British Columbia Cancer Agency, Vancouver, BC, Canada.
Int J Radiat Oncol Biol Phys. 2010 Oct 1;78(2):415-21. doi: 10.1016/j.ijrobp.2009.07.1724. Epub 2010 Feb 3.
To evaluate the prostate-specific antigen (PSA) kinetics of PSA failure (PSAf) and PSA bounce (PSAb) after permanent (125)I prostate brachytherapy (PB).
The study included 1,006 consecutive low and "low tier" intermediate-risk patients treated with (125)I PB, with a potential minimum follow-up of 4 years. Patients who met the Phoenix definition of biochemical failure (nadir + 2 ng/mL(-1)) were identified. If the PSA subsequently fell to ≤0.5 ng/mL(-1)without intervention, this was considered a PSAb. All others were scored as true PSAf. Patient, tumor and dosimetric characteristics were compared between groups using the chi-square test and analysis of variance to evaluate factors associated with PSAf or PSAb.
Median follow-up was 54 months. Of the 1,006 men, 57 patients triggered the Phoenix definition of PSA failure, 32 (56%) were true PSAf, and 25 PSAb (44%). The median time to trigger nadir + 2 was 20.6 months (range, 6-36) vs. 49 mo (range, 12-83) for PSAb vs. PSAf groups (p < 0.001). The PSAb patients were significantly younger (p < 0.0001), had shorter time to reach the nadir (median 6 vs. 11.5 months, p = 0.001) and had a shorter PSA doubling time (p = 0.05). Men younger than age 70 who trigger nadir +2 PSA failure within 38 months of implant have an 80% likelihood of having PSAb and 20% chance of PSAf.
With adequate follow-up, 44% of PSA failures by the Phoenix definition in our cohort were found to be benign PSA bounces. Our study reinforces the need for adequate follow-up when reporting PB PSA outcomes, to ensure accurate estimates of treatment efficacy and to avoid unnecessary secondary interventions.
评估永久性（125）I 前列腺近距离放射治疗（PB）后前列腺特异性抗原（PSA）失败（PSAf）和 PSA 反弹（PSAb）的 PSA 动力学。
本研究纳入了 1006 例连续的低危和“低危分层”中危患者，均接受（125）I PB 治疗，随访时间至少为 4 年。根据 Phoenix 生化失败定义（最低点+2ng/ml）确定发生生化失败的患者。如果 PSA 随后降至≤0.5ng/ml（-1）且未进行干预，则认为是 PSAb。其他情况均被判定为真正的 PSAf。使用卡方检验和方差分析比较两组患者、肿瘤和剂量学特征，以评估与 PSAf 或 PSAb 相关的因素。
中位随访时间为 54 个月。在 1006 例患者中，57 例患者触发了 Phoenix 定义的 PSA 失败，其中 32 例（56%）为真正的 PSAf，25 例 PSAb（44%）。触发最低点+2 的中位时间为 20.6 个月（范围 6-36），而 PSAb 组和 PSAf 组分别为 49 个月（范围 12-83）（p<0.001）。PSAb 患者显著更年轻（p<0.0001），达到最低点的时间更短（中位数 6 个月 vs. 11.5 个月，p=0.001），PSA 倍增时间更短（p=0.05）。植入后 38 个月内触发最低点+2 PSA 失败且年龄<70 岁的男性，有 80%可能发生 PSAb，20%可能发生 PSAf。
在本队列中，根据 Phoenix 定义，44%的 PSA 失败被发现为良性 PSA 反弹。我们的研究强调了在报告 PB PSA 结果时需要进行充分的随访，以确保对治疗效果的准确估计，并避免不必要的二次干预。
