Changing the referral criteria for bone scan in newly diagnosed prostate cancer patients

Measurements of peri-prostatic adipose tissue by MRI predict bone metastasis in patients with newly diagnosed prostate cancer

Objectives

To investigate the role of MRI measurements of peri-prostatic adipose tissue (PPAT) in predicting bone metastasis (BM) in patients with newly diagnosed prostate cancer (PCa).

Methods

We performed a retrospective study on 156 patients newly diagnosed with PCa by prostate biopsy between October 2010 and November 2022. Clinicopathologic characteristics were collected. Measurements including PPAT volume and prostate volume were calculated by MRI, and the normalized PPAT (PPAT volume/prostate volume) was computed. Independent predictors of BM were determined by univariate and multivariate logistic regression analysis, and a new nomogram was developed based on the predictors. Receiver operating characteristic (ROC) curves were used to estimate predictive performance.

Results

PPAT and normalized PPAT were associated with BM (P<0.001). Normalized PPAT positively correlated with clinical T stage(cT), clinical N stage(cN), and Grading Groups(P<0.05). The results of ROC curves indicated that PPAT and normalized PPAT had promising predictive value for BM with the AUC of 0.684 and 0.775 respectively. Univariate and multivariate analysis revealed that high normalized PPAT, cN, and alkaline phosphatase(ALP) were independently predictors of BM. The nomogram was developed and the concordance index(C-index) was 0.856.

Conclusions

Normalized PPAT is an independent predictor for BM among with cN, and ALP. Normalized PPAT may help predict BM in patients with newly diagnosed prostate cancer, thus providing adjunctive information for BM risk stratification and bone scan selection.

Validating the screening criteria for bone metastases in treatment-naïve unfavorable intermediate and high-risk prostate cancer - the prevalence and location of bone- and lymph node metastases

OBJECTIVE

The European Association of Urology (EAU) recommends a bone scan for newly diagnosed unfavorable intermediate- and high-risk prostate cancer. We aimed to validate the screening criteria for bone metastases in patients with treatment-naïve prostate cancer.

METHODS

This single-center retrospective study included all patients with treatment-naïve unfavorable intermediate- or high-risk prostate cancer. All underwent MRI of the lumbar column (T2Dixon) and pelvis (3DT2w, DWI, and T2 Dixon). The presence and location of lymph node and bone metastases were registered according to risk groups and radiological (rad) T-stage. The risk of lymph node metastases was assessed by odds ratio (OR).

RESULTS

We included 390 patients, of which 68% were high-risk and 32% were unfavorable intermediate-risk. In the high-risk group, the rate of regional- and non-regional lymph node metastases was 11% and 6%, respectively, and the rate of bone metastases was 10%. In the unfavorable intermediate-risk group, the rate of regional- and non-regional lymph node metastases was 4% and 0.8%, respectively, and the rate of bone metastases was 0.8%. Metastases occurred exclusively in the lumbar column in 0.5% of all patients, in the pelvis in 4%, and the pelvis and lumbar column in 3%. All patients with bone metastases had radT3-4, and patients with radT3-4 showed a four-fold increased risk of lymph node metastases (OR 4.48, 95% CI: 2.1-9.5).

CONCLUSION

Bone metastases were found in 10% with high-risk prostate cancer and 0.8% with unfavorable intermediate-risk. Therefore, we question the recommendation to screen the unfavorable intermediate-risk group for bone metastases.

KEY POINTS

• The rate of bone metastases was 10% in high-risk patients and 0.8% in the unfavorable intermediate-risk group. • The rate of lymph-node metastases was 17% in high-risk patients and 5% in the unfavorable intermediate-risk group. • No bone metastases were seen in radiologically localized disease.

Segmented linear correlations between bone scan index and prostate cancer biomarkers, alkaline phosphatase, and prostate specific antigen in patients with a Gleason score ≥7

Technetium-99m methyl diphosphonate bone scintigraphy is relatively easily accessible for detecting bone metastases in prostate cancer patients. However, it is subjective and can be challenging to compare images taken at different time points. The bone scan index (BSI) is a more objective evaluation and allows for better comparison of images. Its correlation with other biomarkers of prostate cancer metastases such as prostate specific antigen (PSA) and alkaline phosphatase (ALP) is not clearly understood. This study thus aimed to compare the BSI correlation to PSA against that of BSI to ALP levels in patients with a Gleason score ≥7.A retrospective analysis of the medical records of 50 prostate cancer patients with a Gleason score of ≥7 referred for a bone scan between January 1, 2015 and December 31, 2018 was undertaken. Bone scans were interpreted visually, and using a semi-automated computer programme to quantify the BSI and its relation to PSA and ALP measurements.For the metastasis positive measurements, there was a statistically significant moderate positive overall linear correlation between BSI and PSA. For ALP and BSI, there were 2 segmented strong positive linear relationships between them. The first segment consisted of ALP < 375 IU/L and BSI >10%, where ALP and BSI were strongly and positively correlated. The other segment tended to have generally low BSI measurements (<10%) and also had a strong and positive correlation.The BSI was found to be better linearly correlated with ALP than PSA.

Evaluation of selective bone scan staging in prostate cancer - external validation of current strategies and decision-curve analysis

BACKGROUND

Recommendations for staging newly diagnosed prostate cancer patients vary between guidelines and literature.

METHODS

Our objective was to validate and compare prediction models selecting newly diagnosed prostate cancer patients for bone scan staging. To achieve this, we validated eleven models in a population-based cohort of 10,721 patients diagnosed with prostate cancer between 2005 and 2019. The primary outcome was net-benefit. This was assessed at different balances of conservatism and tolerance, represented by preference ratio and number-willing-to-test (NWT). Secondary outcomes included calibration slope, calibration-in-the-large (intercept), and discrimination measured by Area-under-the-receiver-operator-characteristics curve (AUC).

RESULTS

For preference ratios less than 1:39 (NWT greater than 40), scanning everyone provided greater net-benefit than selective staging. For preference ratios 1:39 to 3:97 (NWT 33-40), the European Association of Urology (EAU) 2020 guideline recommendation was the best approach. For preference ratios 3:97-7:93 (NWT 14-33), scanning EAU high-risk patients only was preferable. For preference ratios 7:93-1:9 (NWT 10-13), scanning only Gnanapragasam Group 5 patients was best. All models had similar fair discrimination (AUCs 0.68-0.80), but most had poor calibration.

CONCLUSIONS

We identified three selective staging strategies that outperformed all other approaches but did so over different ranges of conservatism and tolerance. Scanning only EAU high-risk patients provided the greatest net-benefit over the greatest range of preference ratios and scenarios, but other options may be preferable depending upon the local healthcare system's degree of conservatism and tolerance.

Staging 68 Ga-PSMA PET/CT in 963 consecutive patients with newly diagnosed prostate cancer: incidence and characterization of skeletal involvement

PURPOSE

The aim of the study was to elaborate the incidence and type of skeletal involvement in a large cohort of patients with newly diagnosed prostate cancer (PCa) referred for Ga-68 PSMA-11 PET/CT staging in a single center.

METHODS

Study cohort included 963 consecutive patients with newly diagnosed PCa referred for Ga-68 PSMA-11 PET/CT study for staging. The incidence of bone involvement, type of bone metastases, and extent of disease were determined and correlated with the ISUP Grade Group (GG) criteria and PSA levels.

RESULTS

Bone metastases were found in 188 (19.5%) of 963 patients. Bone metastases were found in 10.7% of patients with PSA < 10 ng/dL and in 27.4% of patients with PSA > 10 ng/dL and in 6.1% of patients with GG ≤ 2/3 and in 8.9% of patients with GG 4/5. In 7.6% of the patients, skeletal involvement was extensive, while 11.9% of patients had oligometastatic disease. Osteoblastic type metastases were the most common type of bone metastases presented in 133 of the patients with malignant bone involvement (70.7%). More than half of them had only osteoblastic lesions (72 patients (38.3%)), while the other (61 patients (32.5%)) had also intramedullary and/or osteolytic type lesions. Intramedullary metastases were found in 97 patients (51.6%), while 41 (21.8%) of them were only intramedullary lesions. Osteolytic metastases were detected in 36 patients (19.2%), of which 8 were only osteolytic lesions.

CONCLUSION

Although traditionally bone metastases of PCa are considered osteoblastic, osteolytic and intramedullary metastases are common, as identified on PET with labeled PSMA. Skeletal spread may be present also in patients with GG ≤ 2/3 and PSA < 10 ng/dL.

18F-fluciclovine PET/CT detection of biochemical recurrent prostate cancer in patients with PSA levels <2.00 ng/mL

OBJECTIVE

To establish the detection rate of prostate cancer recurrence following definitive therapy by 18F-fluciclovine PET/computed tomography (CT) in patients with biochemical recurrence (BCR) and prostate-specific antigen (PSA) levels less than 2.00 ng/mL.

METHODS

In this retrospective study, 78 patients with a PSA level of less than 2.00 ng/mL were selected from the 211 patients who underwent at least one 18F-fluciclovine PET/CT scan at our institution for the detection of biochemical recurrent prostate cancer between April 2017 and December 2018. Inherent differences in the characteristics of patients with and without a positive scan were investigated for possible associations using multivariable analysis.

RESULTS

One or more positive sites of recurrence were identified in 44 out of 78 patients (56.4%). Patients with a Gleason score between 8 and 10 were more likely to have a positive scan compared to patients with Gleason scores of 6-7 [adjusted odds ratio: 3.53, 95% confidence interval (1.13-10.99), P = 0.03]. No other significant association was found between PSA, T classification, and detection rate.

CONCLUSION

18F-fluciclovine PET/CT demonstrated a detection rate of 56.4% among patients with a PSA below 2.0 ng/mL. The results of this study support the use of 18F-fluciclovine PET/CT for the detection of recurrent prostate cancer at lower PSA levels, even at PSA levels less than 0.5 ng/mL.

A Radiomics nomogram for predicting bone metastasis in newly diagnosed prostate cancer patients

PURPOSE

To establish and validate a radiomics nomogram for predicting bone metastasis (BM) in patients with newly diagnosed prostate cancer (PCa).

METHOD

One-hundred and sixteen patients (training cohort: n = 81; validation cohort: n = 35) who underwent prostate MR imaging and confirmed by pathology with newly diagnosed PCa from January 2014 to January 2019 were enrolled. Radiomic features were extracted from diffusion-weighted, axial T2-weighted fat suppression, and dynamic contrast-enhanced T1-weighted MRI of each patient. Dimension reduction, feature selection, and radiomics feature construction were performed using the least absolute shrinkage and selection operator (LASSO) regression. Combined with independent clinical risk factors, a multivariate logistic regression model was used to establish a radiomics nomogram. Nomogram calibration and discrimination were evaluated in training cohort and verified in the validation cohort. Finally, the clinical usefulness of the nomogram was estimated through decision curve analysis (DCA).

RESULTS

Radiomics signature consisting of 12 selected features was significantly correlated with bone status (P < 0.001 for both training and validation sets). The radiomics nomogram combined a radiomics signature from multiparametric MR images with independent clinic risk factors. The model showed good discrimination and calibration in the training cohort (AUC 0.93, 95% CI, 0.86 to 0.99) and the validation cohort (AUC 0.92, 95% CI, 0.84 to 0.99). DCA also demonstrated the clinical use of the radiomics model.

CONCLUSION

The radiomics nomogram, which incorporates the multiparametric MRI-based radiomics signature and clinical risk factors, can be conveniently used to promote individualized prediction of BM in patients with newly diagnosed PCa.

Circulating Tumor Cells as a Marker of Disseminated Disease in Patients with Newly Diagnosed High-Risk Prostate Cancer

The aim of this study was to investigate whether the enumeration of circulating tumor cells (CTCs) in blood can differentiate between true localized and metastatic prostate cancer. A cross-sectional study of 104 prostate cancer patients with newly diagnosed high-risk prostate cancer was conducted. In total, 19 patients presented metastatic disease and 85 were diagnosed with localized disease. Analyses included intergroup comparison of CTC counts, determined using the CellSearch® system, EPISPOT assay and GILUPI CellCollector®, and ROC analysis verifying the accuracy of CTC count as a maker of disseminated prostate cancer. The vast majority (94.7%) of patients with advanced-stage cancer tested positively for CTCs in at least one of the assays. However, significantly higher CTC counts were determined with the CellSearch® system compared to EPISPOT assay and GILUPI CellCollector®. Identification of ≥4 CTCs with the CellSearch® system was the most accurate predictor of metastatic disease (sensitivity 0.500; specificity 0.900; AUC (95% CI) 0.760 (0.613-0.908). Furthermore, we tried to create a model to enhance the specificity and sensitivity of metastatic prediction with CTC counts by incorporating patient's clinical data, including PSA serum levels, Gleason score and clinical stage. The composite biomarker panel achieved the following performance: sensitivity, 0.611; specificity, 0.971; AUC (95% CI), 0.901 (0.810-0.993). Thus, although the sensitivity of CTC detection needs to be further increased, our findings suggest that high CTC counts might contribute to the identification of high-risk prostate cancer patients with occult metastases at the time of diagnosis.

Development and validation of a prediction model for identifying men with intermediate- or high-risk prostate cancer for whom bone imaging is unnecessary: a nation-wide population-based study

Objective: To develop and validate a nomogram that identifies men for whom bone scan is unnecessary.Material and methods: The study datasets were derived from the National Prostate Cancer Register (NPCR) of Sweden. All men in the NPCR ≤80 years of age who were diagnosed with intermediate- or high-risk prostate cancer and who had pretreatment bone imaging (^99mTc MDP scintigraphy, plain x-ray, computed tomography, magnetic resonance imaging, and/or positron emission tomography fused with computed tomography) were included. Men diagnosed from 2015-2016 formed a development dataset and men diagnosed in 2017 formed a validation dataset. Outcome was metastasis on bone imaging as registered in NPCR. Multivariable logistic regression was used to develop a nomogram.Results: In the development dataset 482/5084 men (10%) had bone metastasis, the corresponding percentage in the validation dataset was 282/2554 (11%). Gleason grade group, clinical T stage, and prostate-specific antigen were included in the final model. Discrimination and calibration were satisfactory in both the development (AUC 0.80, 95% CI 0.78-0.82) and validation dataset (AUC 0.80, 95% CI, 0.77-0.82). Compared with using the EAU guidelines' recommendation for selecting men for imaging, using the nomogram with a cut-off at 4% chance of bone metastasis, would have avoided imaging in 519/2068 men (25%) and miss bone metastasis in 10/519 (2%) men in the validation dataset.Conclusion: By use of our nomogram, bone scans of men with prostate cancer can be avoided in a large proportion of men.

Practice patterns and outcomes of equivocal bone scans for patients with castration-resistant prostate cancer: Results from SEARCH

Objective

To review follow-up imaging after equivocal bone scans in men with castration resistant prostate cancer (CRPC) and examine the characteristics of equivocal bone scans that are associated with positive follow-up imaging.

Methods

We identified 639 men from five Veterans Affairs Hospitals with a technetium-99m bone scan after CRPC diagnosis, of whom 99 (15%) had equivocal scans. Men with equivocal scans were segregated into “high-risk” and “low-risk” subcategories based upon wording in the bone scan report. All follow-up imaging (bone scans, computed tomography [CT], magnetic resonance imaging [MRI], and X-rays) in the 3 months after the equivocal scan were reviewed. Variables were compared between patients with a positive vs. negative follow-up imaging after an equivocal bone scan.

Results

Of 99 men with an equivocal bone scan, 43 (43%) received at least one follow-up imaging test, including 32/82 (39%) with low-risk scans and 11/17 (65%) with high-risk scans (p = 0.052). Of follow-up tests, 67% were negative, 14% were equivocal, and 19% were positive. Among those who underwent follow-up imaging, 3/32 (9%) low-risk men had metastases vs. 5/11 (45%) high-risk men (p = 0.015).

Conclusion

While 19% of all men who received follow-up imaging had positive follow-up imaging, only 9% of those with a low-risk equivocal bone scan had metastases versus 45% of those with high-risk. These preliminary findings, if confirmed in larger studies, suggest follow-up imaging tests for low-risk equivocal scans can be delayed while high-risk equivocal scans should receive follow-up imaging.

Establishing a prediction model for prostate cancer bone metastasis

We collected clinical data from 308 prostate cancer (PCa) patients to investigate the clinical characteristics and independent risk factors of bone metastasis (BM) and to establish a prediction model for BM of PCa and determine the necessity of bone scans. Univariate and multivariate analyses were performed based on age, biopsy Gleason score (BGS), clinical tumor stage (cTx), total prostate specific antigen (tPSA), free prostate specific antigen (fPSA), fPSA/tPSA, prostate volume, alkaline phosphatase (ALP), serum calcium and serum phosphorus. Moreover, 80 of the 308 PCa patients had a PI-RADS v2 score and were analysed retrospectively. The univariate analysis showed that the BGS, cTx, tPSA, fPSA, prostate volume and ALP were significant. The multivariate logistic regression analysis showed significant differences among the BGS, cTx, tPSA and ALP. Four cases should be highly suspected with BM: (i) cTl-cT2, BGS ≤7, ALP >120 U/L and tPSA >90.64 ng/ml; (ii) cTl-cT2, BGS ≥8, and ALP >120 U/L; (iii) cT3-cT4, BGS ≤7, and ALP >120 U/L; and (iv) cT3-cT4 and BGS ≥8. After the PI-RADS v2 score was included in the model, the AUC of the prediction model rose from 0.884 (95% CI: 0.813-0.996) to 0.934 (95% CI: 0.883-0.986). This model may help determine the necessity of bone scans to diagnose BM for PCa patients.

Reporting and Handling of Indeterminate Bone Scan Results in the Staging of Prostate Cancer: A Systematic Review

Bone scintigraphy is key in imaging skeletal metastases in newly diagnosed prostate cancer. Unfortunately, a notable proportion of scans are not readily classified as positive or negative but deemed indeterminate. The extent of reporting of indeterminate bone scans and how such scans are handled in clinical trials are not known. A systematic review was conducted using electronic databases up to October 2016. The main outcome of interest was the reporting of indeterminate bone scans, analyses of how such scans were managed, and exploratory analyses of the association of study characteristics and the reporting of indeterminate bone scan results. Seventy-four eligible clinical trials were identified. The trials were mostly retrospective (85%), observational (95%), large trials (median 195 patients) from five continents published over four decades. The majority of studies had university affiliation (72%), and an author with imaging background (685). Forty-five studies (61%) reported an indeterminate option for the bone scan and 23 studies reported the proportion of indeterminate scans (median 11.4%). Most trials (44/45, 98%) reported how to handle indeterminate scans. Most trials (n = 39) used add-on supplementary imaging, follow-up bone scans, or both. Exploratory analyses showed a significant association of reporting of indeterminate results and number of patients in the study (p = 0.024) but failed to reach statistical significance with other variables tested. Indeterminate bone scan for staging of prostate cancer was insufficiently reported in clinical trials. In the case of indeterminate scans, most studies provided adequate measures to obtain the final status of the patients.

Incorporating multiparametric MRI staging and the new histological Grade Group system improves risk-stratified detection of bone metastasis in prostate cancer

BACKGROUND

There remains uncertainty on the need for bone staging in men with intermediate-risk prostate cancer. Current guidelines do not use mpMRI-staging information and rely on historic pathology grading.

METHODS

We investigated the ability of mpMRI and the new Grade Group system to better predict bone metastasis status in a retrospective cohort study of 438 men with prostate cancer undergoing baseline mpMRI and isotope bone scintigraphy (BS).

RESULTS

Including mpMRI-staging information significantly increased the specificity of bone metastasis detection from 3.0% to 24.2% (P<0.01) and sensitivity from 89.2% to 97.3%. The new Grade Group score demonstrated progressive increase in bone metastasis rates (P<0.001). A novel risk-stratification model combining Grade Groups, PSA and mpMRI staging shows promise in predicting bone metastasis and could potentially reduce BS usage by 22.4%-34.7%.

CONCLUSIONS

Incorporating the new Grade Group system and mpMRI staging more accurately identified bone metastatic risk and suggests men with Grade Group ⩽2 and/or without radiological T3 disease could safely avoid routine bone staging.

PSA doubling time as a screening test to predict bone scan positivity

Aims:

The aim of this article is to compare the effectiveness of PSADT and tPSA as predictors of bony metastases in patients’ with prostate cancer pre-definitive treatment, and help guide clinicians with the selective ordering of bone scans (BS).

Materials and methods:

PSA measurements were retrospectively analysed for 330 men with prostate cancer, investigated with BS between 2009 and 2012. Exclusion criteria included previous positive BS, other malignancy, prostatectomy/radiotherapy and any prostate-specific condition or treatment initiated between the PSA levels used to calculate doubling time. PSADT (months) = log2 × dT/(log(PSA1)–log(PSA2)).

Results:

A total of 273 men had negative BS and 57 had positive findings of metastases. Those with positive BS had significantly ( p < 0.05) faster median PSADT (4.5 vs 15.2 months) and higher median tPSA (94 vs 24.5 ng/ml). On ROC curve analysis, PSADT outperformed tPSA as a predictor of bone scan result, with area-under-the-curve of 0.85 vs 0.76 ( p = 0.02). A ratio (R) of tPSA/PSADT was no better than PSADT alone ( p = 0.65).

Conclusions:

In the absence of clinical reasons to suspect metastatic disease, it is appropriate to withhold ordering a BS for non-prostatectomy/radiotherapy patients with rising PSA levels, until the PSADT is less than 18 months. This has a sensitivity of 100.0% and a specificity of 41.0%.

A narrowing range of bone scan in newly diagnosed prostate cancer patients: A retrospective comparative study

OBJECTIVES

The objective of the following study is to clarify a suitable group whereby a bone scan could be spared at the initial staging of prostate cancer, we wished to identify the possible relationship between bone metastasis and clinical and pathological parameters including serum total prostate specific antigen (PSA) concentration, alkaline phosphatase (ALP), biopsy Gleason Score (GS), and percentage of pathological cores.

MATERIALS AND METHODS

We reviewed the results of 220 bone scintigraphies, which were done between January 1, 2011 and June 30, 2013 in patients with newly diagnosed prostate cancer. These parameters were evaluated together with standard clinicopathological data to determine the prediction ability of the bone scan by univariate and multivariate analyses.

RESULTS

Bone metastases were seen in 44 patients of all 220 patients (20%, 95% confidence interval, 17-24%). In univariate analysis, PSA and biopsy GS were useful in predicting the bone scan result, but ALP and percentage of pathological cores was not. In multivariate analysis, the single most useful parameter in predicting the bone scan result was PSA (P < 0.001).

CONCLUSIONS

A bone scan seems to be impractical in newly diagnosed prostate cancer patients with serum PSA level <20 ng/ml and GS up to seven and pre-treatment PSA is the best predictor of the need for the bone scan according to results of this study.

Is it safe to omit baseline bone scan for newly diagnosed prostate cancer patients?

OBJECTIVES

The aim of this study is to modify and validate a novel screening tool to determine the necessity of bone scans in Chinese PCa patients at the time of diagnosis.

METHODS

Five-hundred-and-one patients diagnosed with PCa between 2010 and 2013 at Zhongshan Hospital, Fudan University, were included in the study. All received bone scans using technetium 99m methylene diphosphonate (99mTc-​MDP) at the initial staging. Age, prostate-specific antigen (PSA) and alkaline phosphatase (ALP) at diagnosis, disease stage, and biopsy Gleason score were collected from all patients. Multivariate logistic regression analysis and discrimination analysis were performed. A validation analysis of this screening tool was performed by Shanghai Cancer Center, Fudan University.

RESULTS

Among the 501 patients, 84 (16.7%) of them had BM. The area under the ROC curve was 0.9006 (95% CI, 0.87-0.93). The sensitivity of the cut-off point was 94.1%, and the specificity was 58.3%. The validation analysis demonstrated an area under the ROC curve of 0.846 (95% CI, 0.805-0.887).

CONCLUSIONS

Study results demonstrated that a baseline bone scan can be safely omitted for cT1-T3 PCa patients who have a PSA ≤39 ng/ml and an ALP ≤88 IU/l. This novel screening tool may help determine the necessity of including a bone scan at the time of initial diagnosis of PCa.

Correlation between low Gleason score and prostate specific antigen levels with incidence of bone metastases in prostate cancer patients: when to omit bone scans?

BACKGROUND

To identify correlation and incidence of bone metastases in prostate cancer patient with low Gleason scores (GS) and prostate specific antigen (PSA) levels.

MATERIALS AND METHODS

This descriptive restrospective study covered patients with prostate cancer in Cipto Mangunkusumo Hospital in 2006-2011. Of a total of 478, those who had PSA values, histological examination, and bone scan were included, resulting in 358 eligible cases. PSA values were measured using the sandwich electrochemiluminescent immunoassay. Histological examination was graded according to Gleason's grading system and divided into 3 categories: well differentiated (GS ≤ 6), moderately differentiated (GS 7) and poorly differentiated (GS 8-10). Bone scans were performed using a radiopharmaceutical agent (Tc 99m methylenen diphosphonate) with images captured by gamma camera.

RESULTS

The mean age was 67.5 ± 7.8, mean GS was 7.7 ± 1.3 and median PSA was 56.9 (range: 0.48-17000 ng/ mL). There were 11 patients (3.0%) with positive bone scan with PSA<20 ng/mL and GS<8. Furthermore, there were 2 patients (0.6%) with GS ≤ 6 and PSA<10 ng/mL showing bone metastasis.

CONCLUSIONS

In our study, there were still small percentage of patients with bone metastasis even when low values of PSA (PSA<10 ng/mL) and GS (GS ≤ 6) were applied.

Application of bone scans for prostate cancer staging: Which guideline shows better result?

INTRODUCTION

We evaluated the accuracy of current guidelines by analyzing bone scan results and clinical parameters of patients with prostate cancer to determine the optimal guideline for predicting bone metastasis.

METHODS

We retrospectively analyzed patients who were diagnosed with prostate cancer and who underwent a bone scan. Bone metastasis was confirmed by bone scan results with clinical and radiological follow-up. Serum prostate-specific antigen, Gleason score, percent of positive biopsy core, clinical staging and bone scan results were analyzed. We analyzed diagnostic performance in predicting bone metastasis of the guidelines of the European Association of Urology (EAU), American Urological Association (AUA), and the National Comprehensive Cancer Network (NCCN) guidelines as well as Briganti's classification and regression tree (CART). We also compared the percent of positive biopsy core between patients with and without bone metastases.

RESULTS

A total 167 of 806 patients had bone metastases. Receiver operating curve analysis revealed that the AUA and EAU guidelines were better for detecting bone metastases than were Briganti's CART and NCCN. No significant difference was observed between AUA and EAU guidelines. Patients with bone metastases had a higher percent positive core than did patients without metastasis (the cut-off value >55.6).

CONCLUSION

The EAU and AUA guidelines showed better results than did Briganti's CART and NCCN for predicting bone metastasis in the enrolled patients. A bone scan is strongly recommended for patients who have a higher percent positive core and who meet the EAU and AUA guidelines.

Toward better use of bone scans among men with early-stage prostate cancer

OBJECTIVE

To evaluate the performance of published guidelines compared with that of current practice for radiographic staging of men with newly diagnosed prostate cancer.

MATERIALS AND METHODS

Using data from the Michigan Urological Surgery Improvement Collaborative clinical registry, we identified 1509 men diagnosed with prostate cancer from March 2012 through June 2013. Clinical data included age, prostate-specific antigen (PSA) level, Gleason score (GS), clinical trial stage, number of biopsy cores, and bone scan (BS) results. We then fit a multivariate logistic regression model to examine the association between clinical variables and the occurrence of bone metastases. Because some patients did not undergo BS, we used established methods to correct for verification bias and estimate the diagnostic accuracy of published guidelines.

RESULTS

Among 416 men who received a BS, 48 (11.5%) had evidence of bone metastases. Patients with bone metastases were older, with higher PSA levels and GS (all P <.05). In multivariate analyses, PSA (P <.001) and GS (P = .004) were the only independent predictors of positive BS. Guidelines from the American Urological Association and the National Comprehensive Cancer Network demonstrated similar performance in detecting bone metastases in our population, with fewer negative study results than those of the European Association of Urology guideline. Applying the American Urological Association recommendations (ie, image when PSA level >20 ng/mL or GS ≥ 8) to current clinical practice, we estimate that <1% of positive study results would be missed, whereas the number of negative study results would be reduced by 38%.

CONCLUSION

Based on current practice patterns, more uniform application of existing guidelines would ensure that BS is performed for almost all men with bone metastases, while avoiding many negative imaging studies.

Imaging of prostate carcinoma

BACKGROUND

Imaging of prostate carcinoma is an important adjunct to clinical evaluation and prostate specific antigen measurement for detecting metastases and tumor recurrence. In the past, the ability to assess intraprostatic tumor was limited.

METHODS

Pertinent literature was reviewed to describe the capabilities and limitations of the currently available imaging techniques for assessing prostate carcinoma. Evaluation of primary tumor and metastatic disease by ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine techniques is discussed.

RESULTS

Ultrasonography and MRI have limited usefulness for local staging of prostate cancer because of suboptimal sensitivity and specificity for identifying tumor extent and capsular penetration. Additional MRI techniques such as magnetic resonance-based perfusion imaging, diffusion imaging, and spectroscopy may provide incremental benefit. CT and bone scanning provide an assessment of metastatic disease but are also limited by the poor sensitivity of lymph node size as a criterion for detecting metastases. Novel imaging techniques such as hybrid imaging devices in the form of single-photon emission CT/CT gamma cameras, positron emission tomography/CT cameras, and, in the near future, positron emission tomography/MRI combined with tumor specific imaging radiotracers may have a significant impact on tumor staging and treatment response.

CONCLUSIONS

Cross-sectional imaging and scintigraphy have an important role in assessing prostate carcinoma metastases and treatment response. Increasingly, the incremental value of primary tumor imaging through MRI is being realized.

Predicting the risk of bone metastasis in prostate cancer

The ability to identify prostate cancer patients at 'high risk' for bone metastasis development could allow early selection of those most likely to benefit from interventions to prevent or delay bone metastasis. This review is aimed to identify potential predictors of risk for bone metastasis in newly diagnosed patients and in those who have already received treatment. At diagnosis, established predictors of prostate cancer aggressiveness (e.g. PSA level, clinical stage, Gleason score) can identify patients at risk for bone metastasis. Following treatment of the disease, increasing evidence suggests that absolute PSA levels and other measures of PSA kinetics are useful to aid prediction of bone metastasis risk in patients both with and without a history of ADT. However, which PSA parameter most accurately predicts risk and the cut-off values that should be employed are unclear. Inclusion of PSA parameters to identify a high risk population may be beneficial in whom bone-modifying treatments are being considered. Other novel (but unvalidated) biomarkers that potentially predict the development of bone metastases have been identified, although it is unclear whether they will have value as independent markers or when combined with other parameters (e.g. measures of PSA kinetics). Further prospective studies of PSA kinetics and other predictive markers are, therefore, required to define the optimal criteria for identifying patients at high risk of bone metastases and those who are most likely to benefit from intensive monitoring and therapeutic intervention.

Should bone scan be performed in Chinese prostate cancer patients at the time of diagnosis?

BACKGROUND

Prostate cancer (PCa) is increasingly being diagnosed in China. Early detection of bone metastases (BM) is critical in the management of patients with high-risk PCa. The aim of this study is to establish a screening model to determine if bone scan should be performed for BM in Chinese patients at the time when PCa is diagnosed.

MATERIALS AND METHODS

The study included 488 patients who were diagnosed with PCa between 2009 and 2011 at a single center. All patients received bone scans using technetium (99m)Tc methylene diphosphonate at the initial staging. If the bone scan finding was equivocal, computed tomography or magnetic resonance imaging was performed to confirm the diagnosis. Age, prostate-specific antigen (PSA) at diagnosis, clinical stage assigned according to the TNM 2002 staging system and biopsy Gleason score were collected in all patients. Multivariate logistic regression analysis was performed to identify statistically significant covariates and then receiver operating characteristic (ROC) curves were generated to identify optimal cut-off values. Using these cut-off values, a formula was devised to calculate an index value for BM screening at diagnosis. The model was cross-validated using the leave-one-out method.

RESULTS

Of the 488 patients, 65 patients (13.3%) had BM. The area under the ROC curve was 0.87 (95% confidence interval 0.83-0.94). The sensitivity of the cut-off point was 87.7% and the specificity was 73.1%. Bone scan is needed for all cT4 PCa patients, however, it is also advisable for cT1-T3 PCa patients who have a biopsy Gleason score ≤3 + 4 and a PSA >132.1, and for cT1-T3 patients having a Gleason score of ≥4 + 3 and PSA >44.5.

CONCLUSIONS

The regression model may help determine if bone scan is needed to detect BM from PCa at the time of diagnosis. The model was generated upon a single center experience. Further validation is needed in future studies.