Chen M E, Troncoso P, Johnston D A, Tang K, Babaian R J
Department of Urology, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
J Urol. 1997 Dec;158(6):2168-75. doi: 10.1016/s0022-5347(01)68188-6.
We evaluated and optimized the detection of cancer by prostate biopsies. We developed a stochastic computer simulation model of ultrasound guided biopsies using mathematically reconstructed radical prostatectomy specimens. Use of this technique allows rapid evaluation of a variety of factors for their effect on prostate biopsy results. We used this model to analyze the effectiveness of sextant biopsies, which have been widely adopted in clinical practice. We also analyzed other biopsy schemes.
A total of 607 tumor foci from 180 serially sectioned whole mount radical prostatectomy specimens was mapped and digitized. The cancers had been clinically diagnosed by a variety of biopsy strategies. Simulated parasagittal sextant biopsies were performed for each case. Forty simulation runs (each consisting of a set of 6 biopsies) were performed for each prostate, with realistic random variations in sextant biopsy localization programmed in each run. Cancer detection by biopsy was considered reliable if 90% of the simulation runs for each prostate were positive for cancer. A summary algorithm was used to map the tumor foci.
Simulation of sextant biopsies demonstrated reliably detected cancer in only 107 of 147 patients (73%) in whom total tumor volume was greater than 0.5 cc. There was little correlation between total length of cancer in biopsy cores and tumor volume. Change of biopsy angle from 30 to 45 degrees did not result in significantly increased detection rates. Similarly, placing all biopsies more laterally did not increase overall detection rates. When we mapped tumor foci from the 40 cases in which sextant biopsies did not reliably detect tumor, we found that the foci were distributed in areas not biopsied by the sextant method, that is the transition zone, midline peripheral zone and inferior portion of the anterior horn of the peripheral zone. A 10-core biopsy scheme incorporating these areas as well as the posterolateral prostate reliably detected cancer in 141 of 147 patients (96%) with total tumor volumes greater than 0.5 cc.
Prostate cancer of significant volume can be present in areas not sampled by standard sextant biopsies. Biopsies of the transition zone, midline peripheral zone and inferior portion of the anterior horn of the peripheral zone should be considered for re-biopsy strategy after negative sextant biopsies. Sampling of these additional areas also can be incorporated in an initial biopsy scheme to increase overall initial rates of detection of prostate cancer.
我们评估并优化了前列腺活检对癌症的检测。我们利用数学重建的根治性前列腺切除术标本开发了一种超声引导活检的随机计算机模拟模型。使用该技术能够快速评估多种因素对前列腺活检结果的影响。我们用这个模型分析了临床实践中广泛采用的六分区活检的有效性。我们还分析了其他活检方案。
对180个连续切片的根治性前列腺切除术标本中的607个肿瘤病灶进行了定位和数字化处理。这些癌症已通过多种活检策略进行了临床诊断。对每个病例进行模拟矢状面六分区活检。对每个前列腺进行40次模拟操作（每次由一组6次活检组成），每次操作中六分区活检定位都编入了实际的随机变化。如果每个前列腺90%的模拟操作活检结果为癌症阳性，则认为活检检测癌症可靠。使用一种汇总算法对肿瘤病灶进行定位。
六分区活检模拟显示，在147例肿瘤总体积大于0.5立方厘米的患者中，只有107例（73%）可靠检测到癌症。活检芯中癌症的总长度与肿瘤体积之间几乎没有相关性。活检角度从30度变为45度并未导致检测率显著提高。同样，将所有活检位置更偏向外侧也未提高总体检测率。当我们对六分区活检未能可靠检测到肿瘤的40例病例中的肿瘤病灶进行定位时，我们发现病灶分布在六分区法未活检的区域，即移行区、中线外周区和外周区前角下部。一种包含这些区域以及前列腺后外侧的10芯活检方案在147例肿瘤总体积大于0.5立方厘米的患者中，有141例（96%）可靠检测到癌症。
大量前列腺癌可能存在于标准六分区活检未取样的区域。对于六分区活检结果为阴性的患者，重新活检策略应考虑对移行区、中线外周区和外周区前角下部进行活检。这些额外区域的取样也可纳入初始活检方案，以提高前列腺癌的总体初始检测率。
