Raben Adam, Rusthoven Kyle E, Sarkar Abrihup, Glick Andrew, Benge Bruce, Jacobs Dayee, Raben David
Department of Radiation Oncology, Helen F. Graham Cancer Center, Wilmington, DE, USA.
Brachytherapy. 2009 Jul-Sep;8(3):297-303. doi: 10.1016/j.brachy.2008.12.004. Epub 2009 Feb 12.
Favorable dosimetric results have been reported using intraoperative inverse optimization (IO) for permanent prostate brachytherapy. The clinical implications of these improvements in dosimetry are unclear. We review toxicity and early biochemical outcomes for patients implanted using IO technique.
Between 2001 and 2007, 165 patients received permanent prostate implants using real-time IO and had >/=3 months of followup. Dose constraints for inverse planning were: the prostate volume receiving 100% of the prescription dose [prostate V(100)] was >95%; the dose received by 90% of the gland [prostate D(90)] was within the 140-180 by dose range; the volume of urethra receiving 150% of the prescription dose [urethra V(150)] was <30%; and the volume of rectal wall receiving 110% of the prescription dose [rectal V(110)] was <1.0 cc. Toxicity was prospectively scored using the Radiation Therapy Oncology Group toxicity scale and the International Prostate Symptom Score questionnaire. Biochemical control was determined using the nadir + 2 ng/mL definition.
Mean followup was 30 months (range, 6-63 months). Risk classification was low risk in 89% and intermediate risk in 11%. Iodine-125 sources were used for 161 implants and palladium-103 sources for four implants. The median number of seeds and total activity implanted were 61 and 999 MBq, respectively, for a median prostate volume of 33.6 cc. Late GU and GI morbidity was uncommon. Among patients with at least 24 months followup, 16% had persistent Grade 2-3 urinary morbidity. Grade 2 rectal bleeding occurred in 1 patient (0.6%). Biochemical failure has occurred in only 4 patients at last followup.
IO technique for prostate brachytherapy is associated with low rates of late morbidity and excellent early biochemical control. Additionally, the number of seeds and total implanted activity required to achieve a high-quality implant are lower compared with historical controls.
已有报道显示，术中逆向优化（IO）技术应用于前列腺近距离永久性植入治疗时可获得良好的剂量学结果。然而，这些剂量学改善的临床意义尚不清楚。我们回顾了采用IO技术植入患者的毒性反应和早期生化指标结果。
2001年至2007年间，165例患者接受了实时IO前列腺永久性植入治疗，并进行了≥3个月的随访。逆向计划的剂量限制为：接受100%处方剂量的前列腺体积[前列腺V(100)]＞95%；90%腺体接受的剂量[前列腺D(90)]在140 - 180 Gy剂量范围内；接受150%处方剂量的尿道体积[尿道V(150)]＜30%；接受110%处方剂量的直肠壁体积[直肠V(110)]＜1.0 cc。采用放射治疗肿瘤学组毒性量表和国际前列腺症状评分问卷对毒性反应进行前瞻性评分。使用最低点+ 2 ng/mL的定义确定生化控制情况。
平均随访时间为30个月（范围6 - 63个月）。风险分类为低危89%，中危11%。161例植入使用碘-125源，4例植入使用钯-103源。前列腺中位体积为33.6 cc时，植入种子数中位数和总活度分别为61粒和999 MBq。晚期泌尿生殖系统（GU）和胃肠道（GI）并发症并不常见。在至少随访24个月的患者中，16%有持续性2 - 3级泌尿系统并发症。1例患者（0.6%）出现2级直肠出血。最后一次随访时仅4例患者发生生化失败。
前列腺近距离治疗的IO技术与晚期并发症发生率低和早期生化控制良好相关。此外，与既往对照相比，实现高质量植入所需的种子数和总植入活度更低。
