Kestin Larry, Goldstein Neal, Vicini Frank, Yan Di, Korman Howard, Martinez Alvaro
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI 48073, USA.
Int J Radiat Oncol Biol Phys. 2002 Nov 1;54(3):686-97. doi: 10.1016/s0360-3016(02)03011-0.
When treating high-risk prostate cancer with radiation therapy, inclusion of the seminal vesicles (SVs) within the clinical target volume (CTV) can dramatically increase the volume of radiated normal tissues and hinder dose escalation. Because cancer may involve only the proximal portion of the frequently lengthy SVs, we performed a complete pathology review of prostatectomy specimens to determine the appropriate length of SV to include within the CTV when SV treatment is indicated.
A detailed pathologic analysis was performed for 344 radical prostatectomy specimens (1987-2000). All slides from each case were reviewed by a single pathologist (N.S.G.). Factors recorded for each case included length of each SV (cm), length of cancer involvement in each SV (cm) measured from the prostate-SV junction, and percentage of SV length involved.
Fifty-one patients (15%) demonstrated SV involvement in 81 SVs (21 unilateral, 30 bilateral SV involvement). The median SV length was 3.5 cm (range: 0.7-8.5 cm). Factors associated with SV involvement included the pretreatment PSA level, biopsy Gleason score, and clinical T classification. The commonly used risk group stratification was very effective at predicting SV positivity. Only 1% of low-risk patients (PSA <10 ng/mL, Gleason <or=6, and clinical stage <or=T2a) demonstrated SV involvement vs. 27% of high-risk patients. Patients with only one high-risk feature still demonstrated a 15% risk of SV involvement, whereas 58% of patients with all three high-risk features had positive SVs. The median length of SV involvement was 1.0 cm (90th percentile: 2.0 cm, range: 0.2-3.8 cm). A median of 25% of each SV was involved with adenocarcinoma (90th percentile: 54%, range: 4%-75%). For the 81 positive SVs, no factor was associated with a greater length or percentage of SV involvement. In the entire population, 7% had SV involvement beyond 1.0 cm. There was an approximate 1% risk of SV involvement beyond 2.0 cm or 60% of the SV. In addition, this risk was less than 4% for all subgroups, including high-risk patients.
A portion of the SV should be included in the CTV only for higher-risk patients (PSA >or=10 ng/mL, biopsy Gleason >or=7, or clinical T stage >or=T2b). When treating the SV for prostate cancer, only the proximal 2.0-2.5 cm (approximately 60%) of the SV should be included within the CTV.
在用放射治疗高危前列腺癌时，将精囊（SVs）纳入临床靶区（CTV）会显著增加正常组织的受照体积，并阻碍剂量提升。由于癌症可能仅累及通常较长的精囊的近端部分，我们对前列腺切除标本进行了全面的病理检查，以确定在需要对精囊进行治疗时，应纳入CTV的精囊合适长度。
对344例根治性前列腺切除标本（1987 - 2000年）进行了详细的病理分析。每例的所有切片均由同一位病理学家（N.S.G.）复查。记录的每例因素包括每个精囊的长度（厘米）、从前列腺 - 精囊交界处测量的每个精囊中癌累及的长度（厘米）以及精囊长度累及的百分比。
51例患者（15%）的81个精囊中发现有癌累及（21个单侧、30个双侧精囊累及）。精囊的中位长度为3.5厘米（范围：0.7 - 8.5厘米）。与精囊累及相关的因素包括治疗前前列腺特异抗原（PSA）水平、活检Gleason评分和临床T分期。常用的风险组分层在预测精囊阳性方面非常有效。低风险患者（PSA <10 ng/mL，Gleason≤6，临床分期≤T2a）中只有1%的患者精囊有累及，而高风险患者中这一比例为27%。仅有一项高风险特征的患者精囊累及风险仍为15%，而具有所有三项高风险特征的患者中58%精囊为阳性。精囊累及的中位长度为1.0厘米（第90百分位数：2.0厘米，范围：0.2 - 3.8厘米）。每个精囊腺癌累及的中位比例为25%（第90百分位数：54%，范围：4% - 75%）。对于81个阳性精囊，没有因素与更长的精囊累及长度或更高的精囊累及比例相关。在整个研究人群中，7%的患者精囊累及超过1.0厘米。精囊累及超过2.0厘米或超过精囊60%的风险约为1%。此外，所有亚组（包括高风险患者）的这一风险均小于4%。
仅对于更高风险的患者（PSA≥10 ng/mL，活检Gleason≥7，或临床T分期≥T2b），应将部分精囊纳入CTV。在对前列腺癌的精囊进行治疗时，CTV中应仅纳入精囊近端的2.0 - 2.5厘米（约60%）。
