Technical considerations when obtaining and interpreting prostatic biopsies from men with suspicion of early prostate cancer: Part I

Factors affecting the diagnosis of prostate cancer through 12 quadrant guided prostate biopsy

PURPOSE

Investigate the factors affecting the efficacy of the widely used 12-quadrant prostate biopsy for the diagnosis of prostate cancer.

METHODS

The data of 1846 male patients between 45 and 75 years of age was evaluated. The patients were subdivided into groups according to age, blood prostate-specific antigen (PSA) levels prostate volume (PV), digital rectal examination (DRE) findings, and pathology results. The tumour detection rates in the 12-quadrant biopsies were compared with PV, PSA levels, and DRE results of the grouped patients.

RESULTS

The tumour detection rate decreased with increasing PV in patients 45-75 years of age and with a PSA level ≤ 14.5. No decrease was detected in patients 45-60 years of age or those aged 61-75 years with a PSA ≤ 6.99 and suspicious DRE findings. A decrease in the tumour detection rate with increasing PV was observed in the other three subgroups of patients in this age group, who had a PSA ≤ 6.99, and normal DRE findings but a PV ≤ 40, PV 41-80, or PV ≥ 81.

CONCLUSIONS

Even though there is no statistically significant relationship between PV and the prostate cancer detection rate in patients 45-60 years of age, the cancer detection rate decreased with increasing PV in three of the four subgroups of patients between the ages of 61 and 75 years. Our study results have demonstrated that an individualised approach can play an important role in the diagnosis and treatment of prostate cancer.

Clinical Utility of Gallium-68 PSMA PET/CT Scan for Prostate Cancer

BACKGROUND

Prostate cancer is biologically and clinically a heterogeneous disease that makes imaging evaluation challenging. One of the important challenges in this cancer is to detect recurrent disease. Biochemical response using Prostate Specific Antigen (PSA) and Imaging using several PET tracers have poor sensitivity and specificity. Therefore, we analyse the role of Ga68-PSMA (Prostate Specific Membrane Antigen) imaging in prostate cancer, which is a new PET tracer.

METHODS

In this study, we evaluated PET scans of 262 patients with diagnosis of prostate cancer. These patients were scanned using Ga68-PSMA for either staging or response evaluation.

RESULTS

336 PSMA scans were performed. Ga68-PSMA scan resulted in the detection of extra-prostatic disease in 53.2% of cases when done at baseline before commencing any treatment. The sensitivity of Ga68-PSMA at baseline with histopathological diagnosis was 95% with 95% CI ranging from 86% to 98%. The positive predictive value was high at 98% with 95% CI ranging from 91% to 99%. In 26 (10%) patients who had surgical castration, Ga68-PSMA scan was able to detect disease progression / castration resistance in 100% of cases. The outcome of castration-resistant prostate cancer was compared with other cases where castration was not done. In those who did not undergo castration, there was a significantly better response by hormone therapy (p = 0.03) and radiotherapy (p = 0.01) on Ga68-PSMA. The sensitivity of Ga68-PSMA response with biochemical response was 66.7% with 95% CI ranging between 46 %- 82.7%. Ga68-PSMA response did not correlate with biochemical response.

CONCLUSION

Ga68-PSMA has good sensitivity for diagnosis, staging, restaging, evaluation of therapy response and prognostication in prostate cancer.

Comparison of transrectal ultrasound-guided biopsy of the prostate and transurethral resection of the prostate for detection of prostate cancer in patients with moderate lower urinary tract symptoms

BACKGROUND

To compare transrectal ultrasound (TRUS)-guided biopsy of the prostate and transurethral resection of the prostate (TURP) for detection of prostate cancer (PCa) in patients with moderate lower urinary tract symptoms (LUTS) by retrospective chart review.

METHODS

Between January 2004 and December 2008, a total of 520 patients, aged 50.3-81.5 years, with moderate LUTS (International Prostate Symptom Score, 8-19), and elevation of prostate-specific antigen (≥ 4 ng/mL), or abnormal findings by digital rectal examination, were enrolled for evaluation. All the patients were recommended to receive TRUS-guided biopsy of the prostate (TRUS biopsy group) or TURP (TURP group) due to the possibility of PCa, according to their choice after full explanation by the doctors.

RESULTS

There were 379 patients in the TRUS biopsy group and 141 in the TURP group. PCa was detected in 80 patients (21.1%) in the TRUS group and in 27 (19.1%) in the TURP group. Clinically localized PCa (T1-2N0M0) was found in 46 patients (57.5%) in the TRUS biopsy group and in 16 (59.3%) in the TURP group. Bone metastasis was noticed in 22 (27.5%) patients in the TRUS biopsy group and in 7 (25.9%) in the TURP group. The percentage of low-grade tumor was significantly higher in the TURP group than in the TRUS biopsy group (11.1% vs. 5%).

CONCLUSION

TURP was not superior to TRUS-guided biopsy of the prostate for detection of PCa in patients with moderate LUTS and prostate-specific antigen ≥ 4 ng/mL.

Does experimental pain assessment before biopsy predict for pain during transrectal ultrasound-guided prostate biopsy?

OBJECTIVES

To evaluate whether assessment of experimental pain perception using the modified tourniquet test before a biopsy procedure could predict the pain scores during transrectal ultrasound-guided prostate biopsy. However, the relationship between the experimental pain assessment before prostate biopsy and the pain scores during the biopsy procedure has not been established.

METHODS

A total of 67 men who underwent transrectal ultrasound-guided 12-core prostate biopsy were prospectively enrolled in the study. The day before biopsy, a modified submaximal effort tourniquet test was performed on all patients. During the test, pain scores were recorded at 30, 60, 90, and 120 seconds after inflation of the blood pressure cuff. Pain scores were also recorded during probe introduction into the rectum and prostate biopsy. Pain was assessed using a visual analogue scale (VAS).

RESULTS

A significant correlation was found between the VAS scores in the tourniquet test and the VAS scores during probe introduction and the VAS scores during prostate biopsy (P <0.0001). The most significant correlation was found between the VAS scores during prostate biopsy and the VAS 60-second scores during the tourniquet test (P <0.0001, r=0.756). No significant relation was found between the VAS scores and age, prostate volume, or prostate-specific antigen level (P >0.05).

CONCLUSIONS

Our results have shown that a simple and quick tourniquet test could be useful in identifying those men who will experience greater pain during transrectal ultrasound-guided prostate biopsy. In the light of these data, additional studies will be planned to evaluate whether experimental pain assessment before the procedure could predict the analgesic potency of pain-relieving treatment during prostate biopsy.

Serum prostate-specific antigen levels in Middle Eastern men with subclinical prostatitis

OBJECTIVE

To investigate the influence of subclinical or histologically diagnosed prostatitis on serum prostate-specific antigen (PSA) in patients investigated for prostatic disease in Kuwait.

MATERIALS AND METHODS

Serum PSA was assayed in patients investigated for prostatic disease in Mubarak Al-Kabeer Hospital, Kuwait, between December 2002 and December 2004. These included patients undergoing transrectal ultrasound with needle biopsy of the prostate gland and those who were treated with transurethral resection of the prostate or retropubic prostatectomy. The tissue was evaluated for prostatitis as well as the underlying disease, and the type and severity of prostatitis were compared with levels of serum PSA.

RESULTS

Of the 331 tissue specimens, 18 (5.4%) did not show prostatitis, while 233 (70.4%) with benign prostate and 80 (24.2%) with malignant prostate disease showed prostatitis. Of 270 men with known serum PSA levels, 198 and 72 had benign and malignant prostate disease, respectively. Of the 198, 77 (41%) with benign prostate disease and prostatitis and of the 72, 52 (76%) with malignant prostate disease and prostatitis had serum PSA levels >10 ng/ml.

CONCLUSION

The data showed that although raised serum PSA is more commonly associated with prostate cancer, subclinical prostatitis is a significant source of high serum PSA in over 40% of men in Kuwait. That local factors may obscure the usefulness of serum PSA as a screening tool suggests the need for a locally applicable paradigm to identify prostate cancer.