Iwama Kazuki, Yamazaki Hideya, Shimizu Daisuke, Suzuki Gen, Nakamura Satoaki, Sasaki Naomi, Takeneka Tadashi, Okabe Haruumi, Nishikawa Tatsuyuki, Yoshida Ken
Department of Radiology, Ujitakeda Hospital, Uji, Japan.
Department of Radiology, Ujitakeda Hospital, Uji, Japan
Anticancer Res. 2017 Oct;37(10):5755-5760. doi: 10.21873/anticanres.12015.
To investigate the correlation between frequency of action level of interfractional rectal displacement requiring repeated precaution in patients with prostate cancer and late toxicity from image-guided intensity-modulated radiation therapy (IG-IMRT) using helical tomotherapy.
We examined 264 patients who underwent IG-IMRT during 2007-2011. Megavoltage computed tomographic (MVCT) images were acquired before radiation therapy and was examined with soft-tissue matching by comparing treatment planning images within 9,345 fractions. Displacement of the anterior rectal region larger than 5 mm, requiring repeated precaution, was defined as the level of rectal displacement requiring action (ARD).
ARD was identified in 815 (7.7%) out of 9,345 fractions and at least once in 82% (216/264) of patients. The highest incidence of ARD (11%) was found during the initial week of treatment (first five and next five fractions), after which the incidence decreased to 6% (p<0.0001). Patients with lean body (lower body mass index (BMI) tended to have a higher incidence of ARD. We identified 16 (6%) cases of gastrointestinal toxicity and 12 (4.5%) genitourinary toxicities as a late adverse reaction (3 months or later after IG-IMRT). There was no correlation between ARD and late toxicity. Prostate-specific antigen (PSA) control was also similar (p=0.12) between those with ARD (96% at 5 year) and those without ARD (88%).
ARD occurred predominantly in lean patients, during the initial week of treatment and became less likely over time. ARD was not correlated to late toxicity and PSA control, therefore, IG-IMRT technique was able to adequately control error due to interfractional prostate and rectal motion.
探讨前列腺癌患者中因分次间直肠移位达到需反复采取预防措施的行动水平的频率与采用螺旋断层放疗的影像引导调强放疗（IG-IMRT）所致晚期毒性之间的相关性。
我们检查了2007年至2011年期间接受IG-IMRT的264例患者。在放疗前采集兆伏级计算机断层扫描（MVCT）图像，并通过比较9345次分次治疗计划图像进行软组织匹配检查。前直肠区域移位大于5 mm且需反复采取预防措施被定义为需采取行动的直肠移位水平（ARD）。
在9345次分次中，815次（7.7%）出现ARD，82%（216/264）的患者至少出现过一次ARD。ARD发生率最高（11%）出现在治疗的第一周（最初五次和接下来五次分次），此后发生率降至6%（p<0.0001）。体型偏瘦（较低体重指数（BMI））的患者ARD发生率往往更高。我们将16例（6%）胃肠道毒性和12例（4.5%）泌尿生殖系统毒性确定为晚期不良反应（IG-IMRT后3个月或更晚）。ARD与晚期毒性之间无相关性。有ARD的患者（5年时为96%）和无ARD的患者（88%）之间前列腺特异性抗原（PSA）控制情况也相似（p=0.12）。
ARD主要发生在体型偏瘦的患者中，在治疗的第一周出现，且随着时间推移发生的可能性降低。ARD与晚期毒性及PSA控制无关，因此，IG-IMRT技术能够充分控制因分次间前列腺和直肠运动导致的误差。
