A study on staging bone scans in newly diagnosed prostate cancer

Advances in high-risk localized prostate cancer: Staging and management

Nearly 15% of individuals with localized prostate cancer are identified as high risk for recurrence and progression of the disease, which is why the correct staging is vital for the definition of correct treatment-also developing novel therapeutic strategies to find a balance between getting better outcomes without sacrificing the quality of life (QoL). In this narrative review, we introduced the current standards of staging and primary treatment of high-risk localized prostate cancer (PCa), based on international guidelines and arguments in the debate, under the light of the most recent literature. It brings essential tools such as PSMA PET/CT and different nomograms (Briganti. MSKCC, Gandaglia) for accurate staging and selecting wisely the definitive therapy. Even though there is a broad discussion over the best local treatment in curative-intent treatment, it looks more important to define which patient profile would adapt correctly to every different treatment, highlighting the benefits and superior outcomes with multimodal treatment.

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.

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.

The prevalence and locations of bone metastases using whole-body MRI in treatment-naïve intermediate- and high-risk prostate cancer

Objective

The aim of this study was to assess the prevalence and distribution of bone metastases in treatment-naïve prostate cancer patients eligible for a metastatic workup using whole-body MRI, and to evaluate the results in light of current guidelines.

Methods

This single-institution, retrospective study included all patients with treatment-naïve prostate cancer referred to whole-body MRI during 2016 and 2017. All were eligible for a metastatic workup according to the guidelines: PSA > 20 ng/ml and/or Gleason grade group ≥ 3 and/or cT ≥ 2c and/or bone symptoms. The definition of a metastasis was descriptive and based on the original MRI reports. The anatomical location of metastases was registered.

Results

We included 161 patients with newly diagnosed prostate cancer of which 36 (22%) were intermediate-risk and 125 (78%) were high-risk. The median age and PSA were 71 years (IQR 64–76) and 13 ng/ml (IQR 8–28), respectively. Bone metastases were found in 12 patients (7%, 95% CI: 4–13), and all were high-risk with Gleason grade group ≥ 4. The pelvis was affected in 4 patients, and the spine + pelvis in the remaining 8. No patients demonstrated metastases to the spine without concomitant metastases in the pelvis. Limitations are the small number of metastases and retrospective design.

Conclusion

This study suggests that the overall prevalence of bone metastases using the current guidelines for screening is quite low. No metastases were seen in the case of Gleason grade group ≤ 3, and further studies should investigate if it necessary to screen non-high-risk patients.

Key Points

• The overall prevalence of bone metastases was 7% in the case of newly diagnosed intermediate- and high-risk prostate cancer.

• The prevalence in high-risk patients was 10%, and no metastases were seen in patients with Gleason grade group ≤ 3.

• The pelvic skeleton is the main site, and no metastases occurred in the spine without concomitant pelvic metastases.

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.

Predicting bone scan positivity after biochemical recurrence following radical prostatectomy in both hormone-naive men and patients receiving androgen-deprivation therapy: results from the SEARCH database

BACKGROUND

To evaluate the factors associated with positive bone scans after biochemical recurrence (BCR) following radical prostatectomy in both hormone-naive subjects and subjects after androgen-deprivation therapy (ADT).

METHODS

Retrospective analysis of 380 bone scans of 301 hormone-naive subjects and 214 bone scans of 137 subjects after ADT following BCR from the Shared Equal Access Regional Cancer Hospital database. Generalized estimating equations and local regression plots were used to evaluate bone scan positivity by patients' demographics, pathological features, PSA levels and kinetics.

RESULTS

Among hormone-naive subjects and subjects on ADT, bone scan positivity was seen in 24 (6%) and 65 (30%) subjects, respectively. In hormone-naive subjects, the higher prescan PSA, higher PSA velocity (PSAV) and shorter PSA doubling time (PSADT) were significantly associated with positive scans (P=0.008, P<0.001 and P<0.001, respectively). In subjects after ADT, the prescan PSA, PSAV and PSADT were significantly associated with positive scans (P=0.011, P<0.001 and P=0.002, respectively). Regression plots showed increased scan positivity with increasing PSA levels and shortening PSADT (all P<0.001) for both hormone-naive subjects and subjects after ADT. For a given PSA level and PSADT, subjects on ADT had higher bone scan positivity.

CONCLUSIONS

In both hormone-naive subjects and subjects after ADT, more aggressive and advanced disease identified by higher PSA levels, higher PSAV and shorter PSADT were associated with higher bone scan positivity. For the same PSA level and PSADT, subjects after ADT had higher bone scan positivity than hormone-naive subjects. Therefore, PSA levels and kinetics may be used as selection criteria for bone scan in these patients.

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

OBJECTIVES

The aim of this study was to correlate the prostate-specific antigen (PSA) level and Gleason score with staging bone scan result in patients with a new diagnosis of prostate cancer in order to establish the feasibility of implementing the European Association Urology guidelines, which state that a bone scan may not be indicated when PSA <20 in well-moderately differentiated tumours.

METHODS

We identified 633 patients retrospectively and 186 patients prospectively with a new diagnosis of prostate cancer undergoing a staging bone scan between March 2005 and January 2010. Patients were excluded if there was no Gleason score available or if the PSA level was checked over 3 months prior to bone scan. Bone scan results were analysed with respect to age, PSA level and Gleason score. In the case of an equivocal result, subsequent imaging was taken into consideration or the initial bone scan was re-reviewed. In persistently equivocal cases, all relevant imaging was assessed by a blinded panel of radiologists to allow a final decision to be made.

RESULTS

Of 672 patients aged 39-93 years (median 71 years), who fulfilled the inclusion criteria, 54 (8%) had evidence of bony metastases. PSA level and Gleason score were both independent predictors of bone scan positivity and their predictive value was additive p<0.01. None of the 357 patients with a PSA level of <20 and a Gleason score of <8 had a positive bone scan.

CONCLUSION

Staging bone scans in newly diagnosed prostate cancer patients with a PSA level of <20 and a Gleason score of <8 can be safely omitted, with these criteria having a negative predictive value of 100% in our series.