Prostate cancer pathologic stage pT2b (2002 TNM staging system): does it exist?

The TNM 8th edition: Validation of the proposal for organ - confined (pT2) prostate cancer

Purpose:

The 8^th edition of the TNM has been updated and improved in order to ensure a high degree of clinical relevance. A major change in prostate includes pathologically organ - confined disease to be considered pT2 and no longer subclassified by extent of involvement or laterality. The aim of this study was to validate this major change.

Materials and Methods:

Prostates were step - sectioned from 196 patients submitted to radical prostatectomy with organ confined disease (pT2) and negative surgical margins. Tumor extent was evaluated by a semiquantitative point count method. The dominant nodule extent was recorded as the maximal number of positive points of the largest single focus of cancer from the quadrants. Laterality was considered as either total tumor extent (Group 1) or index tumor extent (Group 2). Time to biochemical recurrence was analyzed with the Kaplan - Meier product limit analysis and prediction of shorter time to biochemical recurrence with Cox proportional hazards model.

Results:

In Group 1, 43 / 196 (21.9%) tumors were unilateral and 153 / 196 (78.1%) bilateral and in Group 2, 156 / 196 (79.6%) tumors were unilateral and 40 / 196 (20.4%) bilateral. In both groups, comparing unilateral vs bilateral tumors, there was no significant clinicopathological difference, and no significant association with time as well as prediction of shorter time to biochemical recurrence following surgery.

Conclusions:

Pathologic sub - staging of organ confined disease does not convey prognostic information either considering laterality as total tumor extent or index tumor extent. Furthermore, no correlation exists between digital rectal examination and pathologic stage.

A modified point count method as a practical approach to assess the tumor volume and the percent gland involvement by prostate carcinoma

This study reports a modified point-count method for quantifying the extent of carcinoma in prostatectomy specimens (n=143), as adapted from Billis et al. (2003) [3]. The prostates were studied as follows: the basal/apical margins were sampled using the cone method. The remainder of the gland was divided into 12 quadrant-shaped regions that were sampled using two slices. Eight equidistant points were marked directly on the coverslip over each fragment. The points inside the tumoral areas were counted and expressed as both the percentage of prostate gland involvement by carcinoma (PGI) and the tumor volume (TV). A significant correlation between the preoperative PSA levels and each of the three quantitative estimations were observed, with improved correlations with the PGI and TV values obtained using the point-count method (viz. number of slices involved (NSI) (r=0.32), PGI (r=0.39) and TV (r=0.44)). With the data sets stratified into three categories, all three methods correlated with multiple parameters, including Gleason scores ≥7, primary Gleason scores ≥4, perineural/angiolymphatic invasion, extraprostatic extension, seminal vesicle invasion and positive margins. All three quantitative methods were associated with morphologic features of tumor progression. The results obtained using this modified point-count method correlate more strongly with preoperative PSA levels.

Histological characteristics of the index lesion in whole-mount radical prostatectomy specimens: implications for focal therapy

It has been suggested that in multifocal prostate cancer (PCa), focal therapy to the largest (index) lesion is sufficient, because secondary non-index lesions are unlikely to contribute to disease progression. In this study, the role of PCa focality in selecting men for focal therapy was evaluated. A histopathological analysis of the index and non-index lesions of 100 consecutive radical prostatectomy specimens was carried out. Cases that would have been suitable for focal ablation were also evaluated. Tumours were more often multifocal (78%) and bilateral (86%). In total, 270 tumour foci were identified. In multifocal disease, tumour volume, Gleason score and pathological stage were almost invariably defined by the index lesion of the specimen; among the 170 satellite foci, 148 (87%) were <0.5 cm(3) and 169 (99.4%) had Gleason score ≤ 6. Using the defined criteria, 51% of men in this series would have been considered suitable for focal ablation of the index lesion. Histological features of poor prognosis in the prostate are associated with the index lesion. There is a high proportion of patients who may be suitable for focal therapy, and clinical trials of index lesion ablation should be considered as part of this therapeutic strategy.

Should pathologists continue to use the current pT2 substaging system for reporting of radical prostatectomy specimens?

OBJECTIVES

Pathologic staging tries to maintain symmetry with clinical staging, allowing a direct comparison of both. However, in contrast to clinical substaging of T2 prostate cancers, is controversial whether pathologic T2 substaging conveys prognostic information. The aim of our study is to analyze the clinicopathologic findings and the prognostic information comparing the clinical with the pathological T2 substaging of patients submitted to radical prostatectomy.

MATERIALS AND METHODS

Using the 2009 TNM staging system, 169 patients with clinical stage T2a were compared with patients with stage T2b/T2c, and 142 patients with pathological stage T2a were compared with patients with stage T2c. All surgical specimens were step-sectioned. Using a semiquantitative point-count method for tumor extent evaluation, all insignificant tumors were excluded from analysis. Clinicopathological characteristics were compared between the groups. Biochemical recurrence data were compared using log-rank analysis, and significant predictors of time to biochemical recurrence were determined using univariate and multivariate Cox proportional hazards model.

RESULTS

There was significant difference in biochemical recurrence rates between men with clinical T2a versus T2b/T2c tumors but no difference between men with pathological T2a versus T2c tumors. No patient in pathologic stage T2b was found. On multivariate analysis, clinical stage T2b/T2c was independent predictor of time to biochemical recurrence following surgery but not pathological stage T2c.

CONCLUSIONS

There is lack of symmetry between clinical and pathological T2 substaging as predictors of time to biochemical recurrence following surgery. The findings support a reevaluation of the TNM pathologic T2 stage, which should not be substratified.

International Society of Urological Pathology (ISUP) Consensus Conference on Handling and Staging of Radical Prostatectomy Specimens. Working group 2: T2 substaging and prostate cancer volume

The 2009 International Society of Urological Pathology consensus conference in Boston made recommendations regarding the standardization of pathology reporting of radical prostatectomy specimens. Issues relating to the substaging of pT2 prostate cancers according to the TNM 2002/2010 system, reporting of tumor size/volume and zonal location of prostate cancers were coordinated by working group 2. A survey circulated before the consensus conference demonstrated that 74% of the 157 participants considered pT2 substaging of prostate cancer to be of clinical and/or academic relevance. The survey also revealed a considerable variation in the frequency of reporting of pT2b substage prostate cancer, which was likely a consequence of the variable methodologies used to distinguish pT2a from pT2b tumors. Overview of the literature indicates that current pT2 substaging criteria lack clinical relevance and the majority (65.5%) of conference attendees wished to discontinue pT2 substaging. Therefore, the consensus was that reporting of pT2 substages should, at present, be optional. Several studies have shown that prostate cancer volume is significantly correlated with other clinicopathological features, including Gleason score and extraprostatic extension of tumor; however, most studies fail to demonstrate this to have prognostic significance on multivariate analysis. Consensus was reached with regard to the reporting of some quantitative measure of the volume of tumor in a prostatectomy specimen, without prescribing a specific methodology. Incorporation of the zonal and/or anterior location of the dominant/index tumor in the pathology report was accepted by most participants, but a formal definition of the identifying features of the dominant/index tumor remained undecided.

Evaluation of pT2 subdivisions in the TNM staging system for prostate cancer

OBJECTIVE

To evaluate the subclassifications of pT2 diseases in tumour-nodes-metastases (TNM) staging system for prostate cancer.

PATIENTS AND METHODS

We retrospectively analysed the data of 372 patients who underwent radical retropubic prostatectomy (RRP) for pathologically organ-confined prostate cancer at our institution. Pathological staging of all subjects were re-evaluated using the 1997 and the 2002 TNM staging system for prostate cancer. Various clinicopathological features along with biochemical recurrence-free survival (BRFS) of pT2 subgroups were assessed.

RESULTS

Using the 2002 TNM staging criteria, 87 of the tumours (23.4%) were pT2a, and 284 (76.3%) were pT2c. Of all subjects, there was only one (0.3%) pathological 2002 T2b tumour identified. When subjects were classified according to the 1997 versions of the T2 subclassification (pT2a vs pT2b), the 1997 pT2a and pT2b cases showed no significant difference regarding BRFS (log-rank P = 0.645) among those who were followed-up for >2 years after RRP. Also, pathological stage (1997 pT2a vs pT2b) was not a significant predictor of BRFS in either uni- or multivariate analysis (P = 0.289 and P = 0.241, respectively). Only preoperative serum PSA level and pathological Gleason score along with positive surgical margin were significant predictors of PSA outcome after RRP on multivariate analysis.

CONCLUSION

Our results suggest that two- or three-tiered subclassification of pT2 organ-confined prostate cancer via methods used in the previous or current TNM staging system may not be appropriate. Efforts should be made to upgrade the current TNM staging system for prostate cancer.

Prognostic value of morphologic and clinical parameters in pT2 - pT3 prostate cancer

OBJECTIVES

Verify the efficacy of clinical and morphologic parameters currently applied, including an immunohistochemical panel, in the prognostic of prostate cancer, in specific stages of the disease.

MATERIALS AND METHODS

In the period from 2002 to 2005, 40 surgical specimens were selected from patients submitted to radical prostatectomy, with their respective diagnostic biopsies. Based on the pathological stage pT2 or pT3, the specimens were separated into two groups, each one with 20 specimens. The results were confronted with pre- and postoperative clinical data. Between the groups studied, the following was also analyzed: the profile of the expression of molecular markers such as PSA, E-caderin, chromogranin-A, synaptofisin, P53 and Ki-67, both in the material coming from the prostatic biopsy and from the surgical specimens of all patients.

RESULTS

Data showed that patients with prostate-confined disease (pT2) presented lower PSA and Gleason score rates, in relation to the group with extra-prostatic disease (pT3). Quantitative measures obtained for the percentage of positive fragments from the biopsy revealed that patients from the pT2 group presented a lower mean percentage when compared to the pT3 group. Positive margins of both groups influenced the need for complementary treatment before biochemical progression. The comparison of the molecular marker expression in both stages was not significantly different.

CONCLUSION

It is evident the need to improve new methods, predominantly morphologic and molecular, that are able to further exploit the study of the material from the prostatic biopsy. As to the profile of the molecular markers used in both studied groups, there was no significant difference in the sense of outlining an additional prognostic factor in the clinical practice.