Department of Radiation Oncology, University Hospital of Liège, Belgium.
Radiother Oncol. 2010 Dec;97(3):462-6. doi: 10.1016/j.radonc.2010.06.006. Epub 2010 Aug 17.
To calculate the α/β of prostate adenocarcinoma.
From January 1997 to December 2005, 328 patients were treated consecutively with external beam radiotherapy and brachytherapy boost. The patients with at least one of the following adverse prognostic factors were included: PSA>10 ng/ml, Gleason score ≥7, T≥2B. A total EQD2 of 80 Gy was delivered uniformly within the same timeframe. Prior to August 2002, the patients were treated to low-dose-rate brachytherapy using (192)Ir (n=201), and those treated thereafter received a high-dose-rate brachytherapy boost (n=127). The equivalency of dose was established using the incomplete repair model, with generally accepted α/β ratio of 3 Gy, and half-time for repair of sublethal damage (HTR) of 1.5h.
In a Cox proportional hazards model, the two groups displayed no difference (HR: 0.99, 95% CI: 0.87-1.1, p=0.98) in biochemical control. Analyzing using the linear quadratic model, the data fit well an α/β ratio of 3.41 Gy (95% CI: 2.56-4.26) and the recently published HTR of 1.9 h (95% CI: 1.4-2.4), but also an α/β of 5.87 Gy (95% CI: 4.67-7.07) and the more widely established HTR of 1.5 h.
Unlike the previously published data, calculation of the α/β ratio from consecutive patients and using a uniform treatment duration points to higher values than 2.5 Gy.
计算前列腺腺癌的α/β值。
1997 年 1 月至 2005 年 12 月，328 例患者连续接受外照射放疗和近距离放疗加量治疗。纳入标准为：PSA>10ng/ml、Gleason 评分≥7、T≥2B。所有患者在同一时间段内均接受了总剂量 80Gy 的等剂量放疗。2002 年 8 月前，201 例患者接受低剂量率（192）Ir 近距离放疗治疗，此后 127 例患者接受高剂量率近距离放疗加量治疗。采用不完全修复模型，用公认的 3Gy 的α/β比值和 1.5h 的亚致死损伤修复半衰期（HTR）来建立剂量等效性。
在 Cox 比例风险模型中，两组患者的生化控制无差异（HR：0.99，95%CI：0.87-1.1，p=0.98）。采用线性二次模型分析，数据拟合较好的α/β比值为 3.41Gy（95%CI：2.56-4.26）和最近发表的 HTR 值为 1.9h（95%CI：1.4-2.4），但也符合 α/β比值为 5.87Gy（95%CI：4.67-7.07）和更为广泛接受的 HTR 值为 1.5h。
与之前发表的数据不同，从连续患者中计算α/β比值并使用统一的治疗持续时间会得出高于 2.5Gy 的值。
