Prediction of prostate cancer in extended-field biopsies of the prostate

Preoperative clinical factors for diagnosis of incidental prostate cancer in the era of tissue-ablative surgery for benign prostatic hyperplasia: a korean multi-center review

PURPOSE

To identify potential predictive factors of incidental prostate cancer (IPca) in patients considering tissue-ablation treatment for benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

From the 11 centers, 1,613 men who underwent transurethral resection of the prostate (TURP) or open prostatectomy were included. Before surgery, prostate biopsy was performed in all patients with prostate-specific antigen (PSA) ≥4.0 ng/ml or with abnormal digital rectal examination (DRE) findings. The patients with prostate cancer preoperatively or with PSA >20 ng/ml were excluded. As predictive factors of IPca, age, body mass index, PSA, DRE, and transrectal ultrasonography (TRUS) findings, including total prostate volume (TPV), transition zone volume (TZV), and the presence of hypoechoic lesions, were reviewed. PSA density (PSAD) and PSAD in the transition zone (PSAD-TZV) were calculated.

RESULTS

IPca was diagnosed in 78 patients (4.8%). DRE findings, PSA, and TZV were independent predictive factors in the multivariate analysis. In the receiver operating characteristic curve analysis of PSA, PSAD, and PSAD-TZV, the area under the curve (AUC) was the largest for PSAD-TZV (AUC, 0.685).

CONCLUSIONS

IPca was detected in 4.8% of the population studied. In addition to DRE findings, the combination of TZV and PSA can be useful predictive factors of IPca in patients considering tissue-ablation treatment as well as TURP.

Prediction of prostate cancer recurrence using magnetic resonance imaging and molecular profiles

PURPOSE

To evaluate whether pretreatment magnetic resonance imaging (MRI)/MR spectroscopic imaging (MRSI) findings and molecular markers in surgical specimens correlate with each other and with pretreatment clinical variables (biopsy Gleason score, clinical stage, and prostate-specific antigen level) and whether they contribute incremental value in predicting prostate cancer recurrence.

EXPERIMENTAL DESIGN

Eighty-eight prostate cancer patients underwent MRI/MRSI before radical prostatectomy; imaging findings were scored on a scale of 1 to 7 (no tumor seen-lymph node metastasis). Ki-67, phospho-Akt, and androgen receptor expression in surgical specimens were assessed by immunohistochemistry. To examine correlations between markers and imaging scores, Spearman's correlation was used. To test whether markers and imaging scores differed by clinical stage or Gleason score, Wilcoxon's rank sum test was used. To examine time to recurrence, the methods of Kaplan-Meier were used. Cox proportional hazards models were built and their concordance indices (C-indices) were calculated to evaluate prediction of recurrence.

RESULTS

All markers correlated moderately strongly with MRI/MRSI score (all correlation coefficients >0.5). Markers and MRI/MRSI score were strongly associated with clinical stage and biopsy Gleason score (P < 0.01 for all). At last follow-up, 27 patients had recurrence. C-indices for MRI/MRSI score and all markers were associated with time to recurrence and ranged from 0.78 to 0.89. A Cox model combining all clinical predictors had a C-index of 0.89; the C-index increased to 0.95 when MRI/MRSI score was added and to 0.97 when markers were also added.

CONCLUSIONS

MRI/MRSI findings and molecular markers correlated well with each other and contributed incremental value to clinical variables in predicting prostate cancer recurrence.

Systematic lateral prostate biopsy--are the benefits worth the costs?

PURPOSE

We quantified the additional benefit of routinely adding 4 lateral biopsies to the initial sextant and transrectal ultrasound lesion targeted biopsy pattern in terms of cancer detection. We related this to costs.

MATERIALS AND METHODS

Prospective data were accrued on 1,010 consecutive patients referred for initial transrectal ultrasound directed prostate biopsy between June 16, 2000 and September 1, 2005. Costs were estimated for the pathology and clinical departments in terms of staff time.

RESULTS

Of 1,010 patients 494 (48.9%) were diagnosed with prostate adenocarcinoma. In these cases 411 cancers (83%) were found in medial samples, including 107 (22%) isolated to medial cores alone and 304 (62%) in medial and lateral cores. Only 55 patients (5.4%) had cancer isolated to systematic lateral cores. Of these cancers 30 (3%) were defined as clinically significant based on Gleason grade 7 or greater, or Gleason grade 6 involving more than 5% of any core. There was a 24% increase in biopsy related costs and a 36% increase in pathology costs associated with the 4 additional lateral biopsies.

CONCLUSIONS

Medial sextant and targeted biopsy directed at transrectal ultrasound identified lesions detects 94.6% of the prostate cancer that is detected with a 10 core biopsy protocol. The latter detects an extra 3% of clinically significant prostate cancer, while increasing costs by 30%. It is important to consider the absolute benefits of systematic lateral prostate biopsy in light of this additional expense when selecting an appropriate transrectal ultrasound biopsy regimen for a patient suspected of harboring prostate cancer.

Contemporary issues in the diagnosis of prostate cancer for the radiologist

Prostate cancer diagnostic techniques have improved considerably in recent years, but they must yet be optimised to ensure cancer detection at a potentially curable stage. Arrangements for prostate biopsy vary throughout Europe, and prostate biopsy may be undertaken by urologists or radiologists. This review discusses current issues relevant for radiologists involved in the detection of early prostate cancer. Prostate biopsy should be based on a systematic approach involving 8-12 cores obtained with peri-prostatic infiltration of local anaesthetic. Quality issues being considered by the United Kingdom Prostate Cancer Risk Management Programme are discussed.

Characteristics of patients with stage T1b incidental prostate cancer

OBJECTIVE

To study the characteristics of patients with incidental prostate cancer.

MATERIAL AND METHODS

The proportion of incidentally diagnosed prostate cancer was investigated in patients who underwent transurethral resection of the prostate (TURP) at our clinic over a 5-year period. "True" incidental prostate cancer was defined as cases where the preoperative digital rectal examination (DRE) and the prostate-specific antigen (PSA) value were normal. Patients with known malignancy of the prostate were excluded, together with those with PSA >4 ng/ml and/or a positive DRE. The characteristics of these patients were compared to those of benign prostatic hyperplasia patients and the group as a whole.

RESULTS

Of the 786 patients operated on between 1999 and 2003, 34 (4.3%) had a positive pathology report for "true" incidental prostate cancer. An increased frequency of poorly differentiated tumors (32.3%) was noted. Of the 34 patients, 17 were stage T1a and 17 T1b; 11 patients had a Gleason sum of 7-10, all of them in the T1b group. In the T1b group the mean age was 74 years, the mean PSA level 2.9 ng/ml and the mean weight of tissue resected 11.1 g. Corresponding values in the T1a patients were 70.1 years, 3.32 ng/ml and 18.2 g.

CONCLUSIONS

Compared to previous studies, we noticed a low incidence of "true" incidental prostatic carcinoma but a high ratio of poorly differentiated tumors (all stage T1b). Compared to the group as a whole, patients with incidental prostate cancer were older and had smaller prostate and transition zone volumes. Further research is needed to identify parameters that may aid in the earlier identification of incidental prostate cancer, as patients may benefit from curative treatment.

Impact of multiple biopsy cores on predicting final tumor volume in prostate cancer detected by a single microscopic focus of cancer on biopsy

OBJECTIVES

To compare the impact that the number of biopsy cores have on final pathologic findings when minimal disease is detected at biopsy. Discordance has been noted between transrectal ultrasound-guided biopsy results and tumor volume even when minimal amounts of tumor are found on biopsy.

METHODS

We identified patients who had undergone radical retropubic prostatectomy for a single microscopic focus of adenocarcinoma from a prospectively maintained surgical database. Patients were stratified into two groups: those with six biopsies or less and those with seven or more. The Gleason score, margin status, presence of extracapsular extension, and percentage of tumor volume were compared.

RESULTS

A total of 102 patients in our database had a single microscopic focus of adenocarcinoma detected by needle biopsy. Of these patients, 65 underwent six or fewer biopsies and 37 underwent seven or more at transrectal ultrasonography. Of the 37 patients in group 2, 27 (73%) had a final tumor volume of less than 5% compared with 24 (37%) of 65 patients in group 1 (P = 0.002). Of the group 2 patients, 15 (75%) with Stage T1c had an estimated tumor volume of less than 5% compared with only 11 (34%) in group 1 (P = 0.01). No statistically significant difference was noted between the two groups for margin status, presence of extracapsular extension, or Gleason score.

CONCLUSIONS

A single microscopic focus of cancer obtained after multiple cores predicts for a significantly lower tumor volume on final pathologic examination across clinical stages. In the context of greater tissue sampling, the minimal disease designation may carry more predictive value and be a useful parameter in stratifying patients with Stage T1c and other good-risk factors with regard to surgical outcome.