Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
Int J Radiat Oncol Biol Phys. 2010 May 1;77(1):131-8. doi: 10.1016/j.ijrobp.2009.04.040. Epub 2009 Dec 11.
For prostate cancer patients at risk for subclinical spread of the disease, we investigated whether incidental dose outside the target was associated with tumor control.
We selected 352 intermediate-risk (mainly T2b-T3a) and high-risk (mainly T3b) patients treated in a randomized trial. Target volume was prostate (68-78 Gy) and seminal vesicles (50-78 Gy). Failure (clinical or biochemical) was evaluated at 4 years. To compare three-dimensional dose distributions, an automated mapping procedure was introduced. Between patients, these maps provide an approximate identification of corresponding anatomical locations. Maps of the dose difference between patients with and without failure were constructed. Univariate and multivariate analyses were performed including the dose in selected points.
Dose differences were mainly found in the obturatorial region for the high-risk patients, and in the presacral region for the intermediate risk group (>7 Gy, p < 0.01). Univariate hazard ratios per 10 Gy for selected dose points were 0.83 (p = 0.01, obturatorial) and 0.72 (p = 0.002, presacral). These hazard ratios were stable under multivariate analysis correcting for established prognostic factors, hospital, and dose to the prostate.
Patients without failure have received on average a higher dose to regions where regional cancer spread could be expected.
对于患有疾病亚临床扩散风险的前列腺癌患者，我们研究了靶区外偶然剂量是否与肿瘤控制有关。
我们选择了 352 名处于中危（主要为 T2b-T3a）和高危（主要为 T3b）的随机试验治疗的患者。靶区为前列腺（68-78Gy）和精囊（50-78Gy）。在 4 年内评估失败（临床或生化）。为了比较三维剂量分布，引入了自动映射程序。在患者之间，这些图谱提供了对应解剖位置的近似标识。构建了有失败和无失败患者之间的剂量差异图谱。进行了单变量和多变量分析，包括选定点的剂量。
高危患者的剂量差异主要发生在闭孔区域，中危组的剂量差异主要发生在骶前区域（>7Gy，p<0.01）。对于选定的剂量点，每 10Gy 的单变量危险比为 0.83（p=0.01，闭孔）和 0.72（p=0.002，骶前）。在多变量分析中，校正了既定的预后因素、医院和前列腺剂量后，这些危险比仍然稳定。
无失败患者的靶区外区域平均接受了更高的剂量，这些区域可能会出现区域性癌症扩散。
