Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
Int J Radiat Oncol Biol Phys. 2012 Sep 1;84(1):125-9. doi: 10.1016/j.ijrobp.2011.11.047. Epub 2012 Feb 11.
To compare toxicity profiles and biochemical tumor control outcomes between patients treated with high-dose image-guided radiotherapy (IGRT) and high-dose intensity-modulated radiotherapy (IMRT) for clinically localized prostate cancer.
Between 2008 and 2009, 186 patients with prostate cancer were treated with IGRT to a dose of 86.4 Gy with daily correction of the target position based on kilovoltage imaging of implanted prostatic fiducial markers. This group of patients was retrospectively compared with a similar cohort of 190 patients who were treated between 2006 and 2007 with IMRT to the same prescription dose without, however, implanted fiducial markers in place (non-IGRT). The median follow-up time was 2.8 years (range, 2-6 years).
A significant reduction in late urinary toxicity was observed for IGRT patients compared with the non-IGRT patients. The 3-year likelihood of grade 2 and higher urinary toxicity for the IGRT and non-IGRT cohorts were 10.4% and 20.0%, respectively (p = 0.02). Multivariate analysis identifying predictors for grade 2 or higher late urinary toxicity demonstrated that, in addition to the baseline Internatinoal Prostate Symptom Score, IGRT was associated with significantly less late urinary toxicity compared with non-IGRT. The incidence of grade 2 and higher rectal toxicity was low for both treatment groups (1.0% and 1.6%, respectively; p = 0.81). No differences in prostate-specific antigen relapse-free survival outcomes were observed for low- and intermediate-risk patients when treated with IGRT and non-IGRT. For high-risk patients, a significant improvement was observed at 3 years for patients treated with IGRT compared with non-IGRT.
IGRT is associated with an improvement in biochemical tumor control among high-risk patients and a lower rate of late urinary toxicity compared with high-dose IMRT. These data suggest that, for definitive radiotherapy, the placement of fiducial markers and daily tracking of target positioning may represent the preferred mode of external-beam radiotherapy delivery for the treatment of prostate cancer.
比较高剂量图像引导放疗（IGRT）和高剂量强度调制放疗（IMRT）治疗局限性前列腺癌患者的毒性谱和生化肿瘤控制结果。
2008 年至 2009 年间，186 例前列腺癌患者接受 IGRT 治疗，剂量为 86.4 Gy，每天根据植入前列腺基准标记物的千伏成像校正靶区位置。该组患者与 2006 年至 2007 年间接受相同处方剂量、但未植入基准标记物的类似队列（非 IGRT）进行回顾性比较。中位随访时间为 2.8 年（范围 2-6 年）。
与非 IGRT 患者相比，IGRT 患者的晚期尿毒性显著降低。IGRT 和非 IGRT 队列的 3 年 2 级及以上尿毒性发生率分别为 10.4%和 20.0%（p=0.02）。多变量分析确定 2 级或更高晚期尿毒性的预测因素表明，除了基线国际前列腺症状评分外，IGRT 与非 IGRT 相比，与较低的晚期尿毒性显著相关。两组治疗的 2 级及以上直肠毒性发生率均较低（分别为 1.0%和 1.6%；p=0.81）。对于低危和中危患者，IGRT 和非 IGRT 治疗的前列腺特异性抗原无复发生存率结果无差异。对于高危患者，IGRT 治疗组与非 IGRT 治疗组相比，3 年时观察到生化肿瘤控制显著改善。
与高剂量 IMRT 相比，IGRT 可改善高危患者的生化肿瘤控制，并降低晚期尿毒性发生率。这些数据表明，对于根治性放疗，植入基准标记物和每天跟踪靶区定位可能代表前列腺癌外照射治疗的首选模式。
