Predicting unilateral prostate cancer based on biopsy features: implications for focal ablative therapy--results from the SEARCH database

Can contralateral lymph-node metastases be ruled out in prostate cancer patients with only unilaterally positive prostate biopsy?

PURPOSE

Our study evaluated the diagnostic benefits of bilateral pelvic lymphadenectomy in prostate cancer patients with unilaterally positive prostate biopsy.

METHODS

Our retrospective analysis included clinical, surgical, and histopathological data of 440 prostate cancer patients treated with radical prostatectomy and bilateral sentinel-guided and risk-adapted complementary extended pelvic lymphadenectomy at our hospital between 2015 and 2022. We performed multiparametric logistic regression analysis to identify the most relevant predictive factors for detecting lymph-node metastasis in this group of patients.

RESULTS

Overall, 373 patients (85%) had histopathologically bilateral tumours and 45 (10%) pN1 status, of which 22 (49%) also had lymph-node metastasis contralateral to the side of the positive prostate biopsy. In two patients with confirmed unilateral disease in prostatectomy specimens, bilateral lymph-node metastases were observed. Eight pN1 patients would have been missed by unilateral pelvic lymphadenectomy, resulting in a false-negative rate of 18%, 82% sensitivity, and 98% accuracy. Clinical tumour category, International Society of Urological Pathology grade, and percentage of prostate biopsy cores that are positive, as well as number of dissected lymph nodes contralateral to positive prostate biopsy, were determined as the most relevant predictive factors for detecting lymph-node metastasis. Our analysis was limited by its retrospective nature as well as by the fact that 80% of the patients did not receive MRI-targeted biopsy.

CONCLUSION

Our study highlights the diagnostic value of bilateral pelvic lymphadenectomy and the need for careful planning in surgery for prostate cancer patients with unilaterally positive prostate biopsy.

Radiotherapy planning in a prostate cancer phantom model with intraprostatic dominant lesions using stereotactic body radiotherapy with volumetric modulated arcs and a simultaneous integrated boost

Aim

In the treatment of prostate cancer with radiation therapy, the addition of a simultaneous integrated boost (SIB) to the dominant intraprostatic lesions (DIL) may improve local control. In this study, we aimed to determine the optimal radiation strategy in a phantom model of prostate cancer using volumetric modulated arc therapy for stereotactic body radiotherapy (SBRT-VMAT) with a SIB of 1-4 DILs.

Methods

We designed and printed a three-dimensional anthropomorphic phantom pelvis to simulate individual patient structures, including the prostate gland. A total of 36.25 Gy (SBRT) was delivered to the whole prostate. The DILs were irradiated with four different doses (40, 45, 47.5, and 50 Gy) to assess the influence of different SIB doses on dose distribution. The doses were calculated, verified, and measured using both transit and non-transit dosimetry for patient-specific quality assurance using a phantom model.

Results

The dose coverage met protocol requirements for all targets. However, the dose was close to violating risk constraints to the rectum when four DILs were treated simultaneously or when the DILs were located in the posterior segments of the prostate. All verification plans passed the assumed tolerance criteria.

Conclusions

Moderate dose escalation up to 45 Gy seems appropriate in cases with DILs located in posterior prostate segments or if there are three or more DILs located in other segments.

Do contemporary imaging and biopsy techniques reliably identify unilateral prostate cancer? Implications for hemiablation patient selection

BACKGROUND

Hemiablation is a less morbid treatment alternative for appropriately selected patients with unilateral prostate cancer (PCa). However, to the authors' knowledge, traditional diagnostic techniques inadequately identify appropriate candidates. In the current study, the authors quantified the accuracy for identifying hemiablation candidates using contemporary diagnostic techniques, including multiparametric magnetic resonance imaging (mpMRI) and MRI-fusion with complete systematic template biopsy.

METHODS

A retrospective analysis of patients undergoing MRI and MRI-fusion prostate biopsy, including full systematic template biopsy, prior to radical prostatectomy in a single tertiary academic institution between June 2010 and February 2018 was performed. Hemiablation candidates had unilateral intermediate-risk PCa (Gleason score [GS] of 3+4 or 4+3, clinical T classification ≤T2, and prostate-specific antigen level <20 ng/dL) on MRI-fusion biopsy and 2) no contralateral highly or very highly suspicious Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) MRI lesions. Hemiablation candidates were inappropriately selected if pathologists identified contralateral GS ≥3+4 or high-risk ipsilateral PCa on prostatectomy. The authors tested a range of hemiablation inclusion criteria and performed multivariable analysis of preoperative predictors of undetected contralateral disease.

RESULTS

Of 665 patients, 92 met primary hemiablation criteria. Of these 92 patients, 44 (48%) were incorrectly identified due to ipsilateral GS ≥3+4 tumors crossing the midline (21 patients), undetected distinct contralateral GS ≥3+4 tumors (20 patients), and/or ipsilateral high-risk PCa (3 patients) on prostatectomy. The rate of undetected contralateral disease ranged from 41% to 48% depending on inclusion criteria. On multivariable analysis, men with anterior index tumors were found to be 2.4 times more likely to harbor undetected contralateral GS ≥3+4 PCa compared with men with posterior lesions (P < .05).

CONCLUSIONS

Clinicians and patients must weigh the risk of inadequate oncologic treatment against the functional benefits of hemiablation. Further investigation into methods for improving patient selection for hemiablation is necessary.

Identifying the dominant prostate cancer focal lesion using image analysis and planning of a simultaneous integrated stereotactic boost

BACKGROUND

Prostate cancer is now the only solid organ cancer in which therapy is commonly applied to the whole gland. One of the main challenges in adopting focal boost or true focal therapy is in the accurate mapping of cancer foci defined on magnetic resonance (MR) images onto the computerised tomography (CT) images used for radiotherapy planning.

MATERIAL AND METHODS

Prostate cancer patients (n = 14) previously treated at the Edinburgh Cancer Centre (ECC) were selected for this study. All patients underwent MR scanning for the purpose of diagnosis and staging. Patients received three months of androgen deprivation hormone therapy followed by a radiotherapy planning CT scan. The dominant focal prostate lesions were identified on MR scans by a radiologist and a novel image analysis approach was used to map the location of the dominant focal lesion from MR to CT. An offline planning study was undertaken on suitable patients (n = 7) to investigate boosting of the radiation dose to the tumour using a stereotactic ablative body radiotherapy (SABR) technique.

RESULTS

The non-rigid registration algorithm showed clinically acceptable estimates of the location of the dominant focal disease on all CT image data of patients suitable for a boost treatment. Standard rigid registration was found to produce unacceptable estimates of the dominant focal lesion on CT. A SABR boost dose of 47.5 Gy was delivered to the dominant focal lesion of all patients whilst meeting all dose-volume histogram (DVH) constraints. Normal tissue complication probability (NTCP) for the rectum decreased from 1.28% to 0.73% with this method.

CONCLUSIONS

These preliminary results demonstrate the potential of this image analysis method for reliably mapping dominant focal disease within the prostate from MR images onto planning CT images. Significant dose escalation using a simultaneous integrated SABR boost was achieved in all patients.

Twelve Core Template Prostate Biopsy is an Unreliable Tool to Select Patients Eligible for Focal Therapy

Introduction: To determine whether unilateral prostate cancer diagnosed at 12-core prostate biopsy harbours relevant prostate cancer foci in contralateral lobe in cases eligible for hemiablative focal therapy. Material and Methods: We analysed 112 radical prostatectomies of unilateral Gleason 6/7 prostate cancer based on prostate biopsy information. The presence of significant prostate cancer foci and/or the index lesion in the contralateral lobe is described. A subanalysis is performed in cases of Gleason score 6 and in cases of very-low-risk prostate cancer. Results: Contralateral prostate cancer was present in 69.6% of cases, fulfilling significant prostate cancer criteria in 33% and being the index lesion in 32%. No significant differences were found when analysing the Gleason 6 group (73% contralateral prostate cancer, 34% significant prostate cancer and 35% index lesion) or the very-low-risk prostate cancer group (80% contralateral prostate cancer, 29% significant prostate cancer and 45% index lesion). Conclusions: The assumption of unilateral prostate cancer based on 12-core template prostate biopsy information is unreliable. In about one third of the cases, there will be focus of significant prostate cancer or the index lesion in the contralateral lobe. This information should be taken into account when hemiablative focal therapies are considered.

A solitary positive prostate cancer biopsy does not predict a unilateral lesion in radical prostatectomy specimens

OBJECTIVE

Prostate cancer (PCa) may be a multifocal and bilateral disease. Patients with low-risk PCa and a low number of positive biopsy cores may choose to undergo active surveillance or focal therapy. The aim of this study was to determine the correlation between a solitary positive prostate biopsy core and the pathological outcome after radical prostatectomy (RP).

MATERIAL AND METHODS

The Michinoku Japan Urological Cancer Study Group database contains data, including preoperative and postoperative information, on 1268 consecutive patients with PCa treated with RP alone at four institutions. This study focused on 151 patients with a single positive biopsy core, preoperative prostate-specific antigen (PSA) level less than 10 ng/ml, biopsy Gleason score less than 8, and clinical stage T1c/T2a/T2b disease. Potential preoperative predictors of unilateral PCa were age, preoperative PSA level, biopsy Gleason score and clinical T stage.

RESULTS

The median age and preoperative PSA level were 65 years (range 47-76 years) and 6.00 ng/ml (range 0.50-9.80 ng/ml), respectively. Unilateral PCa was identified in 41% of the patients. Extraprostatic extension or seminal vesicle invasion was observed in 26% of all patients.

CONCLUSION

Serum PSA levels were significantly higher in the bilateral PCa group than in the unilateral PCa group in the current study. For patients with PCa having a solitary positive prostate biopsy core, definitive therapy such as RP should be considered.

Parameters predicting postoperative unilateral disease in patients with unilateral prostate cancer in diagnostic biopsy: a rationale for selecting hemiablative focal therapy candidates

BACKGROUND

Focal hemiablative therapy for prostate cancer is a new treatment alternative. Unilateral and unifocal disease are its main limitations. The aim of this study was to identify the epidemiological, clinical and pathological parameters that may predict unilateral disease in patients diagnosed with prostate cancer.

METHODS

We performed a retrospective analysis of patients at our institution between January 2005 and January 2011. Only patients with unilateral disease in prostate biopsy were part of the study. The analysis included age, preoperative prostate-specific antigen (PSA) and its density, prostate volume, biopsy first and second Gleason pattern and Gleason summary, number of biopsy cores, percentage of cancer in biopsy material and the presence of high-grade prostatic intraepithelial neoplasia. Their role as potential predictors was evaluated by univariate and multivariate analysis.

RESULTS

A total of 161 patients had unilateral disease after prostate biopsy. A significant correlation was found between prostate volume, PSA density and percentage of cancer in biopsy material and the presence of unilateral disease in the surgical specimen. These are the same factors significant in the univariate analysis. The results of the multivariate analysis demonstrated that PSA density (p = 0.015) and percentage of cancer in biopsy material (p = 0.028) are the most significant predictors.

INTERPRETATION

Our results demonstrate that PSA density and the percentage of cancer in biopsy cores are significant predictors for prostate cancer unilaterality and should be considered for the selection of hemiablative focal therapy candidates.

Discrepancy in prostate cancer localization between biopsy and prostatectomy specimens in patients with unilateral positive biopsy: implications for focal therapy

BACKGROUND

Unilateral ablative strategy success depends on reliable prediction of prostate cancer (PCA) location. We evaluated the discrepancy in PCA localization between unilateral positive biopsy (PBx) and radical prostatectomy (RP).

METHODS

Between 2004 and 2008, 431 patients were diagnosed with unilateral PCA by 12-core PBx; 179 underwent RP and constituted our study cohort. Specimens were reviewed to map tumor outline and determine number of cancer foci, tumor volume, Gleason score (GS), zone of origin, localization, and pathologic stage.

RESULTS

In 50 men, biopsy and prostatectomy findings correlated (unilateral tumor); in 129, PCA was detected in the contralateral side of the prostate. In 52 patients, 54 clinically significant tumors were missed by biopsy. When patients with true unilateral and missed contralateral disease at RP were compared with respect to prognostic parameters no significant differences were detected. Sixty-one of the 88 patients with preoperative low-risk disease had true unilateral (n = 21) or missed insignificant contralateral (n = 40) PCA; 27 had missed significant contralateral PCA at RP. PSA > 4 ng/ml predicted presence of significant bilateral disease in low-risk population (P = 0.004). Twenty-four of 27 patients with significant bilateral cancer had PSA > 4, although 33/61 with unilateral or bilateral insignificant cancer had similar elevated PSA values.

CONCLUSIONS

Twelve-core biopsy is inadequate to identify candidates for organ-sparing therapy. Most men with unilateral positive biopsies have bilateral cancer at prostatectomy. Tumors missed by biopsy were clinically significant in 40% of patients, but no prognostic parameters could predict unilateral disease. Hemi-ablative treatment might fail to eradicate significant lesions in the contralateral side.

There is no way to identify patients who will harbor small volume, unilateral prostate cancer at final pathology. implications for focal therapies

BACKGROUND

The aim of this study was to assess the clinical characteristics of the potentially ideal candidates for focal therapy, that is, patients with unilateral, small volume (namely, pT2a) prostate cancer (PCa) at radical prostatectomy (RP).

MATERIALS AND METHODS

We evaluated 2,503 consecutive pT2 PCa patients treated with RP between 2002 and 2009 at a single center. Within this population, the clinical characteristics of patients with pT2a and pT2b/c disease were compared. Univariable and multivariable logistic regression models were fitted to assess clinical predictors of pT2a at RP.

RESULTS

Overall, 349 patients (14%) had pT2a PCa, while the remaining patients had either pT2b (n = 334; 15.5%) or pT2c disease (n = 1,820 patients; 84.5%). Patients with pT2a PCa had a significantly lower mean PSA value, lower mean percentage of positive biopsy cores and lower biopsy Gleason score distribution (all P ≤ 0.03). However, at multivariable analyses, only percentage of positive cores maintained an independent predictor status (P = 0.01). Even when considering only patients sharing all the most favorable PCa characteristics (namely, clinical stage T1, PSA ≤ 4, Gleason score ≤6 and percentage of positive cores ≤25%), the rate of pT2a disease was only 24%.

CONCLUSIONS

The rate of small volume, unilateral PCa even among patients with extremely favourable PCa characteristics was remarkably low (roughly 25%). This suggests that: (1) Three quarters of the best candidates for focal therapy would ultimately show adverse pathological features; (2) At present, accurate identification of the ideal candidate for focal therapy is not possible with current clinical-pathologic parameters.

Management of Localized Prostate Cancer by Focal Transurethral Resection of Prostate Cancer: An Application of Radical TUR-PCa to Focal Therapy

Background. We analyzed radical TUR-PCa against localized prostate cancer. Patients and Methods. Seventy-nine out of 209 patients with prostate cancer in one lobe were studied. Patients' age ranged from 58 to 91 years and preoperative PSA, 0.70 to 17.30 ng/mL. In other 16 additional patients we performed focal TUR-PCa. Patients' age ranged from 51 to 87 years and preoperative PSA, 1.51 to 25.74 ng/mL. Results. PSA failure in radical TUR-PCa was 5.1% during the mean follow-up period of 58.9 months. The actuarial biochemical non-recurrence rate was 98.2% for pT2a and 90.5% for pT2b. Bladder neck contracture occurred in 28 patients (35.4%). In 209 patients, pathological study revealed prostate cancer of the peripheral zone near the neurovascular bundle bilaterally in 25%, unilaterally in 39% and no cancer bilaterally in 35%, suggesting the possibility of focal TUR-PCa. Postoperative PSA of 16 patients treated by focal TUR-PCa was stable between 0.007 and 0.406 ng/mL at 24.2 months' follow-up. No patients suffered from urinary incontinence. Bladder neck contracture developed in only 1 patient and all 5 patients underwent nerve-preserving TUR-PCa did not show erectile dysfunction. Conclusion. Focal TUR-PCa was considered to be a promising option among focal therapies against localized prostate cancer.

Focal therapy for prostate cancer: patient selection and evaluation

Recent stage migration toward low-risk prostate cancer, overtreatment of biologically insignificant tumors with radical prostatectomy at the additional expense of a non-negligible morbidity and undertreatment of patients improperly selected for active surveillance are the main reasons that have fueled the concept of focal therapy. Optimal selection of patients is the key for the successful implementation of focal therapy. Selection criteria for focal therapy vary widely and depend on clinical, histological and imaging characteristics of the patients that are highlighted in this article. In addition, the rationales, merits and limitations of the available methods for the assessment of potential candidates, the evaluation of treatment efficacy and follow-up of these patients are discussed.

Focal therapy for prostate cancer - where are we in 2011?

Prostate cancer treatment is a controversial topic amongst physicians and patients alike. Radical therapies such as prostatectomy and whole gland radiation offer the best outcomes in terms of oncologic efficacy, but the decision to undergo treatment must be weighed against its potential morbidity. Over the past decade, the concept of focal therapy for prostate cancer has been introduced as a potential method of achieving oncologic control with a lesser degree of morbidity. Focal therapy refers to isolated ablation of a tumor focus with sparing of uninvolved, surrounding tissue. While it remains in the early stages of development, considerable research is underway that will help determine the optimal method of achieving this goal. Current areas of investigation include appropriate candidate selection, lesion identification, modality of treatment, and follow-up strategies.

Suitability of PSA-detected localised prostate cancers for focal therapy: experience from the ProtecT study

Background:

Contemporary screening for prostate cancer frequently identifies small volume, low-grade lesions. Some clinicians have advocated focal prostatic ablation as an alternative to more aggressive interventions to manage these lesions. To identify which patients might benefit from focal ablative techniques, we analysed the surgical specimens of a large sample of population-detected men undergoing radical prostatectomy as part of a randomised clinical trial.

Methods:

Surgical specimens from 525 men who underwent prostatectomy within the ProtecT study were analysed to determine tumour volume, location and grade. These findings were compared with information available in the biopsy specimen to examine whether focal therapy could be provided appropriately.

Results:

Solitary cancers were found in prostatectomy specimens from 19% (100 out of 525) of men. In addition, 73 out of 425 (17%) men had multiple cancers with a solitary significant tumour focus. Thus, 173 out of 525 (33%) men had tumours potentially suitable for focal therapy. The majority of these were small, well-differentiated lesions that appeared to be pathologically insignificant (38–66%). Criteria used to select patients for focal prostatic ablation underestimated the cancer's significance in 26% (34 out of 130) of men and resulted in overtreatment in more than half. Only 18% (24 out of 130) of men presumed eligible for focal therapy, actually had significant solitary lesions.

Conclusion:

Focal therapy appears inappropriate for the majority of men presenting with prostate-specific antigen-detected localised prostate cancer. Unifocal prostate cancers suitable for focal ablation are difficult to identify pre-operatively using biopsy alone. Most lesions meeting criteria for focal ablation were either more aggressive than expected or posed little threat of progression.

Pros and cons of focal therapy for localised prostate cancer

In prostate cancer, an interesting and intriguing option to overcome the risks of whole-gland treatment is focal therapy, with the aim of eradicating known cancer foci and reducing collateral damages to the structures essential for maintaining normal urinary and sexual function. Ablation of all known lesions would favorably alter the natural history of the cancer without impacting health-related quality of life and allows for safe retreatment with repeated focal therapy or whole-gland approaches if necessary. Our objective is to reassess the possibilities and criticisms of such procedure: the rationale for focal therapy and the enthusiasm come from the success of conservative approaches in treating other malignancies and in the high incidence of overtreatment introduced by prostate cancer screening programs. One of the challenges in applying such an approach to the treatment of prostate cancer is the multifocal nature of the disease and current difficulties in accurate tumor mapmaking.

Are we able to correctly identify prostate cancer patients who could be adequately treated by focal therapy?

INTRODUCTION AND OBJECTIVE

Because of the improvements on detection of early stage prostate cancer over the last decade, focal therapy for localized prostate cancer (PC) has been proposed for patients with low-risk disease. Such treatment would allow the control of cancer, thereby diminishing side effects, such as urinary incontinence and sexual dysfunction, which have an enormous impact on quality of life. The critical issue is whether it is possible to preoperatively predict clinically significant unifocal or unilateral prostate cancer with sufficient accuracy. Our aim is to determine whether there is any preoperative feature that can help select the ideal patient for focal therapy.

MATERIAL AND METHODS

A total of 599 patients who underwent transrectal ultrasound (TRUS)-guided prostate biopsy followed by radical prostatectomy to treat PC were examined in our laboratory between 2001 and 2009. We established very restricted criteria to select patients with very-low-risk disease for whom focal therapy would be suitable (only 1 biopsy core positive, tumor no larger than 80% of a single core, no perineural invasion, PSA serum level < 10 ng/ml, Gleason score < 7 and clinical stage T1c, T2a-b). We defined 2 groups of patients who would be either adequately treated or not treated by focal therapy. The primary endpoint was the evaluation of preoperative features in order to identify which parameters should be considered when choosing good candidates for focal therapy.

RESULTS

Fifty-six out of 599 patients met our criteria. The mean age was 59 years, and the mean number of biopsy cores was 14.4. Forty-seven (83.9%) were staged T1c, and 9 (16.1%) were staged T2a-b. Forty-four (78.6%) patients could be considered to have been adequately treated by focal therapy, and 12 (21.4%) could not. There was no statistical difference between the 2 groups considering age, clinical stage, PSA levels, Gleason score, and tumor volume in the biopsy. All 12 patients who could be considered inadequately treated had a bilateral, significant secondary tumor, 58.3% had Gleason ≥ 7, and 25% were staged pT3.

CONCLUSION

Although focal therapy might be a good option for patients with localized prostate cancer, we are so far unable to select which of them would benefit from it based on preoperative data, even using very restricted criteria, and a considerable proportion of men would still be left undertreated.

Repeat prostate biopsies predict location of index cancer in an active surveillance cohort

OBJECTIVE

• To evaluate the ability of repeat prostate biopsies to determine the location of the index cancer for men on prostate cancer surveillance.

PATIENTS AND METHODS

• Forty-five men on active surveillance had a record of the locations of their positive diagnostic biopsy, repeat surveillance biopsy and index cancer (i.e. largest cancer) from prostatectomy specimens. • Logistic regression analysis was used to evaluate the association between two consecutive needle biopsies showing cancer in an identical location and the outcome of finding the index cancer at the same location as the initial diagnostic biopsy.

RESULTS

• Eighteen of 45 (40%) men ultimately had an index cancer at the same location as their diagnostic biopsy. • Thirteen men had two consecutive biopsies that showed cancer at the same location each time; nine of these men ultimately had an index cancer at that same location. • In multivariable logistic regression analysis of men with at least two biopsies, having two initial consecutive biopsies with the same location increased the odds (odds ratio 5.9; 95% CI 1.1-31, P= 0.037) of having an index cancer at the same location as the initial biopsy in a cohort of men on active surveillance.

CONCLUSIONS

• A substantial proportion of men in an active surveillance cohort who undergo prostatectomy ultimately have evidence of an index cancer at the same location as their initial biopsy. • This is more likely to be the case when a repeat biopsy shows evidence of cancer at the same location.

Beyond diagnosis: evolving prostate biopsy in the era of focal therapy

Despite decades of use as the “gold standard” in the detection of prostate cancer, the optimal biopsy regimen is still not universally agreed upon. While important aspects such as the need for laterally placed biopsies and the importance of apical cancer are known, repeated studies have shown significant patients with cancer on subsequent biopsy when the original biopsy was negative and an ongoing suspicion of cancer remained. Attempts to maximise the effectiveness of repeat biopsies have given rise to the alternate approaches of saturation biopsy and the transperineal approach. Recent interest in focal treatment of prostate cancer has further highlighted the need for accurate detection of prostate cancer, and in response, the introduction of transperineal template-guided biopsy. While the saturation biopsy approach and the transperineal template approach increase the detection rate of cancer in men with a previous negative biopsy and appear to have acceptable morbidity, there is a lack of clinical trials evaluating the different biopsy strategies. This paper reviews the evolution of prostatic biopsy and current controversies.

Tumor focality in prostate cancer: implications for focal therapy

In recent years, there has been a growing interest in focal treatment for prostate cancer. Although widely used for the treatment of tumors of the breast and kidney, focal treatment for prostate cancer remains a controversial area. Criticism of focal prostate therapy has been based on the fact that prostate cancer is a multifocal disease. Until now, little attention has been paid to distinguishing between men with unifocal and those with multifocal disease because such information has little clinical relevance when treatment is aimed at the whole gland irrespective of the volume or number of cancers in the prostate. In this Review, we summarize existing knowledge and examine the issue of prostate cancer focality in the context of focal treatment.

The role of transrectal saturation biopsy in tumour localization: pathological correlation after retropubic radical prostatectomy and implication for focal ablative therapy

OBJECTIVE

• To evaluate the accuracy of an initial 24-core prostate biopsy scheme (PBx24) in predicting unilateral prostate cancer (PCa) in radical prostatectomy (RP) specimens.

PATIENTS AND METHODS

• Between 2005 and 2008, 203 consecutive patients underwent PBx24 followed by RP for PCa. The area under the curve (AUC) was used to evaluate the accuracy of unilateral PCa on PBx24 to predict unilateral PCa in RP specimens. • The positive predictive value (PPV) and negative predictive value (NPV) were also calculated. Moreover, in patients with unilateral PCa on biopsy, univariable and multivariable logistic regression analyses tested the relationship between the presence of unilateral PCa in an RP specimen and the variables: age, prostate-specific antigen (PSA), total prostate volume, clinical stage, primary Gleason grade, secondary Gleason grade and the number of positive cores.

RESULTS

• PCa cores were unilateral in 115 patients (56.7%) on biopsy. Of those, only 26 (22.6%) had unilateral PCa in the RP specimen (AUC, 72.9%; PPV, 22.6%; NPV, 98.8%). In patients with clinically low-risk tumours, only 17 of 63 (27%) had a unilateral PCa on PBx24 and in the RP specimen (AUC, 59.1%; PPV, 27.0%; NPV, 100.0%). • None of the examined variables was an independent predictor of the presence of unilateral PCa in the RP specimen (all P > 0.05).

CONCLUSIONS

• Initial PBx24 is not sufficiently accurate to be dependable as a method of predicting tumour laterality in RP specimens. Therefore, the use of PBx24 to guide hemi-ablation therapy of PCa may lead to mistreatment in a considerable proportion of patients. • Moreover, none of the routinely available clinical and pathological characteristics appears to improve the ability of unilateral PCa on biopsy to predict unilateral PCa in the RP specimen.

Screening, risk assessment, and the approach to therapy in patients with prostate cancer

The major challenge in prostate cancer is to identify patients at higher risk of death and to distinguish them from those more likely to die from other causes. Stratification of patients into risk groups can be used to guide management decisions at each disease stage. This review discusses the measures, tools, and nomograms available for risk assessment in prostate cancer. For patients with localized hormone-sensitive disease, the choice is between active surveillance and radical treatment, with focal therapy an emerging option. Current guidelines recommend treatment of patients with a life expectancy ≥10 years, although active surveillance is being used with increasing frequency for low-risk patients, even with a long life expectancy. A number of risk stratification methods have been devised to assess the risk of biochemical recurrence (BCR) after treatment, with prostate-specific antigen (PSA) level, Gleason score, clinical stage, and tumor mass/volume all shown to be predictive of BCR. Among men with BCR after treatment, PSA doubling time (PSADT) was the best predictor of further progression. Although studies in patients with castration-resistant prostate cancer have shown that PSA level and PSADT are associated with a risk of developing metastatic disease, there is currently no clear surrogate for disease progression or overall survival for this patient group and no standard second- or third-line therapy after progression on first-line chemotherapy. The use of newly developed risk-stratification models and markers of disease progression should assist in the earlier identification of disease progression, allowing the optimal treatment of such patients.

Intensity-modulated radiotherapy for prostate cancer implementing molecular imaging with 18F-choline PET-CT to define a simultaneous integrated boost

PURPOSE

To report the own experience with 66 patients who received 18F-choline PET-CT (positron emission tomography-computed tomography) for treatment planning.

PATIENTS AND METHODS

Image acquisition followed 1 h after injection of 178-355 MBq (18)F-choline. An intraprostatic lesion (GTV(PET) [gross tumor volume]) was defined by a tumor-to-background SUV (standard uptake value) ratio > 2. A dose of 76 Gy was prescribed to the prostate in 2-Gy fractions, with a simultaneous integrated boost up to 80 Gy.

RESULTS

A boost volume could not be defined for a single patient. One, two and three or more lesions were found for 36 (55%), 22 (33%) and seven patients (11%). The lobe(s) with a positive biopsy correlated with a GTV(PET) in the same lobe in 63 cases (97%). GTV(PET) was additionally defined in 33 of 41 prostate lobes (80%) with only negative biopsies. GTV(PET), SUV(mean) and SUV(max) were found to be dependent on well-known prognostic risk factors, particularly T-stage and Gleason Score. In multivariate analysis, Gleason Score > 7 resulted as an independent factor for GTV(PET) > 8 cm(3) (hazard ratio 5.5; p = 0.02) and SUV(max) > 5 (hazard ratio 4.4; p = 0.04). Neoadjuvant hormonal treatment (NHT) did not affect SUV levels. The mean EUDs (equivalent uniform doses) to the rectum and bladder (55.9 Gy and 54.8 Gy) were comparable to patients (n = 18) who were treated in the same period without a boost (54.3 Gy and 55.6 Gy).

CONCLUSION

Treatment planning with (18)F-choline PET-CT allows the definition of an integrated boost in nearly all prostate cancer patients - including patients after NHT - without considerably affecting EUDs for the organs at risk. GTV(PET) and SUV levels were found to be dependent on prognostic risk factors, particularly Gleason Score.

Diffusion-weighted magnetic resonance imaging in patients with unilateral prostate cancer on extended prostate biopsy: predictive accuracy of laterality and implications for hemi-ablative therapy

PURPOSE

We evaluated the ability of extended prostate biopsy to detect unilateral prostate cancer and assessed the incremental diagnostic benefit of diffusion-weighted magnetic resonance imaging to predict unilateral prostate cancer.

MATERIALS AND METHODS

A total of 130 patients with prostate cancer detected by extended pattern prostate biopsy underwent magnetic resonance imaging before radical prostatectomy. Tumor laterality on extended prostate biopsy was compared with the corresponding lobe on the radical prostatectomy specimen. In patients with unilateral prostate cancer on biopsy we calculated the probability of a tumor in the contralateral lobe on magnetic resonance images and calculated area under the receiver operating characteristics curve. We compared the diagnostic accuracy of combined T2-weighted and diffusion-weighted magnetic resonance images to that of T2-weighted magnetic resonance images alone.

RESULTS

Of the 130 patients 88 (67.7%) had unilateral disease on extended prostate biopsy. Radical prostatectomy pathology showed that 19% of these patients had unilateral disease but 81% had bilateral disease. Area under the receiver operating characteristics curve of combined diffusion-weighted and T2-weighted magnetic resonance imaging was greater than that of T2-weighted magnetic resonance imaging alone (0.814, 95% CI 0.716-0.889 vs 0.510, 95% CI 0.401-0.618). T2-weighted plus diffusion-weighted magnetic resonance imaging had significantly higher sensitivity (84.1% vs 61.9%, p = 0.003) and specificity (72.0% vs 36.0%, p = 0.004) to predict cancer in the contralateral lobe than T2-weighted magnetic resonance alone.

CONCLUSIONS

Extended prostate biopsy cannot accurately determine prostate cancer unilaterality. Diffusion-weighted magnetic resonance combined with T2-weighted magnetic resonance imaging has an incremental diagnostic benefit to predict unilateral prostate cancer.

Candidate selection for prostate cancer focal therapy

Focal therapy has emerged as a potential treatment paradigm for men with localized prostate cancer, because it serves as a medium between the ambiguity of surveillance and the potential reduction of quality of life observed with radical treatment. Candidate selection remains the major challenge of implementing focal therapy in clinical practice. While focal therapy is potentially widely applicable, there is general consensus that initial efforts to initiate focal therapy protocols in practice should be limited to men with disease features that are low to low-intermediate risk, thereby limiting the likelihood of early systemic failure. Selection of candidates is first dependent on the intent of focal therapy. Curative intent focal therapy is limited to a small number of men with isolated, low-risk, unifocal, or unilateral disease. In men for whom local control-and potential prolongation of the natural history of disease-is desired, mapping strategies would focus on identification of the dominant site of disease and ruling out high-risk features. Tools such as conventional transrectal biopsy, transperineal saturation biopsy, and prostate MRI all have relative merits and shortcomings. While ultimately limitation of biopsy is desirable through combinations of transrectal biopsy and imaging, for now, limitations of conventional imaging modalities make it likely that most men will need transperineal saturation biopsy before inclusion in focal therapy protocols.

Predicting the probability of significant prostate cancer in Japanese men with serum prostate-specific antigen less than 10 ng/mL: development of a novel pre-biopsy nomogram

OBJECTIVES

To develop and assess a new nomogram incorporating pre-biopsy clinical data to predict significant prostate cancer in Japanese men with a serum prostate-specific antigen (PSA) level of less than 10 ng/mL.

METHODS

We collected pre-biopsy data from 620 men with a serum total PSA of less than 10 ng/mL. They included 491 men with a negative biopsy and 129 men who were confirmed to have histological prostate cancer and subsequently underwent radical prostatectomy. Clinically significant tumors were defined as those with a tumor volume larger than 0.5 mL and/or a Gleason score of 7 or more.

RESULTS

One hundred and seven prostatectomy patients had clinically significant cancers. Stepwise multivariate logistic regression analysis showed that digital rectal examination findings, PSA adjusted for transition zone volume and free-to-total PSA ratio were the significant independent predictors of significant cancers (P < 0.0001). Using these pre-biopsy independent factors, a nomogram was developed to predict significant cancers. According to a receiver operating characteristics analysis, the nomogram showed an area under the curve of 0.831.

CONCLUSION

This represents the first nomogram to predict the probability of clinically significant cancers before biopsy. This tool is most likely to be useful in the management of patients with moderate to elevated PSA.

Focal treatment or observation of prostate cancer: pretreatment accuracy of transrectal ultrasound biopsy and T2-weighted MRI

OBJECTIVES

To test the hypothesis that men with prostate cancer (PCA) and preoperative disease features considered favorable for focal treatment would be accurately characterized with transrectal biopsy and prostate magnetic resonance imaging (MRI) by performing a retrospective analysis of a selected cohort of such patients treated with radical prostatectomy (RP).

METHODS

A total of 202 patients with PCA who had preoperative MRI and low-risk biopsy criteria (no Gleason grade 4/5, 1 involved core, < 2 mm, PSA density < or = 0.10, clinical stage < or = T2a) were included in the study. Indolent RP pathology was defined as no Gleason 4/5, organ confined, tumor volume < 0.5 mL, and negative surgical margins. MRI ability to locate and determine the tumor extent was assessed.

RESULTS

After RP, 101 men (50%) had nonindolent cancer. Multifocal and bilateral tumors were present in 81% and 68% of patients, respectively. MRI indicated extensive disease in 16 (8%). MRI sensitivity to locate PCA ranged from 2% to 20%, and specificity from 91% to 95%. On univariate analysis, MRI evidence of extracapsular extension (P = .027) and extensive disease (P = .001) were associated with nonindolent cancer. On multivariate analysis, only the latter remained as significant predictor (P = .0018).

CONCLUSIONS

Transrectal biopsy identified men with indolent tumors favorable for focal treatment in 50% of cases. MRI findings of extracapsular extension and extensive tumor involving more than half of the gland are associated with unfavorable features, and may be useful in excluding patients from focal treatment. According to these data, endorectal MRI is not sufficient to localize small tumors for focal treatment.

Current status of MRI for the diagnosis, staging and prognosis of prostate cancer: implications for focal therapy and active surveillance

PURPOSE OF REVIEW

To review the current status of MRI techniques in identification of organ-confined prostate cancer with a focus on their implication for focal therapy and active surveillance.

RECENT FINDINGS

MRI is currently focusing on intraprostatic prostate cancer identification and at 1.5T, it provides excellent imaging of the whole gland including the challenging anterior part. Improvements in accuracy for cancer detection and volume estimation result from dynamic contrast-enhanced and diffusion-weighted MRI sequences. 3T MRI might improve cancer identification. Histological correlations showed high sensitivity and specificity for significant volume cancers larger than 0.5 cm3. Important knowledge on modelling of cancer morphology such as zone of origin and intraprostatic patterns of spread at histopathology was made available for imaging interpretation and treatment planning decision. MRI results allow focused use of biopsy which led to better cancer characterization such as extent and grade. Ongoing focal therapy protocols and active surveillance treatments should benefit from these imaging advances.

SUMMARY

At present, high-resolution MRI with pelvic coil appears to offer the most readily available and useful imaging. Future studies should work towards helping define standard, reproducible approaches to imaging and image reporting for research and clinical practice.

Patient selection for focal therapy of localized prostate cancer

PURPOSE OF REVIEW

Prostate-specific antigen screening has led to a dramatically increased detection of low-grade, small-volume, organ-confined tumors. On the basis of concerns regarding overtreatment of biologically indolent cancers, focal ablative therapy has been introduced as an alternative to radical therapy or active surveillance. Because a critical requirement of focal therapy is appropriate patient selection, we review the pathologic characteristics of localized prostate cancer and methods to identify patients likely to have low-risk disease.

RECENT FINDINGS

Up to 33% of patients undergoing radical prostatectomy have unilateral, low-grade, organ-confined tumors on final pathology. Standard diagnostic methods such as ultrasound-guided biopsies may not be adequate to reliably identify these patients. Early data on three-dimensional transperineal and transrectal mapping biopsies have suggested an increased ability to precisely localize and characterize low-grade tumors. The addition of multisequence MRI and spectroscopy to standard diagnostic techniques is under study and may eventually further augment disease characterization.

SUMMARY

Appropriate selection criteria for focal therapy are evolving, and diagnostic techniques widely vary. Further study of extensive mapping biopsies, imaging techniques, and biomarkers are mandatory to improve the recognition and characterization of patients with biologically indolent lesions and better inform their treatment decision making.

Can the conventional sextant prostate biopsy accurately predict unilateral prostate cancer in low-risk, localized, prostate cancer?

We evaluate the reliability of routine sextant prostate biopsy to detect unilateral lesions. A total of 365 men with complete records including all clinical and pathologic variables who underwent a preoperative sextant biopsy and subsequent radical prostatectomy (RP) for clinically localized prostate cancer at our medical center between January 1996 and December 2006 were identified. When the sextant biopsy detects unilateral disease, according to RP results, the NPV is high (91%) with a low false negative rate (9%). However, the sextant biopsy has a PPV of 28% with a high false positive rate (72%). Therefore, a routine sextant prostate biopsy cannot provide reliable, accurate information about the unilaterality of tumor lesion(s).

WITHDRAWN: Can the conventional sextant prostate biopsy reliably diagnose unilateral prostate cancer in low-risk, localized, prostate cancer?

The authors hereby retract the e-publication dated 13 May 2008 and entitled, 'Can the conventional sextant prostate biopsy reliably diagnose unilateral prostate cancer in low-risk, localized, prostate cancer?' The authors are submitting a revised version with the same title. This article's statistics were performed for predicting bilateral prostate cancer outcomes. The article was written to help predict unilateral prostate cancer. Although the statistical numbers are correct, they are backwards. We apologize that the statistics indicate a contrary outcome (eg predicting bilateral cancer instead of unilateral disease).