Diaz A, Roach M, Marquez C, Coleman L, Pickett B, Wolfe J S, Carroll P, Narayan P
Department of Radiation Oncology, University of California, San Francisco 94143-0226.
Int J Radiat Oncol Biol Phys. 1994 Sep 30;30(2):323-9. doi: 10.1016/0360-3016(94)90011-6.
To evaluate the use of pretreatment prostate specific antigen, Gleason score, and clinical stage as predictors of the risk of seminal vesicle involvement in patients with clinically localized prostatic cancer, and to determine the impact of excluding the seminal vesicles on the dose received by surrounding normal tissues.
An empirically derived equation combining the preoperative prostate specific antigen and Gleason score was applied to 188 patients treated with radical prostatectomy, for whom pathologic evaluation of the seminal vesicles was available. High and low risk groups for seminal vesicle involvement were defined using this equation. The observed risks of seminal vesicle involvement was compared to the predicted risk using the preoperative prostate specific antigen, Gleason score or clinical stage alone or using the empirical equation. Dose-volume histograms for five patients treated using six-field conformal radiotherapy were compared including and excluding the seminal vesicles.
Using the empirically derived equation, a low risk group of 109 patients was identified with a calculated risk of seminal vesicle involvement of < or = 13% and an observed incidence of 7.3%. Among the high risk group of 79 patients, which included all patients with a calculated risk > 13%, 37% had seminal vesicle involvement (p < 0.001 low vs. high risk). Twenty percent of the rectal volume received on average above 86% of the total dose for the five plans which included the seminal vesicles compared to 68% for the five plans excluding the seminal vesicles. The doses to 40% of the rectal volume were 64% and 37% if the seminal vesicles were included and excluded, respectively. The dose to the bladder and femoral heads was also decreased but to a lesser extent.
The empirical formula predicts risk of seminal vesicle involvement with a higher degree of significance for a larger number of patients than either Gleason score, clinical stage, or prostate specific antigen alone. Based on an analysis of our first 100 patients treated with definitive conformal therapy alone, approximately 47% of those patients could have been treated excluding the seminal vesicles. Excluding the seminal vesicles may allow us to go to a higher total dose with less rectal toxicity.
评估治疗前前列腺特异性抗原、Gleason评分和临床分期作为临床局限性前列腺癌患者精囊受累风险预测指标的应用，并确定排除精囊对周围正常组织所接受剂量的影响。
将一个结合术前前列腺特异性抗原和Gleason评分的经验性推导公式应用于188例行根治性前列腺切除术且有精囊病理评估结果的患者。使用该公式定义精囊受累的高风险组和低风险组。将观察到的精囊受累风险与单独使用术前前列腺特异性抗原、Gleason评分或临床分期或使用经验公式预测的风险进行比较。比较了5例接受六野适形放疗患者的剂量体积直方图，包括包含和不包含精囊的情况。
使用经验性推导公式，确定了109例低风险组患者，计算出的精囊受累风险≤13%，观察到的发生率为7.3%。在79例高风险组患者中，包括所有计算风险>13%的患者，37%有精囊受累（低风险组与高风险组相比，p<0.001）。对于包含精囊的5个计划，直肠体积的20%平均接受了总剂量的86%以上，而对于不包含精囊的5个计划，这一比例为68%。如果包含和排除精囊，直肠体积40%所接受的剂量分别为64%和37%。膀胱和股骨头所接受的剂量也有所降低，但程度较小。
与单独的Gleason评分、临床分期或前列腺特异性抗原相比，该经验公式对更多患者预测精囊受累风险具有更高的显著性。基于对我们最初100例仅接受确定性适形治疗患者的分析，大约47%的患者可以在不包括精囊的情况下进行治疗。排除精囊可能使我们能够提高总剂量，同时降低直肠毒性。
