Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland 21231, USA.
J Urol. 2011 Sep;186(3):790-7. doi: 10.1016/j.juro.2011.02.2695. Epub 2011 Jul 23.
This review addresses the controversies that persist relating to the prognosis and reporting of tumor volume in adenocarcinoma of the prostate.
A search was performed using the MEDLINE database and referenced lists of relevant studies to obtain articles addressing the quantification of cancer on radical prostatectomy and needle biopsy.
In the 2010 TNM classification system T2 tumor at radical prostatectomy is subdivided into pT2a (unilateral tumor occupying less than ½ a lobe), pT2b (unilateral tumor greater than ½ a lobe) and pT2c (bilateral tumor). This pathological substaging of T2 disease fails on several accounts. In most studies pT2b disease almost does not exist. By the time a tumor is so large that it microscopically occupies more than ½ a lobe, in the majority of cases there is bilateral (pT2c) tumor. An even greater flaw of the substaging system for stage pT2 disease is the lack of prognostic significance. In reporting pathologically organ confined cancer, it should be merely noted as pT2 without further subclassification. The data are conflicting as to the independent prognostic significance of objective measurements of tumor volume in radical prostatectomy specimens. The most likely explanation for the discordant results lies in the strong correlation of tumor volume with other prognostic markers such as extraprostatic extension and positive margins. In studies where it is statistically significant on multivariate analysis, it is unlikely that knowing tumor volume improves prediction of prognosis beyond routinely reported parameters to the degree that it would be clinically useful for an individual patient. An alternative is to record tumor volume as minimal, moderate or extensive, which gives some indication to the urologist as to the extent of disease. Not only does providing an objective measurement not add useful prognostic information beyond what is otherwise routinely reported by the pathologist, but many objective measurements done in routine practice will likely not be an accurate indicator of the true tumor volume. There is also a lack of consensus regarding the best method of measuring tumor length when there are multiple foci in a single core separated by benign intervening prostatic stroma. Some pathologists, this author included, consider discontinuous foci of cancer as if it was 1 uninterrupted focus, the rationale being that these discontinuous foci are undoubtedly the same cancer going in and out of the plane of section. Measuring the cancer from where it starts to where it ends on the core gives the minimal length of cancer in the prostate. Others measure each focus individually, and the sum of these measurements is considered the cancer length on the core. Quantifying cancer with an ocular micrometer to record the total length or percent length of cancer is time-consuming, and the data are conflicting whether this is superior to other, simpler methods and whether any potential differences in predictive accuracy would translate into changes in clinical management. It is recommended that at a minimum the number of positive cores be recorded, unless fragmented involved cores preclude evaluation, along with at least 1 other more detailed measurement such as the percent of core involvement or length of cancer.
Consensus has been reached on some of the issues relating to quantifying tumor volume in prostate cancer, such as the lack of utility of substaging pT2 disease. Other questions such as whether to include or subtract intervening benign prostate tissue on prostate needle cores will require additional studies. Finally, matters such as the need to quantify cancer at radical prostatectomy or which method of quantifying cancer on needle biopsy is superior will likely remain contentious due to the close interrelationship and redundancy of prognostic variables.
本综述旨在探讨前列腺腺癌肿瘤体积预后和报告方面仍然存在的争议。
通过 MEDLINE 数据库和相关研究的参考文献列表进行检索，以获取有关根治性前列腺切除术和针吸活检中癌症定量的文章。
在 2010 年的 TNM 分期系统中，T2 肿瘤在根治性前列腺切除术中进一步分为 pT2a（单侧肿瘤占据不到半叶）、pT2b（单侧肿瘤大于半叶）和 pT2c（双侧肿瘤）。这种 T2 疾病的病理亚分期存在多个缺陷。在大多数研究中，pT2b 疾病几乎不存在。当肿瘤变得如此之大，以至于显微镜下占据超过半叶时，在大多数情况下，肿瘤已经是双侧的（pT2c）。分期为 pT2 的肿瘤亚分期系统的更大缺陷是缺乏预后意义。在报告病理上局限于器官的癌症时，只需注明为 pT2，无需进一步分类。肿瘤体积在根治性前列腺切除标本中的客观测量的独立预后意义存在争议。最可能的解释是肿瘤体积与其他预后标志物（如前列腺外延伸和阳性切缘）密切相关。在多变量分析中具有统计学意义的研究中，了解肿瘤体积对预后的预测作用不太可能超过常规报告的参数，以至于对个体患者具有临床意义。另一种方法是将肿瘤体积记录为最小、中度或广泛，这可以向泌尿科医生表明疾病的严重程度。提供客观测量值不仅不会在病理学家常规报告的基础上提供有用的预后信息，而且在常规实践中进行的许多客观测量值可能都不是肿瘤真实体积的准确指标。在单个核心中存在多个焦点且被良性前列腺间质分隔的情况下，如何测量肿瘤长度也存在共识。一些病理学家，包括作者本人，认为不连续的癌症焦点就像一个不间断的焦点一样，如果这些不连续的焦点无疑是同一癌症在切片平面内外进出。从核心上癌症开始到结束测量癌症，可以获得前列腺中癌症的最小长度。其他人则分别测量每个焦点，将这些测量值相加即为核心上的癌症长度。使用目镜测微器定量癌症以记录癌症的总长度或百分比长度既耗时又费力，而且关于这是否优于其他更简单的方法以及任何潜在的预测准确性差异是否会转化为临床管理的变化，数据存在争议。建议至少记录阳性核心的数量，除非碎片化的受累核心无法评估，同时至少要进行其他更详细的测量，例如核心受累的百分比或癌症的长度。
在与前列腺癌肿瘤体积定量相关的一些问题上已经达成共识，例如对 T2 疾病进行亚分期的实用性不足。其他问题，例如是否包括或减去前列腺针吸活检核心中的良性前列腺组织，还需要进一步的研究。最后，诸如是否需要在根治性前列腺切除术中定量癌症或哪种定量癌症的方法更优等问题，由于预后变量之间的密切相互关系和冗余性，可能仍然存在争议。
