Prognostic Value of Automated Bone Scan Index in Men With Metastatic Castration-resistant Prostate Cancer Treated With Enzalutamide or Abiraterone Acetate

Bone scan index (BSI) scoring by using bone scintigraphy and circulating tumor cells (CTCs): predictive factors for enzalutamide effectiveness in patients with castration-resistant prostate cancer and bone metastases

Reports of Bone Scan Index (BSI) calculations as imaging biomarkers to predict survival in patients with metastatic castration-resistant prostate cancer (mCRPC) have been mainly from retrospective studies. To evaluate the effectiveness of enzalutamide (ENZ) in Japanese patients with mCRPC and bone metastases using BSI (bone scintigraphy) and circulating tumor cell (CTC) analysis. Prospective, single-arm study at Juntendo University affiliated hospitals, Japan. Patients were administered 160 mg ENZ daily, with 3 monthly assessments: BSI, prostate specific antigen (PSA), CTC and androgen receptor splicing variant-7 (AR-V7) status. Primary endpoint: BSI-decreasing rate after ENZ treatment. Secondary endpoints: PSA-decreasing rate and progression free survival (PFS). Statistical analyses included the Wilcoxon t-test, Cox proportional hazard regression analysis, and log-rank test. Median observation period: 17.9 months, and median PFS: 13.8 (2.0-43.9) months (n = 90 patients). A decrease in BSI compared to baseline as best BSI change on ENZ treatment was evident in 69% patients at the end of the observation period (29% patients showed a complete response, BSI 0.00). At 3 months 67% patients showed a ≥ 50% PSA reduction, and 70% after ENZ treatment. PSA decline (3 months) significantly associated with a prolonged median PFS: 18.0 (estimated) versus 6.4 months (HR 2.977 [95% CI 1.53-5.78], p = 0.001). Best BSI decline response significantly associated with a prolonged PFS: 18.1(estimated) versus 7.8 months (HR 2.045 [95% CI: 1.07-3.90], p = 0.029). CTC negative status (n = 20) significantly associated with a prolonged PFS: 13.4 [estimated] vs 8.6 months (HR 2.366, 95% CI 0.97-5.71, p = 0.041). CTC positive/AR-V7 positive status significantly associated with a shorter PFS: 5.9 months (HR 8.56, 95% CI 2.40-30.43, p = 0.0087). -reduction (3 months) and BSI-reduction (on ENZ treatment) were significant response biomarkers, and a negative CTC status was a predictive factor for ENZ efficacy in patients with mCRPC.

A randomised, double-blind, dose-finding, phase II multicentre study of ODX in the treatment of patients with castration-resistant prostate cancer and skeletal metastases

AIMS

This study aimed to assess the efficacy and safety of ODX, a novel, cytotoxic, bone-targeting drug candidate, in castration-resistant prostate cancer bone metastatic disease.

METHODS

Patients with progressive disease were randomised to ten cycles of ODX, intravenous infusion Q2W (3, 6, and 9 mg/kg, respectively). The primary objective was to assess the relative change from baseline in bone alkaline phosphatase (B-ALP) and serum-aminoterminal-propeptide of Type I procollagen (S-P1NP) at 12 weeks. The inclusion criteria selected were broad, and a double-blind design was used to ensure objective recruitment of patients for the assessment of efficacy. None of the patients received bone-protecting agents during the ODX treatment period.

RESULTS

Fifty-five 21,20 and 14) patients were randomised to ODX (3, 6 and 9 mg/kg), respectively. The lower number of patients in arm 3 was due to too low a recruitment rate towards the end of the study. The median treatment time were 14, 13 and 14 weeks, respectively. The decrease in B-ALP at 12 weeks in study arms 3, 6 and 9 mg/kg was seen in 6/15 (40%), 8/12 (67%) and 5/12 (42%) patients, respectively, whereas the corresponding numbers for P1NP were 8/15 (53%), 8/12 (67%), and 4/12 (33%), respectively. The median decrease in B-ALP and P1NP at 12 weeks for study arms 3, 6 and 9 mg/kg were 37%, 14% and 43%, respectively, and 51%, 40% and 64%, respectively. The decrease in serum C-terminal telopeptide at 12 weeks was seen in the vast majority of patients and in about one-third of patients in bone scan index. ODX was well tolerated, and no drug-related serious adverse events occurred. There were no significant differences between study arms regarding efficacy and safety.

CONCLUSIONS

ODX was well tolerated and demonstrated inhibitory effects on markers related to the vicious cycle in bone at all three doses. The reduction in metastatic burden, assessed with bone scan index, supports this finding. Studies with continued ODX treatment until disease progression are being planned (ClinicalTrials.gov Identifier: NCT02825628).

Clinical Significance of the Highest Regional Bone Scan Index in Patients with Metastatic Castration-Resistant Prostate Cancer

Purpose

This study evaluated the clinical utility of the highest bone scan index (BSI), among other BSIs, for each bone metastatic site in patients with bone metastatic castration-resistant prostate cancer (bmCRPC).

Methods

Thirty patients, diagnosed with bmCRPC by bone scintigraphy, were included. Total BSI, the number of hot spots, and regional BSI on each hot spot from bone scintigraphy at diagnosis with bmCRPC were evaluated by VSBONE BSI®. Highest regional BSI was defined as the highest value among regional BSIs on each hot spot in each patient. Related factors to overall survival and skeletal-related events (SREs) were evaluated using the Cox proportional-hazards model.

Results

The median follow-up time from diagnosis with bmCRPC was 29.0 months. During this time, 24 patients died, of which 22 patients died from prostate cancer. On univariate analysis, alkaline phosphatase (ALP) [Hazard ratio (HR): 5.96, 95% confidence interval (CI): 2.05-17.3] and highest regional BSI (HR: 2.01, 95% CI: 1.17-7.05) had significant correlation with overall survival. On multivariate analysis, ALP (HR: 4.79, 95% CI: 1.61-14.2) had significant correlation with overall survival. SREs were found in eight patients. Only the highest regional BSI (HR: 9.99, 95% CI: 2.46-40.6) significantly correlated with SREs on univariate analysis.

Conclusion

Highest regional BSI may provide important information regarding prognosis and SREs in patients with bmCRPC.

Factors influencing survival in metastatic castration resistant prostate cancer therapy

INTRODUCTION

The number of patients with metastatic castration resistant prostate cancer (mCRPC) is expecting to increase due to the long-life expectancy of those with advanced disease who are also more commonly diagnosed today because of stage migration. Several compounds are available for treating these patients.

AREAS COVERED

We reviewed currently available treatments for mCRPC, their mechanism of action and resistance and we explored possible predictors of treatment success useful to predict survival in mCRPC patients.

EXPERT OPINION

A combination of molecular, clinical, pathological, and imaging features is necessary to correctly estimate patients' risk of death. The combination of these biomarkers may allow clinicians to tailor treatments based on cancer history and patients' features. The search of predictive biomarkers remains an unmet medical need for most patients with mCRPC.

Comparison of 68Ga-PSMA PET/CT with fluoride PET/CT for detection of bone metastatic disease in prostate cancer

Background

¹⁸F-NaF positron emission tomography/computed tomography (fluoride PET/CT) is considered the most sensitive technique to detect bone metastasis in prostate cancer (PCa). ⁶⁸Ga-PSMA-11 (PSMA) PET/CT is increasingly used for staging of PCa. This study primarily aimed to compare the diagnostic performance of fluoride PET/CT and gallium-based PSMA PET/CT in identifying bone metastasis followed by a comparison of PSMA PET/CT with contrast-enhanced CT (CE-CT) in identifying soft tissue lesions as a secondary objective.

Methods

Twenty-eight PCa patients with high suspicion of disseminated disease following curative treatment were prospectively evaluated. PET/CT examinations using fluoride and PSMA were performed. All suspicious bone lesions were counted, and the tracer uptake was measured as standardized uptake values (SUV) for both tracers. In patients with multiple findings, ten bone lesions with highest SUV_max were selected from which identical lesions from both scans were considered for direct comparison of SUV_max. Soft tissue findings of local and lymph node lesions from CE-CT were compared with PSMA PET/CT.

Results

Both scans were negative for bone lesions in 7 patients (25%). Of 699 lesions consistent with skeletal metastasis in 21 patients on fluoride PET/CT, PSMA PET/CT identified 579 lesions (83%). In 69 identical bone lesions fluoride PET/CT showed significantly higher uptake (mean SUV_max: 73.1 ± 36.8) compared to PSMA PET/CT (34.5 ± 31.4; p < 0.001). Compared to CE-CT, PSMA PET/CT showed better diagnostic performance in locating local (96% vs 61%, p = 0.004) and lymph node (94% vs 46%, p < 0.001) metastasis.

Conclusion

In this prospective comparative study, PSMA PET/CT detected the majority of bone lesions that were positive on fluoride PET/CT. Further, this study indicates better diagnostic performance of PSMA PET/CT to locate soft tissue lesions compared to CE-CT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41824-022-00127-4.

Prognostic value of the bone scan index in patients with metastatic castration-resistant prostate cancer: a systematic review and meta-analysis

Background

Many studies have reported the prognostic significance of the bone scan index (BSI) for metastatic castration-resistant prostate cancer (mCRPC); however, these reports are controversial. This study investigated the BSI in mCRPC and its relationship with prognosis.

Methods

The PubMed, Cochrane, and Embase databases were searched systematically for relevant articles published before September 1, 2019. Hazard ratios (HRs) were used to investigate the prognostic value.

Results

This study finally identified 9 eligible studies. The results suggested that high baseline BSI predicted poor OS (HR = 1.331, 95% CI: 1.081–1.640) and that elevated ΔBSI also predicted poor OS (HR = 1.220, 95% CI: 1.015–1.467). The subgroup analysis stratified by ethnicity showed that the baseline BSI and ΔBSI predicted poor OS in the Asian population but not in the Caucasian population. We also performed a subgroup analysis based on the different cut-off values of baseline BSI. The subgroup of ≤1 showed a significant association with OS in mCRPC patients.

Conclusion

Our study demonstrated that high baseline BSI and elevated ΔBSI predicted poor OS in patients with mCRPC. Hence, the BSI can serve as a prognostic indicator for mCRPC patients and may therefore guide clinical treatment in the future.

Phase 3 Assessment of the Automated Bone Scan Index as a Prognostic Imaging Biomarker of Overall Survival in Men With Metastatic Castration-Resistant Prostate Cancer: A Secondary Analysis of a Randomized Clinical Trial

Importance

Prostate cancer commonly metastasizes to bone, and bone metastases are associated with pathologic fractures, pain, and reduced survival. Bone disease is routinely visualized using the technetium Tc 99m (99mTc) bone scan; however, the standard interpretation of bone scan data relies on subjective manual assessment of counting metastatic lesion numbers. There is an unmet need for an objective and fully quantitative assessment of bone scan data.

Objective

To clinically assess in a prospectively defined analysis plan of a clinical trial the automated Bone Scan Index (aBSI) as an independent prognostic determinant of overall survival (OS) in men with metastatic castration-resistant prostate cancer (mCRPC).

Design, Setting, and Participants

This investigation was a prospectively planned analysis of the aBSI in a phase 3 multicenter randomized, double-blind, placebo-controlled clinical trial of tasquinimod (10TASQ10). Men with bone metastatic chemotherapy-naïve CRPC were recruited at 241 sites in 37 countries between March 2011 and August 2015. The statistical analysis plan to clinically evaluate the aBSI was prospectively defined and locked before unmasking of the 10TASQ10 study. The analysis of aBSI was conducted between May 25, 2016, and June 3, 2017.

Main Outcomes and Measures

The associations of baseline aBSI with OS, radiographic progression-free survival (rPFS), time to symptomatic progression, and time to opiate use for cancer pain.

Results

Of the total 1245 men enrolled, 721 were evaluable for the aBSI. The mean (SD) age (available for 719 men) was 70.6 (8.0) years (age range, 47-90 years). The aBSI population was representative of the total study population based on baseline characteristics. The aBSI (median, 1.07; range, 0-32.60) was significantly associated with OS (hazard ratio [HR], 1.20; 95% CI, 1.14-1.26; P < .001). The median OS by aBSI quartile (lowest to highest) was 34.7, 27.3, 21.7, and 13.3 months, respectively. The discriminative ability of the aBSI (C index, 0.63) in prognosticating OS was significantly higher than that of the manual lesion counting (C index, 0.60) (P = .03). In a multivariable survival model, a higher aBSI remained independently associated with OS (HR, 1.06; 95% CI, 1.01-1.11; P = .03). A higher aBSI was also independently associated with time to symptomatic progression (HR, 1.18; 95% CI, 1.13-1.23; P < .001) and time to opiate use for cancer pain (HR, 1.21; 95% CI, 1.14-1.30; P < .001).

Conclusions and Relevance

To date, this investigation is the largest prospectively analyzed study to validate the aBSI as an independent prognostic imaging biomarker of survival in mCRPC. These data support the prognostic utility of the aBSI as an objective imaging biomarker in the design and eligibility of clinical trials of systemic therapies for patients with mCRPC.

Trial Registration

ClinicalTrials.gov Identifier: NCT01234311.

NaF PET/CT for response assessment of prostate cancer bone metastases treated with single fraction stereotactic ablative body radiotherapy

Introduction

In prostate cancer patients, imaging of bone metastases is enhanced through the use of sodium fluoride positron emission tomography (¹⁸F-NaF PET/CT). This imaging technique shows areas of enhanced osteoblastic activity and blood flow. In this work, ¹⁸F-NaF PET/CT was investigated for response assessment to single fraction stereotactic ablative body radiotherapy (SABR) to bone metastases in prostate cancer patients.

Methods

Patients with bone metastases in a prospective trial treated with single fraction SABR received a ¹⁸F-NaF PET/CT scan prior to and 6 months post-SABR. The SUV_max in the tumour was determined and the difference between before and after SABR determined. The change in uptake in the non-tumour bone was also measured as a function of the received SABR dose.

Results

Reduction in SUV_max was observed in 29 of 33 lesions 6 months after SABR (mean absolute decrease in SUV_max 17.7, 95% CI 25.8 to − 9.4, p = 0.0001). Of the three lesions with increased SUV_max post-SABR, two were from the same patient and located in the vertebral column. Both were determined to be local progression in addition to one fracture. The third lesion (in a rib) was shown to be controlled locally but suffered from a fracture at 24 months. Progression adjacent to the treated volume was observed in two patients. The non-tumour bone irradiated showed increased loss in uptake with increasing dose, with a median loss in uptake of 23.3% for bone receiving 24 Gy.

Conclusion

¹⁸F-NaF PET/CT for response assessment of bone metastases to single fraction SABR indicates high rates of reduction of osteoblastic activity in the tumour and non-tumour bone receiving high doses. The occurrence of marginal recurrence indicates use of larger clinical target volumes may be warranted in treatment of bone metastases.

Trial registration

POPSTAR, ‘Pilot Study of patients with Oligometastases from Prostate cancer treated with STereotactic Ablative Radiotherapy’, Universal Trial Number U1111-1140-7563, Registered 17th April 2013.

Electronic supplementary material

The online version of this article (10.1186/s13014-019-1359-0) contains supplementary material, which is available to authorized users.

Prognostic value of an automated bone scan index for men with metastatic castration-resistant prostate cancer treated with cabazitaxel

Background

A computer-assisted diagnostic system for analyzing bone scans (BONENAVI) calculates the automated bone scan index (aBSI). Here we evaluated the aBSI as a prognostic imaging biomarker for men with metastatic castration-resistant prostate cancer (mCRPC) treated with cabazitaxel.

Methods

We retrospectively analyzed 48 patients who received cabazitaxel for mCRPC and evaluated the ability of the aBSI to predict overall survival (OS). The Cox proportional hazards model was used to investigate the associations between baseline aBSI at cabazitaxel treatment and OS with the clinical variables as follows: age, number of cycles of docetaxel, serum prostate-specific antigen, hemoglobin (Hb), lactate dehydrogenase (LDH), and alkaline phosphatase. We determined the C-index to evaluate the discriminatory ability of our models when we included or excluded the aBSI from the analyses.

Results

The median OS after cabazitaxel treatment was 10.0 months, and patients with aBSI ≤1% achieved significantly longer OS compared with patients with aBSI ≥1%. Multivariate analysis showed that age, Hb, LDH, and aBSI were independent prognostic factors of OS. Adding aBSI to the base model increased the C-index from 0.78 to 0.80.

Conclusions

The aBSI may serve as a useful imaging biomarker for predicting OS among men with mCRPC treated with cabazitaxel. Prospective studies are required to establish the value of aBSI as prognostic imaging biomarker.

Prognostic value of bone scan index as an imaging biomarker in metastatic prostate cancer: a meta-analysis

Background

The prognostic value of the bone scan index (BSI) in metastatic prostate cancer (mPCa) remained controversial. Therefore, we performed a meta-analysis to determine the predictive value of BSI and survival in patients with mPCa.

Materials and Methods

A literature search was performed in PubMed, Embase, Web of Science and Cochrane library databases. Hazard ratios (HRs), concordance indices (C-indices) were extracted to estimate the relationship between BSI and survival in patients with mPCa. Subgroup analyses were conducted on different types of mPCa, ethnics, cut-off values and sample sizes.

Results

14 high quality studies involving 1295 patients with mPCa were included in this meta-analysis. The pooled results indicated that high basline BSI and elevated BSI change on treatment (ΔBSI) were significantly predictive of poor overall survial (HR = 1.29, P < 0.001; HR = 1.27, P < 0.001, respectively). Baseline BSI was also significantly related to cancer specific survival (HR = 1.65, P = 0.019) and prostate specific antigen recurrence survival (HR = 2.26, P < 0.001). Subgroup analysis supported main results. Moreover, BSI could increase the C-indices of predictive models.

Conclusions

Baseline BSI and ΔBSI may be beneficial to mPCa prognosis in clinical monitor and treatment. Further high quality studies with larger sample size are required in the future.