year actuarial risk estimations of grade 2-3 rectal and urinary toxicity were calculated (Kaplan-Meier statistics).
Median follow-up was five years. Overall, the incidence of late grade 3 and 2 rectal toxicity was 1% and 11%. The calculated three-year actuarial risk of developing late grade≥2 rectal toxicity decreased from 16% to 7% and 5% for patients in Group 1, Group 2 and Group 3, respectively (p<0.001). Respectively, 17 (4%) and 98 (24%) patients developed grade 3 and 2 late urinary toxicity in the primary setting. In the postoperative setting, 15 (6%) and 62 (26%) patients developed grade 3 and 2 urinary toxicity, respectively. The three-year actuarial risk of developing late≥grade 2 urinary toxicity in primary- and postoperative-treated patients was 22% and 23%, respectively. This was not significantly different between the three groups.
The majority of patients developed no or only moderate rectal toxicity after high-dose IMRT for PC. Implementing different rectal DVC resulted in a significant decrease of late rectal toxicity without affecting urinary toxicity.
外照射放疗是前列腺癌（PC）患者的一种有效治疗方法。评估长期放疗引起的毒性很重要。我们评估了实施不同的直肠剂量体积限制（DVC）对晚期直肠和泌尿系统毒性的影响。
637例PC患者在初次治疗（前列腺中位剂量78 Gy）或术后治疗（前列腺床中位剂量74 Gy（辅助治疗）和76 Gy（挽救治疗））中接受了高剂量调强放疗（IMRT）。根据不同时期应用的DVC定义了三组。评估晚期直肠和泌尿系统毒性的发生率。计算2-3级直肠和泌尿系统毒性的三年精算风险估计值（Kaplan-Meier统计）。
中位随访时间为五年。总体而言，晚期3级和2级直肠毒性的发生率分别为1%和11%。计算得出，第1组、第2组和第3组患者发生晚期≥2级直肠毒性的三年精算风险分别从16%降至7%和5%（p<0.001）。在初次治疗中，分别有17例（4%）和98例（24%）患者发生3级和2级晚期泌尿系统毒性。在术后治疗中，分别有15例（6%）和62例（26%）患者发生3级和2级泌尿系统毒性。初次治疗和术后治疗患者发生晚期≥2级泌尿系统毒性的三年精算风险分别为22%和23%。三组之间无显著差异。
大多数PC患者在接受高剂量IMRT后未发生或仅发生中度直肠毒性。实施不同的直肠DVC可显著降低晚期直肠毒性，且不影响泌尿系统毒性。
