Khalifa J, Commandeur F, Bachaud J-M, de Crevoisier R
Département de radiothérapie, institut Claudius-Régaud, 20-24, rue du Pont-Saint-Pierre, 31052 Toulouse, France.
Cancer Radiother. 2013 Oct;17(5-6):461-9. doi: 10.1016/j.canrad.2013.06.031. Epub 2013 Aug 20.
The planning CT allows the delineation of the prostate (clinical target volume, CTV) but with an imprecision at the apex and the inability to visualize the intraprostatic cancer. MRI enables accurate visualization of the prostate outlines and in some extent the intraprostatic tumour (gross tumour volume [GTV]). The integration of MRI data within the CT remains still complex. Analysis of prostatectomy specimen has guided the definition of a CTV beyond the capsule, depending on pretreatment factors. In practice, the CTV can be defined as follows: prostate-only, for good prognosis tumours; prostate (+0 to 5mm margins, excluding the rectum) and seminal vesicles (possibly limited to 2 cm of their proximal region) for intermediate-risk tumours; prostate (+5mm margins) and seminal vesicles for high-risk tumours. The planning target volume (PTV) should be between 5mm and 10mm depending on the space directions, in the absence of image-guidance (IGRT). It could be reduced to 5mm in case of IGRT. In the adjuvant setting after prostatectomy, the definition of the CTV should follow the recommendations from cooperative groups. It takes into account both the analysis of pattern of local recurrence after prostatectomy, but also the specific histological analysis of the surgical specimen of the patient. The corresponding PTV margin is 6 to 8mm.
计划CT可勾勒出前列腺（临床靶区，CTV），但在前列腺尖部存在不精确性，且无法显示前列腺内的癌灶。MRI能够准确显示前列腺轮廓，并在一定程度上显示前列腺内肿瘤（大体肿瘤体积[GTV]）。将MRI数据整合到CT中仍然很复杂。前列腺切除标本的分析根据术前因素指导了超出包膜的CTV的定义。在实践中，CTV可定义如下：对于预后良好的肿瘤，仅为前列腺；对于中危肿瘤，为前列腺（+0至5mm边缘，不包括直肠）和精囊（可能仅限于其近端2cm区域）；对于高危肿瘤，为前列腺（+5mm边缘）和精囊。在没有图像引导（IGRT）的情况下，计划靶区（PTV）应根据空间方向在5mm至10mm之间。如果采用IGRT，可减至5mm。在前列腺切除术后的辅助治疗中，CTV的定义应遵循协作组的建议。这既要考虑前列腺切除术后局部复发模式的分析，也要考虑患者手术标本的特定组织学分析。相应的PTV边缘为6至8mm。
