Analysis of Risk Factors for Progression in Patients with Pathologically Confined Prostate Cancers After Radical Retropubic Prostatectomy:

Low Gleason score prostatic adenocarcinomas are no longer viable entities

Gleason scoring is the most powerful predictor of the behaviour of prostatic adenocarcinoma. It was devised more than 30 years ago and is used by pathologists worldwide. However, advances in immunochemistry and the understanding of the biological potential of some tumours have made the diagnosis of tumours of grades 1 and 2, and hence low score (2-4), a rarity. It is suggested that Gleason score 2(1 + 1) tumours, if they do exist, are so rare and so benign that they are a redundant entity and should not be identified as a malignancy. Similar problems revolve around the diagnosis of Gleason score 4(2 + 2) tumours and the criteria for their diagnosis are difficult to evaluate and revolve around reference to the score 2(1 + 1) lesion. The continued presence of low-grade tumours in the Gleason grading system leads to diagnostic confusion, potential error and, more importantly, confusion for patients diagnosed with score 6(3 + 3) tumours. I suggest that Gleason grade 1 (and therefore scores of 2 and 3) should be removed from the Gleason grading system. Gleason grade 2 (and therefore score 4 and 5) tumours require serious re-evaluation if they are to remain clinically useful diagnoses.

Telomerase activity in disseminated prostate cancer cells

OBJECTIVE

To analyse telomerase activity in disseminated prostate cancer cells isolated from bone marrow aspirates taken from men with localized prostate cancer before radical prostatectomy (RP).

PATIENTS AND METHODS

Disseminated epithelial prostate cancer cells were isolated from bone marrow aspirates from 69 men with localized prostate cancer before RP, by magnetic column-chromatography enrichment, followed by isolation of fluorescently labelled epithelial cells by micropipetting. We used pools of 10 non-epithelial bone marrow cells after tumour cell enrichment as control samples. These pure cell pools were tested for the presence of telomerase activity.

RESULTS

In all, 49 of the patient samples contained disseminated prostate cancer cells. Homogeneous pools of 10 cells were obtained from 35 of these; 49% of the 35 specimens showed telomerase activity, whereas all five control samples did not. Telomerase activity in the 35 samples was not significantly associated with Gleason score, preoperative prostate-specific antigen level, tumour stage, or surgical margin status. Follow-up is continuing to assess an association with disease recurrence.

CONCLUSION

This work shows the feasibility of isolating disseminated cancer cells for analysing individual or pooled cells. Compared to tissue staining, where telomerase is detected in 80-90% of samples, we found lower rates of telomerase activity in the disseminated tumour cells (49%). Telomerase-negative cells might provide information about cell dormancy, as telomerase is a marker of cell proliferation in immortal and cancer cells. Telomerase-positive cells might predict early disease recurrence, but a longer follow-up is needed to test this possibility.

Proliferating-cell nuclear antigen (PCNA) as an independent prognostic marker in patients after prostatectomy: a comparison of PCNA and Ki-67

OBJECTIVE

To investigate the prognostic value of prostatic tumour cell proliferation, as measured by Ki-67 and proliferating cell nuclear antigen (PCNA), and to compare these measures in men at low and high risk for progression of tumour.

PATIENTS AND METHODS

Two groups of patients with prostate cancer, i.e. 'metastatic' (M, 22) who had pT3b-4aN0M0 and pTanyN1M0, and 'nonmetastatic' (NM, 18), who had < or =pT3aN0M0 disease, were selected from a well-examined and mapped group of 114 treated by radical prostatectomy. Patients in the NM group were selected by the criteria of having a Gleason score of < or = 7. To assess proliferation, 1000 cells were counted at x 400 magnification by two observers and the percentage of tumour cells positively stained with Ki-67 and PCNA defined as the Ki-67 and PCNA labelling index (LI), respectively. The two LI were compared in the NM and M groups, and the correlation of the LIs with pathological stage, progression and prostate-specific antigen (PSA)-free survival evaluated. Prognostic values of the LI were analysed using multivariate analysis.

RESULTS

The mean (range) follow-up was 33 (4-78) months. The mean LIs were higher in the M than the NM group for both PCNA and Ki-67 (P = 0.02 and 0.019, respectively). Both LIs were markedly different between the groups when stratified by progression, with both significantly higher in men with progression in the NM group. Both LIs had a significant association with Gleason score, pathological stage, progression and PSA-free survival. In multivariate analysis the PCNA LI, surgical margin status and pathological stage were independent factors for progression.

CONCLUSION

Tumour cell proliferation as assessed by Ki-67 or PCNA correlate significantly with progression. The PCNA LI was an independent predictor of progression, especially in patients with a low risk of progression according to predefined criteria.