Prediction of survival benefit using an automated bone scan index in patients with castration-resistant prostate cancer

Circulating and Imaging Biomarkers of Radium-223 Response in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Radium-223 improves overall survival (OS) and reduces skeletal events in patients with bone metastatic castration-resistant prostate cancer (CRPC), but relevant biomarkers are lacking. We evaluated automated bone scan index (aBSI) and circulating tumor cell (CTC) analyses as potential biomarkers of prognosis and activity.

PATIENTS AND METHODS

Patients with bone metastatic CRPC were enrolled on a prospective single-arm study of standard radium-223. 99mTc-MDP bone scan images at baseline, 2 months, and 6 months were quantitated using aBSI. CTCs at baseline, 1 month, and 2 months were enumerated and assessed for RNA expression of prostate cancer-specific genes using microfluidic enrichment followed by droplet digital polymerase chain reaction.

RESULTS

The median OS was 21.3 months in 22 patients. Lower baseline aBSI and minimal change in aBSI (<+0.7) from baseline to 2 months were each associated with better OS (P = .00341 and P = .0139, respectively). The higher baseline CTC count of ≥5 CTC/7.5 mL was associated with worse OS (median, 10.1 v 32.9 months; P = .00568). CTCs declined at 2 months in four of 15 patients with detectable baseline CTCs. Among individual genes in CTCs, baseline expression of the splice variant AR-V7 was significantly associated with worse OS (hazard ratio, 5.20 [95% CI, 1.657 to 16.31]; P = .00195). Baseline detectable AR-V7, higher aBSI, and CTC count ≥5 CTC/7.5 mL continued to have a significant independent negative impact on OS after controlling for prostate-specific antigen or alkaline phosphatase.

CONCLUSION

Quantitative bone scan assessment with aBSI and CTC analyses are prognostic markers in patients treated with radium-223. AR-V7 expression in CTCs is a particularly promising prognostic biomarker and warrants validation in larger cohorts.

Quantitative assessment of PSMA PET response to therapy in castration-sensitive prostate cancer using an automated imaging platform for disease identification and measurement

RATIONALE

Prostate cancer treatment response may be automatically quantified using a molecular imaging analysis platform targeting prostate-specific membrane antigen (PSMA).

METHODS

A retrospective analysis of patients with castration-sensitive prostate cancer who underwent PSMA-targeted molecular imaging prior to and 3 months or more after treatment was conducted. Disease burden was analyzed with aPROMISE, an artificial intelligence imaging platform that automatically quantifies PSMA-positive lesions. The calculated PSMA scores for prostate/bed, nodal, and osseous disease sites were compared with prostate-specific antigen (PSA) values.

RESULTS

Of 30 eligible patients, the median decline in prostate/bed, nodal, and osseous disease PSMA scores were 100% (range 52-100%), 100% (range - 87-100%), and 100% (range - 21-100%), respectively. PSMA score decline was significantly associated with PSA decline.

CONCLUSION

Changes in aPROMISE PSMA scores are associated with changes in PSA and may quantify treatment response.

Novel quantitative software for automatically excluding red bone marrow on whole-body magnetic resonance imaging in patients with metastatic prostate cancer: A pilot study

OBJECTIVES

To establish a novel quantitative method that automatically excludes the red bone marrow and accurately quantifies the tumor volume on whole-body magnetic resonance imaging using updated imaging software. To also evaluate the association between the quantified tumor volume and the prognosis of patients with metastatic prostate cancer.

METHODS

This prospective analysis included patients diagnosed with metastatic hormone-sensitive or metastatic castration-resistant prostate cancer between 2017 and 2022. We developed an imaging software (Attractive BD_Score) that analyzed whole-body diffusion-weighted and in-phase and opposed-phase T1-weighted images to automatically exclude the red bone marrow. The quantified tumor volume was compared with that quantified by traditional whole-body diffusion-weighted imaging without red bone marrow exclusion. Prostate-specific antigen progression-free survival, time-to-pain progression, and overall survival were evaluated to assess the prognostic value of the quantified tumor volume.

RESULTS

The quantified tumor volume was significantly smaller than that quantified by the traditional method in metastatic hormone-sensitive (median: 81.0 ml vs. 149.4 ml) and metastatic castration-resistant (median: 29.4 ml vs. 63.5 ml) prostate cancer. A highly quantified tumor volume was associated with prostate-specific antigen progression-free survival (p = 0.030), time-to-pain progression (p = 0.003), and overall survival (p = 0.005) in patients with metastatic hormone-sensitive prostate cancer and with poor prostate-specific antigen progression-free survival (p = 0.001) and time-to-pain progression (p = 0.005) in patients with metastatic castration-resistant prostate cancer.

CONCLUSIONS

Our imaging method could accurately quantify the tumor volume in patients with metastatic prostate cancer. The quantified tumor volume can be clinically applied as a new prognostic biomarker for metastatic prostate cancer.

Quantitative assessment of 99mTc-methylene diphosphonate bone SPECT/CT for assessing bone metastatic burden and its prognostic value in patients with castration-resistant prostate cancers: initial results in a single-center retrospective study

PURPOSE

To evaluate the prognostic value of the quantitative assessment of ^99mTc-methylene diphosphonate (^99mTc-MDP) bone SPECT/CT in castration-resistant prostate cancer (CRPC) patients with bone metastases.

METHODS

A total of 103 patients who underwent ^99mTc-MDP bone SPECT/CT imaging from the neck to the proximal femur were included. First, in 65 patients without bone metastases, the normal range of standardized uptake value (SUV) of non-pathological bone was evaluated to determine an SUV threshold to reliably exclude most normal osseous activity. Then, in 38 CRPC patients with bone metastases, lesion uptake volume (LUV), which is the extracted volume of bone metastases exhibiting high accumulation above the SUV threshold, was calculated. The relation between LUV and prostate-related mortality was statistically evaluated.

RESULTS

Based on the SUV measurements of non-pathological bones, the optimal SUV threshold, which defines abnormal bone SPECT uptake, was determined to be 8. Median LUV was 39 mL (interquartile range 4.0-104.3 mL) in the CRPC subjects with bone metastases. Kaplan-Meier survival analysis showed a significant relation between prostate cancer-specific survival and LUV (cut-off value, 19.95 mL; P = 0.001). Multivariate analysis revealed LUV as an independent prognostic factor for the survival (P = 0.008, hazard ratio 23.424). Global chi-square test showed that LUV had significant incremental prognostic value in addition to prostate-specific antigen and the interval from progression to CRPC until bone SPECT/CT (P = 0.022).

CONCLUSION

Quantitative assessment of ^99mTc-MDP bone SPECT images can provide valuable prognostic information in CRPC patients with bone metastases.

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).

Bone Health Management in the Continuum of Prostate Cancer Disease

Prostate cancer (PCa) is the second-leading cause of cancer-related deaths in men. PCa cells require androgen receptor (AR) signaling for their growth and survival. Androgen deprivation therapy (ADT) is the preferred treatment for patients with locally advanced and metastatic PCa disease. Despite their initial response to androgen blockade, most patients eventually will develop metastatic castration-resistant prostate cancer (mCRPC). Bone metastases are common in men with mCRPC, occurring in 30% of patients within 2 years of castration resistance and in >90% of patients over the course of the disease. Patients with mCRPC-induced bone metastasis develop lesions throughout their skeleton; the 5-year survival rate for these patients is 47%. Bone-metastasis-induced early changes in the bone that proceed the osteoblastic response in the bone matrix are monitored and detected via modern magnetic resonance and PET/CT imaging technologies. Various treatment options, such as targeting osteolytic metastasis with bisphosphonates, prednisone, dexamethasone, denosumab, immunotherapy, external beam radiation therapy, radiopharmaceuticals, surgery, and pain medications are employed to treat prostate-cancer-induced bone metastasis and manage bone health. However, these diagnostics and treatment options are not very accurate nor efficient enough to treat bone metastases and manage bone health. In this review, we present the pathogenesis of PCa-induced bone metastasis, its deleterious impacts on vital organs, the impact of metastatic PCa on bone health, treatment interventions for bone metastasis and management of bone- and skeletal-related events, and possible current and future therapeutic options for bone management in the continuum of prostate cancer disease.

Appropriate Patient Status for Ra-223 Treatment in the Treatment Sequence for Castration-resistant Prostate Cancer

BACKGROUND/AIM

Radium (Ra)-223 is widely used for treating castration-resistant prostate cancer (CRPC) with bone metastasis based on evidence of increased survival and decreased skeletal-related events. However, the timing of Ra-223 use in the treatment sequence of CRPC remains controversial. Therefore, this study aimed to explore the appropriate patient status for Ra-223 use in the CRPC treatment sequence by examining patients treated with Ra-223 from the time of CRPC diagnosis until death.

PATIENTS AND METHODS

The medical records of 67 CRPC patients with bone metastasis who were treated with Ra-223 at two institutes were retrospectively analysed. The impact of 13 factors from the time of CRPC diagnosis until death was analysed using univariate and multivariate Cox hazard ratio models to evaluate the appropriate patient status for Ra-223 treatment.

RESULTS

The median survival time following CRPC diagnosis for all the patient groups was 3.82 years. Univariate analysis identified a higher-than-normal alkaline phosphatase (ALP) level, bone scan indexes ≥2, and prostate-specific antigen (PSA) doubling time <3 months before Ra-223 treatment as predominant adverse prognostic factors. Ra-223 therapy discontinuation was not a significant factor. The survival of CRPC patients with these factors was significantly worse than that of patients without these factors. In the multivariate analysis, a higher-than-normal ALP level at the start of treatment was identified as a poor prognostic factor for mortality.

CONCLUSION

The appropriate patient status for Ra-223 use includes low bone metastasis burden and well-controlled PSA levels.

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.

Novel diagnostic model for bone metastases in renal cell carcinoma patients based on bone scintigraphy analyzed by computer-aided diagnosis software and bone turnover markers

Background

Computer-assisted diagnosis (CAD) systems for bone scans have been introduced as clinical quality assurance tools, but few studies have reported on its utility for renal cell carcinoma (RCC) patients. The aim of this study was to assess the diagnostic validity of the CAD system for bone scans and to construct a novel diagnostic system for bone metastases in RCC patients.

Methods

We evaluated bone scan images of 300 RCC patients. Artificial neural network (ANN) values, which represent the probability of abnormality, were calculated by BONENAVI, the CAD software for bone scans. By analyzing ANN values, we assessed the diagnostic validity of BONENAVI. Next, we selected 108 patients who underwent measurements of bone turnover markers and assessed the combined diagnostic validity of BONENAVI and bone turnover markers.

Results

Forty-three out of 300 RCC patients had bone metastases. The AUC of ANN values was 0.764 and the optimum sensitivity and specificity were 83.7 and 62.7%. By logistic analysis of 108 cases, we found that ICTP, a bone resorption marker, could be a diagnostic marker. The AUC of ICTP was 0.776 and the optimum sensitivity and specificity were 57.1 and 86.8%. Subsequently, we developed a novel diagnostic model based on ANN values and ICTP. Using this model, the AUC was 0.849 and the optimum sensitivity and specificity were 76.2 and 80.7%.

Conclusion

By combining the high sensitivity provided by BONENAVI and the high specificity provided by ICTP, we constructed a novel, high-accuracy diagnostic model for bone metastases in RCC patients.

Study of the Usefulness of Bone Scan Index Calculated From 99m-Technetium- Hydroxymethylene Diphosphonate (99mTc-HMDP) Bone Scintigraphy for Bone Metastases from Prostate Cancer Using Deep Learning Algorithms

BACKGROUND

BSI calculated from bone scintigraphy using ^99mtechnetium-methylene diphosphonate (^99mTc-MDP) is used as a quantitative indicator of metastatic bone involvement in bone metastasis diagnosis, therapeutic effect assessment, and prognosis prediction. However, the BONE NAVI, which calculates BSI, only supports bone scintigraphy using ^99mTc-MDP.

AIMS

We developed a method in collaboration with the Tokyo University of Agriculture and Technology to calculate bone scan index (BSI) employing deep learning algorithms with bone scintigraphy images using ^99mtechnetium-hydroxymethylene diphosphonate (^99mTc-HMDP). We used a convolutional neural network (CNN), enabling the simultaneous processing of anterior and posterior bone scintigraphy images named CNNapis.

OBJECTIVES

The purpose of this study is to investigate the usefulness of the BSI calculated by CNNapis as bone imaging and bone metabolic biomarkers in patients with bone metastases from prostate cancer.

METHODS

At our hospital, 121 bone scintigraphy scans using ^99mTc-HMDP were performed and analyzed to examine bone metastases from prostate cancer, revealing the abnormal accumulation of radioisotope (RI) at bone metastasis sites. Blood tests for serum prostate-specific antigen (PSA) and alkaline phosphatase (ALP) were performed concurrently. BSI values calculated by CNNapis were used to quantify the metastatic bone tumor involvement. Correlations between BSI and PSA and between BSI and ALP were calculated. Subjects were divided into four groups by BSI values (Group 1, 0 to <1; Group 2, 1 to <3; Group 3, 3 to <10; Group 4, >10), and the PSA and ALP values in each group were statistically compared.

RESULTS

Patients diagnosed with bone metastases after bone scintigraphy were also diagnosed with bone metastases using CNNapis. BSI corresponding to the range of abnormal RI accumulation was calculated. PSA and BSI (r = 0.2791) and ALP and BSI (r = 0.6814) correlated positively. Significant intergroup differences in PSA between Groups 1 and 2, Groups 1 and 4, Groups 2 and 3, and Groups 3 and 4 and in ALP between Groups 1 and 4, Groups 2 and 4, and Groups 3 and 4 were found.

CONCLUSION

BSI calculated using CNNapis correlated with ALP and PSA values and is useful as bone imaging and bone metabolic biomarkers, indicative of the activity and spread of bone metastases from prostate cancer.

A novel tool for improving the interpretation of isotope bone scans in metastatic prostate cancer

OBJECTIVES

The isotope bone scan (IBS) is the gold-standard imaging modality for detecting skeletal metastases as part of prostate cancer staging. However, its clinical utility for assessing skeletal metastatic burden is limited due to the need for subjective interpretation. We designed and tested a novel custom software tool, the Metastatic Bone Scan Tool (MetsBST), aimed at improving interpretation of IBSs, and compared its performance with that of an established software programme.

METHODS

We used IBS images from 62 patients diagnosed with prostate cancer and suspected bone metastases to design and implement MetsBST in MATLAB by defining thresholds used to identify the texture and size of metastatic bone lesions. The results of MetsBST were compared with those of the commercially available automated Bone Scan Index (aBSI) with regression analysis.

RESULTS

There was strong agreement between the MetsBST and aBSI results (R² = 0.9189). In a subregional analysis, MetsBST quantified the extent of metastatic disease in multiple bone sites in patients receiving multimodality therapy (radium-223 and external beam radiotherapy) to illustrate the differences in bone metastatic response to different treatments.

CONCLUSION

The results of MetsBST and the commercial software aBSI were highly consistent. MetsBST introduces novel clinical utility by its ability to differentiate between the responses of different bone metastases to multimodality therapies.

ADVANCES IN KNOWLEDGE

MetsBST reduces the variability in assessment of tumour burden caused by subjective interpretation. Therefore, it is a useful aid to physicians reporting nuclear medicine scans, and may improve decision-making in the treatment of metastatic prostate cancer.

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.

Patterns of response and progression in bone and soft tissue during and after treatment with radium-223 for metastatic castrate-resistant prostate cancer

BACKGROUND

Radium-223 improves survival and time to first symptomatic skeletal event in symptomatic bone predominant metastatic castrate-resistant prostate cancer (mCRPC). The imaging response to radium-223 has not been well characterized.

METHODS

To describe patterns of response and progression with radium-223, we performed a retrospective review of all mCPRC patients who received radium-223 at Duke from 1 June 2013 to 1 June 2015. Radionuclide bone scans obtained at baseline, during, and after treatment were reviewed by two radiologists. The automated bone scan index (aBSI) was generated at each time point using EXINI bone^BSI version 2.4. Computed tomography (CT) and magnetic resonance imaging (MRI) clinical radiology reports were reviewed to evaluate for soft tissue, visceral, epidural, and bone progression. Clinical data were abstracted from the electronic health record.

RESULTS

We identified 61 men who received at least one dose of radium-223 at Duke during the study period (median, 5 doses; range, 1-6). Among men with imaging during treatment, 2 of 14 (14.3%) had resolution of greater than or equal to 1 lesion on bone scan, 4 of 14 (28.6%) had zero new bone lesions, 10 of 14 (71.4%) had greater than or equal to 1 new bone lesion, 14 of 26 (53.9%) progressed on CT. After radium-223, 6 of 39 (15.4%) had resolution of 1 to 4 bone lesions, 15 of 39 (38.5%) demonstrated zero new bone lesions, 24 of 39 (61.5%) progressed on bone scan, 15 of 37 (40.5%) progressed on CT, and 10 of 34 (29.4%) progressed on both bone scan and CT. No men with zero new bone lesions after radium-223 ultimately progressed in bone alone and only 3 of 15 eventually demonstrated any progression in the bone. aBSI decreased significantly from baseline to after radium-223 among men with zero new bone lesions (median change in aBSI -0.23 [IQR, -1.5, 0.02]) and increased significantly for men with greater than or equal to 1 new postradium bone lesions (median change in aBSI 1.41 [IQR, -0.05, 3.63] [P = 0.018]).

CONCLUSIONS

Bone and soft tissue progression during and following radium-223 is common in heavily pretreated men with mCRPC. However, stable disease and responses were observed in a subset of patients and may be associated with durable treatment response in the bone. Prospective studies are needed to further investigate the change in aBSI as a biomarker of bone scan response/stabilization and progression following treatment with radium-223.

Bone scan index can be a useful biomarker of survival outcomes in patients with metastatic castration-resistant prostate cancer treated with radium-223

BACKGROUND

Bone metastasis of prostate cancer is associated with pain and reduced overall survival (OS). Radium-223, which is expected to reduce bone pain and prolong OS, was recently approved in Japan.

AIM

The aim of this study was to investigate the usefulness of the bone scan index by comparing the outcomes and factors according to response in Japanese patients treated with radium-223.

METHODS AND RESULTS

Twenty patients receiving radium-223 were divided into two groups according to whether they did or did not achieve a bone scan index decrease of at least one point (beneficial and non-beneficial groups, respectively). The clinical characteristics at baseline and after three and six treatment cycles were compared using χ² tests and Student's t-tests or Mann-Whitney U tests, and survival was estimated and compared using the Kaplan-Meier method and log-rank test, respectively. Fourteen (70%) and six patients (30%) were categorized into the beneficial and non-beneficial groups, respectively. Patients in the former group were significantly more likely to have a higher Eastern Cooperative Oncology Group performance status score and receive a greater number of radium-223 injections (P < 0.05). Furthermore, patients in the beneficial group had a significantly longer OS (P < 0.05). Regarding safety, one and three patients in the beneficial and non-beneficial groups, respectively, prematurely discontinued radium-223 because of an increased prostate-specific antigen level, decreased hemoglobin level, or femoral fracture.

CONCLUSION

Radium-223 appears generally safe in this population. Patients with good bone scan index response have better performance status, receive more injections of radium-223, and achieve OS prolongation. Bone scan index is a useful biomarker of survival outcomes and can be a valuable assessment tool in patients with metastatic castration-resistant prostate cancer who are treated with radium-223.

A novel biomarker, active whole skeletal total lesion glycolysis (WS-TLG), as a quantitative method to measure bone metastatic activity in breast cancer patients

Objective

There is no good response evaluation method for skeletal metastasis. We aimed to develop a novel quantitative method to evaluate the response of skeletal metastasis, especially lytic lesions, for treatment.

Methods

A method to measure active bone metastatic burden quantitatively using F-18 fluorodeoxyglucose positron emission tomography with computed tomography (FDG–PET/CT) in breast cancer patients, whole skeletal total lesion glycolysis (WS-TLG), a summation of each skeletal lesion’s TLG, was developed. To identify active bone lesions, a tentative cutoff value was decided using FDG–PET/CT in 85 breast cancer patients without skeletal metastasis and 35 with skeletal metastasis by changing the cutoff value. Then, the WS-TLG method was evaluated by comparing to PET Response Criteria in Solid Tumor (PERCIST) or European Organization for Research and Treatment of Cancer (EORTC) criteria for only bone in 15 breast cancer patients with skeletal metastasis who were treated.

Results

A cutoff value of the standardized uptake value (SUV) = 4.0 gave 91% (77/85) specificity and 97% (34/35) sensitivity. We decided on SUV = 4.0 as a tentative cutoff value. Skeletal metastases of lytic and mixed types showed higher WS-TLG values than those of blastic or intertrabecular types, although statistical significance was not tested. All 15 patients showed agreement with PERCIST or EORTC in the therapeutic bone response.

Conclusion

This quantitative WS-TLG method appears to be a good biomarker to evaluate skeletal metastasis in breast cancer patients, especially lytic or mixed types. Further clinical studies are warranted to assess the clinical values of this new WS-TLG method.

Bone scan index as metastatic bone disease quantifier and predictor of radium-223-dichloride biochemical response

OBJECTIVES

This work aims to assess whether the biochemical response of radium-223-dichloride treatment can be predicted based on the pretherapy bone scan, and consequently if bone scan index (BSI) and maximum lesion intensity have a place as alternatives or as complements to extent of bone disease (EOBD) scoring in predicting biochemical response to treatment. Many cases of advanced prostate cancer have evidence of bone metastasis. Accurate EOBD quantification could help predict the response to radium-223-dichloride therapy. Current EOBD score is simple to use but does not consider size, intensity or localisation of lesion BSI might be more suitable for stratification of bone metastases.

PATIENTS AND METHODS

Bone scans (n=20) preceding radium-223-dichloride treatment for prostate cancer were assessed retrospectively using automated BSI software (EXINI) and by assessing maximum counts per lesion. Results were then compared to total alkaline phosphatase (ALP) as a measure of biochemical response to therapy using linear regressions and to their EOBD scores using box plot analysis.

RESULTS

Moderate correlation was found between ALP response and maximum lesion intensity (R=0.41) and BSI (R=0.46). Strong correlation (R=0.71) was found between baseline ALP and BSI and between lesion number and BSI (R=0.60). Visual assessment of EOBD score was found to correlate well with baseline ALP and maximum ALP response.

CONCLUSION

BSI is a useful asset in stratification of patients with metastatic bone disease. It may also have a place in prediction of biochemical response.

Prospective comparative study of 18F-sodium fluoride PET/CT and planar bone scintigraphy for treatment response assessment of bone metastases in patients with prostate cancer

AIM

To compare ¹⁸F-sodium fluoride positron emission tomography/computed tomography (NaF PET/CT) and ^99mTc-labelled diphosphonate bone scan (BS) for the monitoring of bone metastases in patients with prostate cancer undergoing anti-cancer treatment.

MATERIAL AND METHODS

Data from 64 patients with prostate cancer were included. The patients received androgen-deprivation therapy (ADT), next-generation hormonal therapy (NGH) or chemotherapy. The patients had a baseline scan and 1-3 subsequent scans during six months of treatment. Images were evaluated by experienced nuclear medicine physicians and classified for progressive disease (PD) or non-PD according to the Prostate Cancer Working Group 2 (PCWG-2) criteria. The patients were also classified as having PD/non-PD according to the clinical and prostate-specific antigen (PSA) responses.

RESULTS

There was no difference between NaF PET/CT and BS in the detection of PD and non-PD during treatment (McNemar's test, p = .18). The agreement between BS and NaF PET/CT for PD/non-PD was moderate (Cohen's kappa 0.53, 95% confidence interval 0.26-0.79). Crude agreement between BS and NaF PET/CT for the assessment of PD/non-PD was 86% (89% for ADT, n = 28; 88% for NGH, n = 16, and 80% for chemotherapy, n = 20). In most discordant cases, BS found PD when NaF PET/CT did not, or BS detected PD on an earlier scan than NaF PET/CT. Biochemical progression (27%) occurred more frequently than progression on functional imaging (BS, 22% and NaF PET/CT, 14%). Clinical progression was rare (11%), and almost exclusively seen in patients receiving chemotherapy.

CONCLUSION

There was no difference between NaF PET/CT and BS in the detection of PD and non-PD; however, BS seemingly detects PD by the PCWG-2 criteria earlier than NaF-PET, which might be explained by the fact that NaF-PET is more sensitive at the baseline scan.

Assessment of Skeletal Tumor Load in Metastasized Castration-Resistant Prostate Cancer Patients: A Review of Available Methods and an Overview on Future Perspectives

Metastasized castration-resistant prostate cancer (mCRPC), is the most advanced form of prostate neoplasia, where massive spread to the skeletal tissue is frequent. Patients with this condition are benefiting from an increasing number of treatment options. However, assessing tumor response in patients with multiple localizations might be challenging. For this reason, many computational approaches have been developed in the last decades to quantify the skeletal tumor burden and treatment response. In this review, we analyzed the progressive development and diffusion of such approaches. A computerized literature search of the PubMed/Medline was conducted, including articles between January 2008 and March 2018. The search was expanded by manually reviewing the reference list of the chosen articles. Thirty-five studies were identified. The number of eligible studies greatly increased over time. Studies could be categorized in the following categories: automated analysis of 2D scans, SUV-based thresholding, hybrid CT- and SUV-based thresholding, and MRI-based thresholding. All methods are discussed in detail. Automated analysis of bone tumor burden in mCRPC is a growing field of research; when choosing the appropriate method of analysis, it is important to consider the possible advantages as well as the limitations thoroughly.

Fluorine-18-fluorocholine PET/CT parameters predictive for hematological toxicity to radium-223 therapy in castrate-resistant prostate cancer patients with bone metastases: a pilot study

PURPOSE

This study aims to predict hematological toxicity induced by Ra therapy. We investigated the value of metabolically active bone tumor volume (MBTV) and total bone lesion activity (TLA) calculated on pretreatment fluorine-18-fluorocholine (F-FCH) PET/CT in castrate-resistant prostate cancer (CRPC) patients with bone metastases treated with Ra radionuclide therapy.

PATIENTS AND METHODS

F-FCH PET/CT imaging was performed in 15 patients with CRPC before treatment with Ra. Bone metastatic disease was quantified on the basis of the maximum standardized uptake value (SUV), total lesion activity (TLA=MBTV×SUVmean), or MBTV/height (MBTV/H) and TLA/H. F-FCH PET/CT bone tumor burden and activity were analyzed to identify which parameters could predict hematological toxicity [on hemoglobin (Hb), platelets (PLTs), and lymphocytes] while on Ra therapy. Pearson's correlation was used to identify the correlations between age, prostate-specific antigen, and F-FCH PET parameters.

RESULTS

MBTV ranged from 75 to 1259 cm (median: 392 cm). TLA ranged from 342 to 7198 cm (median: 1853 cm). Patients benefited from two to six cycles of Ra (n=56 cycles in total). At the end of Ra therapy, five of the 15 (33%) patients presented grade 2/3 toxicity on Hb and lymphocytes, whereas three of the 15 (20%) patients presented grade 2/3 PLT toxicity.Age was correlated negatively with both MBTV (r=-0.612, P=0.015) and TLA (r=-0.596, P=0.018). TLA, TLA/H, and MBTV/H predicted hematological toxicity on Hb, whereas TLA/H and MBTV/H predicted toxicity on PLTs at the end of Ra cycles. Receiver operating characteristic curve analysis allowed to define the cutoffs for MBTV (915 cm) and TLA (4198 cm) predictive for PLT toxicity, with an accuracy of 0.92 and 0.99.

CONCLUSION

Tumor bone burden calculation is feasible with F-FCH PET/CT with freely available open-source software. In this pilot study, baseline F-FCH PET/CT markers (TLA, MBTV) have shown abilities to predict Hb and PLT toxicity after Ra therapy and could be explored for patient selection and treatment optimization.

A prospective study to evaluate the intra-individual reproducibility of bone scans for quantitative assessment in patients with metastatic prostate cancer

BACKGROUND

The Bone Scan Index (BSI) is used to quantitatively assess the total tumour burden in bone scans of patients with metastatic prostate cancer. The clinical utility of BSI has recently been validated as a prognostic imaging biomarker. However, the clinical utility of the on-treatment change in BSI is dependent on the reproducibility of bone scans. The objective of this prospective study is to evaluate the intra-patient reproducibility of two bone scan procedures performed at a one-week interval.

METHODS

We prospectively studied prostate cancer patients who were referred for bone scintigraphy at our centres according to clinical routine. All patients underwent two whole-body bone scans: one for clinical routine purposes and a second one as a repeated scan after approximately one week. BSI values were obtained for each bone scintigraph using EXINI bone^BSI software.

RESULTS

A total of 20 patients were enrolled. There was no statistical difference between the BSI values of the first (median = 0.66, range 0-40.77) and second (median = 0.63, range 0-22.98) bone scans (p = 0.41). The median difference in BSI between the clinical routine and repeated scans was - 0.005 (range - 17.79 to 0). The 95% confidence interval for the median value was - 0.1 to 0. A separate analysis was performed for patients with BSI ≤ 10 (n = 17). Differences in BSI were smaller for patients with BSI ≤ 10 compared to the whole cohort (median - 0.1, range - 2.2-0, 95% confidence interval - 0.1 to 0).

CONCLUSIONS

The automated BSI demonstrated high intra-individual reproducibility for BSI ≤ 10 in the two repeated bone scans of patients with prostate cancer. The study supports the use of BSI as a quantitative parameter to evaluate the change in total tumour burden in bone scans.

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.

Evaluation of changes in Bone Scan Index at different acquisition time-points in bone scintigraphy

Bone Scan Index (BSI) is a validated imaging biomarker to objectively assess tumour burden in bone in patients with prostate cancer, and can be used to monitor treatment response. It is not known if BSI is significantly altered when images are acquired at a time difference of 1 h. The aim of this study was to investigate if automatic calculation of BSI is affected when images are acquired 1 hour apart, after approximately 3 and 4 h. We prospectively studied patients with prostate cancer who were referred for bone scintigraphy according to clinical routine. The patients performed a whole-body bone scan at approximately 3 h after injection of radiolabelled bisphosphonate and a second 1 h after the first. BSI values for each bone scintigraphy were obtained using EXINI boneBSI software. A total of 25 patients were included. Median BSI for the first acquisition was 0·05 (range 0-11·93) and for the second acquisition 0·21 (range 0-13·06). There was a statistically significant increase in BSI at the second image acquisition compared to the first (P<0·001). In seven of 25 patients (28%) and in seven of 13 patients with BSI > 0 (54%), a clinically significant increase (>0·3) was observed. The time between injection and scanning should be fixed when changes in BSI are important, for example when monitoring therapeutic efficacy.

The Economic Burden of Metastatic Castration Resistant Prostate Cancer and Skeletal Related Events in Japanese University Hospitals

Objective:

Although androgen deprivation therapy (ADT) has improved the survival and quality of life of patients with prostate cancer, resistance to treatment inevitably results in transition to a castration resistant state (CRPC) and, in advanced cases, bone metastasis, leading to skeletal related events (SRE). In order to understand the current burden on patients in Japan, there is a need to estimate the healthcare costs of CRPC treatment in current clinical practice.

Methods:

This retrospective observational cohort study utilized claims data from 13 national university hospitals through the Platform for Clinical Information Statistical Analysis database. Extracted data included the use of diagnostic tests, the frequency and cost of hospitalizations and outpatient visits, and medication costs, using values from the Healthcare Fee System and the National Health Insurance Drug Price List relative to each observed year.

Results:

Data were collected from 4001 patients with CRPC, 97% of whom had undergone ADT. Between 2005 and 2016, the mean annualized direct medical cost per patient was ¥739,147 (US$7060), of which 91% was related to medication, 4.8% to laboratory and imaging, 4.1% to radiotherapy, and 0.1% to surgery. A total of 771 (19%) of the 4001 CRPC patients experienced an SRE. Resource utilization was significantly higher (p<0.0001) in patients with SRE than in those without, with mean annualized medication costs per patient of ¥1,074,885 and ¥659,006, respectively, and ¥108,807 and ¥71,392, respectively, for laboratory and imaging. The occurrence of even one SRE led to a significant increase in costs and the use of analgesics, compared to the prior period.

Conclusions:

A diagnosis of CRPC is associated with considerable healthcare resource utilization and increased economic burden on patients, which are significantly higher in those with SREs. Treatments that can prevent or delay SREs may help ease this burden, thereby providing cost savings across Japanese healthcare systems.

Evaluation of bone metastatic burden by bone SPECT/CT in metastatic prostate cancer patients: defining threshold value for total bone uptake and assessment in radium-223 treated patients

Objectives

To establish a new three-dimensional quantitative evaluation method for bone metastasis, we applied bone single photon emission tomography with computed tomography (SPECT/CT). The total bone uptake (TBU), which measures active bone metastatic burden, was calculated as the sum of [mean uptake obtained as standardized uptake value (SUV) above a cut-off level] × (the volume of the lesion) in the trunk using bone SPECT/CT. We studied the threshold value and utility of TBU in prostate cancer patients treated with radium-223 (Ra-223) therapy.

Methods

To establish the threshold value of TBU, we compared bone metastatic and non-metastatic regions in 61 prostate cancer patients with bone metastasis and 69 without. Five fixed sites in each patient were selected as evaluation points and divided into bone metastatic and non-metastatic sites. Sensitivity and specificity analysis was applied to establish the threshold level. Using the obtained threshold value, we then calculated the TBU in nine prostate cancer patients who received Ra-223 therapy, and compared the results with the bone scan index (BSI) by BONENAVI^® and visual evaluation of bone scintigraphy.

Results

Uptake was significantly lower in non-metastatic sites in patients with bone metastasis than in patients without metastasis. Sensitivity and specificity analysis revealed SUV = 7.0 as the threshold level. There was a discrepancy between TBU and BSI change in two of the nine patients, in whom TBU change correlated with visual judgement, but BSI change did not. In two patients, BSI was nearly 0 throughout the course, but the TBU was positive and changed, although the change was not large. These results suggest that TBU may be more accurate and sensitive than BSI for quantitative evaluation of active bone metastatic burden.

Conclusion

We established a threshold value (SUV > 7.0) for three-dimensional TBU for evaluating active bone metastatic burden in prostate cancer patients using bone SPECT/CT. Despite the small number of patients, we expect the change in TBU could be more accurate and sensitive than the change in BSI among patients who received Ra-223.

Automated Bone Scan Index as Predictors of Survival in Prostate Cancer

Prostate cancer (PCa) is the second most diagnosed cancer in men. Early diagnosis and right management of PCa is critical to reducing deaths; the life expectancy is the main factors to be considered in the management of PCa. Among patients who die from PCa, the incidence of skeletal involvement appears to be >85%. Bone scan (BS) is the most common method for monitoring bone metastases in patients with PCa. The extent of bone metastasis was also associated with patient survival until now there is no clinically useful technique for measuring bone tumors and includes this information in the risk assessment. An alternative approach is to calculate a BS index (BSI) and it has shown clinical significance as a prognostic imaging biomarker. Some computer-assisted diagnosis (CAD) systems have been developed to measure BSI and are now available. The aim of this study was to investigate automated BSI (aBSI) measurements as predictors' survival in PCa. Retrospectively cohort studied fifty patients with PCa who had undergone BS between January 2010 and December 2011 at our institution. All data collected was updated up to August 2016. CAD system analyzing BS images to automatically compute BSI measurements. Patients were stratified into three BSI categories BSI value 0, BSI value ≤1 and BSI value >1. Kaplan-Meier estimates of the survival function and the log-rank test were used to indicate a significant difference between groups stratified in accordance with the BSI values. A total of 35 subjects deaths were registered, with a median survival time 36 months after the follow-up BS of 5 years. Subjects with low aBSI value had longer overall survival in comparison with the other subjects (P = 0.004). aBSI measurements were shown to be a strong prognostic survival indicator in PCa; survival is poor in high-BSI value.

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.

Prospective evaluation of computer-assisted analysis of skeletal lesions for the staging of prostate cancer

Background

The purpose of this study was to compare the agreement of the bone scan index (BSI) using EXINI Bone^BSI versus experts’ readings in the initial staging for bone metastasis in prostate cancer. In addition, the diagnostic outcome was assessed in a large subset of patients where a true reference for metastases could be determined based on clinical and biochemical follow-up and/or supplementary imaging.

Methods

A total of 342 patients had a bone scintigraphy as part of routine staging for prostate cancer. Supplementary imaging was obtained at the discretion of the referring urologist. After full recruitment, the BSI and the number of malignant lesions were calculated using EXINI Bone^BSI, and three imaging experts independently classified bone status by a dichotomous outcome (M1 for bone metastasis, M0 for no bone metastasis). A true reference was available in a subset of the patients based on post-operative prostate-specific antigen responses after radical prostatectomy and/or supplementary imaging.

Results

Software analysis with a BSI > 0 as the cut-off for metastasis showed excellent agreement with expert classification for M1 disease (96% of the patients) but modest agreement for M0 disease (38%). With a BSI > 1, the agreement was 58% for M1 and 98% for M0. Software analyses based on individual European Association of Urology risk classification did not improve the diagnostic performance. Among patients with a true reference, the software showed metastasis in 64% of the M0 patients but correctly classified metastases in all M1 patients. The sensitivity was 100%, the specificity was 36%, the positive predictive value was 12.6% and the negative predictive value was 100% with a BSI >0 compared with 66.7%, 97.8%, 72.7%, and 97.0% with a BSI > 1.

Conclusion

The diagnostic value of using EXINI Bone for the BSI in the staging of newly diagnosed prostate cancer is limited.

Use of a digital phantom developed by QIBA for harmonizing SUVs obtained from the state-of-the-art SPECT/CT systems: a multicenter study

BACKGROUND

Although quantitative analysis using standardized uptake value (SUV) becomes realistic in clinical single-photon emission computed tomography/computed tomography (SPECT/CT) imaging, reconstruction parameter settings can deliver different quantitative results among different SPECT/CT systems. This study aims to propose a use of the digital reference object (DRO), which is a National Electrical Manufacturers Association (NEMA) phantom-like object developed by the Quantitative Imaging Biomarker Alliance (QIBA) fluorodeoxyglucose-positron emission tomography technical committee, for the purpose of harmonizing SUVs in Tc-99m SPECT/CT imaging.

METHODS

The NEMA body phantom with determined Tc-99m concentration was scanned with the four state-of-the-art SPECT/CT systems. SPECT data were reconstructed using different numbers of the product of subset and iteration numbers (SI) and the width of 3D Gaussian filter (3DGF). The mean (SUV_mean), maximal (SUV_max), and peak (SUV_peak) SUVs for six hot spheres (10, 13, 17, 22, 28, and 37 mm) were measured after converting SPECT count into SUV using Becquerel calibration factor. DRO smoothed by 3DGF with a FWHM of 17 mm (DRO_17 mm) was generated, and the corresponding SUVs were measured. The reconstruction condition to yield the lowest root mean square error (RMSE) of SUV_means for all the spheres between DRO_17 mm and actual phantom images was determined as the harmonized condition for each SPECT/CT scanner. Then, inter-scanner variability in all quantitative metrics was measured before (i.e., according to the manufacturers' recommendation or the policies of their own departments) and after harmonization.

RESULTS

RMSE was lowest in the following reconstruction conditions: SI of 100 and 3DGF of 13 mm for Brightview XCT, SI of 160 and 3DGF of 3 pixels for Discovery NM/CT, SI of 60 and 3DGF of 2 pixels for Infinia, and SI of 140 and 3DGF of 15 mm for Symbia. In pre-harmonized conditions, coefficient of variations (COVs) among the SPECT/CT systems were greater than 10% for all quantitative metrics in three of the spheres, SUV_max and SUV_mean, in one of the spheres. In contrast, all metrics except SUV_max in the 17-mm sphere yielded less than 10% of COVs after harmonization.

CONCLUSIONS

Our proposed method clearly reduced inter-scanner variability in SUVs. A digital phantom developed by QIBA would be useful for harmonizing SUVs in multicenter trials using SPECT/CT.

Therapies for castration-resistant prostate cancer in a new era: The indication of vintage hormonal therapy, chemotherapy and the new medicines

When advanced prostate cancer recurred during hormonal therapy and became the castration-resistant prostate cancer, "vintage hormonal therapy," such as antiandrogen alternating therapy or estrogen-related hormonal therapy, was widely carried out in Japan until 2013. This vintage hormonal therapy controlled the progression of castration-resistant prostate cancer. When castration-resistant prostate cancer relapses during these therapies, chemotherapy using docetaxel has been carried out subsequently. Since new hormonal therapies using abiraterone acetate and enzalutamide, which improve the prognosis of castration-resistant prostate cancer, became available in Japan from 2014, therapeutic options for castration-resistant prostate cancer have increased. Furthermore, the improvement of the further prognosis is promising by using cabazitaxel for docetaxel-resistant castration-resistant prostate cancer and radium-223 for castration-resistant prostate cancer with bone metastasis. An increase in therapeutic options gives rise to many questions, including best timing to use them and the indication. Furthermore, physicians have to consider the treatment for the recurrence after having carried out chemotherapy. We want to argue the difference in hormonal therapy between Japan and Western countries, and problems when carrying out new treatments, and the importance of imaging in the present review article.

Diagnostic performance of a computer-assisted diagnosis system for bone scintigraphy of newly developed skeletal metastasis in prostate cancer patients: search for low-sensitivity subgroups

Purpose

The computer-assisted diagnostic system for bone scintigraphy (BS) BONENAVI is used to evaluate skeletal metastasis. We investigated its diagnostic performance in prostate cancer patients with and without skeletal metastasis and searched for the problems.

Methods

An artificial neural network (ANN) value was calculated in 226 prostate cancer patients (124 with skeletal metastasis and 101 without) using BS. Receiver operating characteristic curve analysis was performed and the sensitivity and specificity determined (cutoff ANN = 0.5). Patient’s situation at the time of diagnosis of skeletal metastasis, computed tomography (CT) type, extent of disease (EOD), and BS uptake grade were analyzed. False-negative and false-positive results were recorded.

Results

BONENAVI showed 82% (102/124) of sensitivity and 83% (84/101) specificity for metastasis detection. There were no significant differences among CT types, although low EOD and faint BS uptake were associated with low ANN values and low sensitivity. Patients showed lower sensitivity during the follow-up period than staging work-up. False-negative lesions were often located in the pelvis or adjacent to it. They comprised not only solitary, faint BS lesions but also overlaying to urinary excretion.

Conclusions

BONENAVI with BS has good sensitivity and specificity for detecting prostate cancer’s osseous metastasis. Low EOD and faint BS uptake are associated with low sensitivity but not the CT type. Prostate cancer patients likely to have false-negative results during the follow-up period had a solitary lesion in the pelvis with faint BS uptake or lesions overlaying to urinary excretion.

Expert System for Bone Scan Interpretation Improves Progression Assessment in Bone Metastatic Prostate Cancer

INTRODUCTION

The bone scan index (BSI) was introduced as a quantitative tool for tumor involvement in bone of patients with metastatic prostate cancer (mPCa). The computer-aided diagnosis device for BSI analysis EXINIbone^BSI seems to represent technical progress for the quantitative assessment of bone involvement. But it is not yet clear if the automated BSI (aBSI) could contribute to improved evaluation of progression in patients under antiandrogens or chemotherapy in contrast to the visual interpretation and/or conventional biomarkers such as the prostate-specific antigen (PSA).

METHODS

In 49 mPCa patients, bone scans were performed initially and during different therapy courses. Scans were evaluated visually and by the artificial-neural-network-based expert system EXINIbone^BSI. Progression of metastatic bone involvement was defined according to the Prostate Cancer Clinical Trials Working Group 2 (PCWG2) criteria in the visual interpretation. The computer-assisted interpretation was based on different cutoff values in relative changes of the aBSI. Additionally, assessments according to bone scanning were compared to changes in the PSA value as a potential surrogate for treatment response.

RESULTS

Using a sensitive cutoff value (5% or 10%) for the relative aBSI increase led to significantly increased progression determination compared to the visual interpretation of bone scans (49% and 43% vs. 27%, p < 0.001). In 63% of the cases PSA and BSI changes matched, whereas in 18% progression was only indicated by the aBSI. A relative cutoff of 5% for the aBSI decrease could reclassify 47 serial scan pairs which were visually interpreted as stable into 22 progressive and 25 remissive scans.

CONCLUSION

Distinct thresholds of the relative aBSI could help to better assess disease progression in mPCa patients. Manual corrections of the BSI values are not required in most cases. The aBSI could serve as a useful additional parameter for therapy monitoring in mPCa patients in the future.

Association between bone scan index and activities of daily living in patients with advanced non-small cell lung cancer

PURPOSE

The aim of this retrospective cross-sectional study was to investigate the association between the bone scan index (BSI) and activities of daily living (ADL) in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

Among patients with advanced NSCLC, subjects who underwent bone scintigraphy were recruited from this study. Clinical information about patients, including the Barthel Index of ADL, was extracted from their medical charts. Variables including the age, sex, BSI, presence/absence skeletal-related events (SREs), diagnostic state (initial vs. relapse), and history of use of certain medications (e.g. opiates) were evaluated as factors possibly associated with the Barthel Index. In Addition, associations between these factors, including the Barthel Index, with the overall survival were also assessed.

RESULTS

A total of 111 patients with bone metastases were selected. The BSI and Barthel Index of the patients were 1.59 ± 2.25 and 69.7 ± 19.6, respectively. Multivariable analysis identified age (≥70 years), a high BSI (≥1.0), and presence of SREs were as factors statistically significantly associated with lower values of the Barthel Index (<75). On the other hand, Cox proportional hazards analysis identified low values of the Barthel Index (<75), use of opiates, and male sex as significant factors associated with a shorter overall survival; the BSI was not associated with the overall survival in the patients with advanced NSCLC in this study.

CONCLUSION

The results suggest that a high BSI (≥1.0) is an independent predictor of poor ADL in patients with NSCLC, while showing no correlation with the overall survival.

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

PURPOSE

Bone scan index (BSI) is an objective tool for quantifying bone metastasis load. We assessed its prognostic usefulness in patients with metastatic castration-resistant prostate cancer (CRPC) treated with enzalutamide (ENZ) or abiraterone acetate (AA).

MATERIALS AND METHODS

We analyzed 40 patients who received ENZ or AA treatment (ENZ/AA) for metastatic CRPC. The Cox proportional hazards model and a C-index were used to investigate associations between overall survival (OS) and BSI, and patient age, prostate-specific antigen, time to CRPC, previous docetaxel use, and pain.

RESULTS

Median OS after ENZ/AA was 17.8 months. All patient deaths (n = 19; 47.5%) were from prostate cancer. In multivariate analysis, decreased BSI was an independent predictor for longer OS (hazard ratio, 8.97; P = .011). Inclusion of BSI improved the C-index from 0.721 to 0.792 in predicting OS after ENZ/AA.

CONCLUSIONS

Decreased BSI after ENZ/AA independently predicts longer OS.

Diagnostic utility of a computer-aided diagnosis system for whole-body bone scintigraphy to detect bone metastasis in breast cancer patients

OBJECTIVE

To compare the diagnostic ability of planar images (PI) and images obtained by a computer-aided diagnosis (CAD) system (Viewer for Standardized Bone Scintigraphies; VSBONE) of whole-body bone scintigraphy for detecting bone metastases in breast cancer patients.

METHODS

81 women (median: 56 years; range: 32-79) with a history of breast cancer were included in this study. They underwent whole-body bone scintigraphy after intravenous injection of 740 MBq technetium-99m hydroxymethylene diphosphonate. A total of 1066 bones (162 regions of the skull, 657 regions of the spine and pelvis, 223 regions of the sternum and rib, 18 regions of the upper extremities, and 6 regions of the lower extremities) were analyzed. The PI alone, VSBONE images alone, and both PI and VSBONE images (PI + VSBONE) were interpreted independently by two radiologists to diagnose bone metastases, which were then confirmed by magnetic resonance imaging. The sensitivity and specificity for each modality were analyzed using Fisher's exact and McNemar tests. Inter-reviewer agreement was evaluated using a kappa statistic.

RESULTS

Bone metastases were confirmed in 43 patients with 442 positive lesions. The average sensitivity of PI, VSBONE images, and PI + VSBONE images was 40.8, 50.2, and 61.8 %, respectively. The average specificity was 97.8, 97.5, and 97.6 %, respectively. The kappa scores were 0.62 for PI, 0.69 for VSBONE, and 0.77 for PI + VSBONE.

CONCLUSIONS

VSBONE was superior to PI in regard to sensitivity for detecting bone metastases in breast cancer patients. However, an improved CAD system is required to decrease the number of false-negative results.

Automated Bone Scan Index as a quantitative imaging biomarker in metastatic castration-resistant prostate cancer patients being treated with enzalutamide

Background

Having performed analytical validation studies, we are now assessing the clinical utility of the upgraded automated Bone Scan Index (BSI) in metastatic castration-resistant prostate cancer (mCRPC). In the present study, we retrospectively evaluated the discriminatory strength of the automated BSI in predicting overall survival (OS) in mCRPC patients being treated with enzalutamide.

Methods

Retrospectively, we included patients who received enzalutamide as a clinically approved therapy for mCRPC and had undergone bone scan prior to starting therapy. Automated BSI, prostate-specific antigen (PSA), hemoglobin (HgB), and alkaline phosphatase (ALP) were obtained at baseline. Change in automated BSI and PSA were obtained from patients who have had bone scan at week 12 of treatment follow-up. Automated BSI was obtained using the analytically validated EXINI Bone^BSI version 2. Kendall’s tau (τ) was used to assess the correlation of BSI with other blood-based biomarkers. Concordance index (C-index) was used to evaluate the discriminating strength of automated BSI in predicting OS.

Results

Eighty mCRPC patients with baseline bone scans were included in the study. There was a weak correlation of automated BSI with PSA (τ = 0.30), with HgB (τ = −0.17), and with ALP (τ = 0.56). At baseline, the automated BSI was observed to be predictive of OS (C-index 0.72, standard error (SE) 0.03). Adding automated BSI to the blood-based model significantly improved the C-index from 0.67 to 0.72, p = 0.017. Treatment follow-up bone scans were available from 62 patients. Both change in BSI and percent change in PSA were predictive of OS. However, the combined predictive model of percent PSA change and change in automated BSI (C-index 0.77) was significantly higher than that of percent PSA change alone (C-index 0.73), p = 0.041.

Conclusions

The upgraded and analytically validated automated BSI was found to be a strong predictor of OS in mCRPC patients. Additionally, the change in automated BSI demonstrated an additive clinical value to the change in PSA in mCRPC patients being treated with enzalutamide.

Prognostic value of the bone scan index using a computer-aided diagnosis system for bone scans in hormone-naive prostate cancer patients with bone metastases

BACKGROUND

The bone scan index (BSI) using a computer-aided diagnosis system for bone scans is expected to be an objective and quantitative clinical tool for evaluating bone metastatic prostate cancer. This study aimed to evaluate the pretreatment BSI as a prognostic factor in hormone-naive prostate cancer patients with bone metastases.

METHODS

The study included 60 patients with hormone-naive, bone metastatic prostate cancer that was initially treated with combined androgen blockade therapy. The BONENAVI system was used for calculating the BSI. We evaluated the correlation between overall survival (OS) and pretreatment clinicopathological characteristics, including patients' age, initial prostate-specific antigen (PSA) value, Gleason scores, clinical TNM stage, and the BSI. Cox proportional hazards regression models were used for statistical analysis.

RESULTS

The median follow-up duration was 21.4 months. Clinical or PSA progression occurred in 37 (61.7%) patients and 18 (30.0%) received docetaxel. Death occurred in 16 (26.7%) patients. Of these deaths, 15 (25.0%) were due to prostate cancer. The median OS was not reached. In multivariate analysis, age and the BSI were independent prognostic factors for OS. We evaluated the discriminatory ability of our models, including or excluding BSI by quantifying the C-index. The BSI improved the C-index from 0.751 to 0.801 for OS. Median OS was not reached in patients with a BSI ≤ 1.9 and median OS was 34.8 months in patients with a BSI >1.9 (p = 0.039).

CONCLUSIONS

The pretreatment BSI and patients' age are independent prognostic factors for patients with hormone-naive, bone metastatic prostate cancer.

Prognostic value of a computer-aided diagnosis system involving bone scans among men treated with docetaxel for metastatic castration-resistant prostate cancer

BACKGROUND

The bone scan index (BSI), which is obtained using a computer-aided bone scan evaluation system, is anticipated to become an objective and quantitative clinical tool for evaluating bone metastases in prostate cancer. Here, we assessed the usefulness of the BSI as a prognostic factor in patients with metastatic castration-resistant prostate cancer (mCRPC) treated using docetaxel.

METHODS

We analyzed 41 patients who received docetaxel for mCRPC. The Bonenavi system was used as the calculation program for the BSI. The utility of the BSI as a predictor of overall survival (OS) after docetaxel was evaluated. The Cox proportional hazards model was used to investigate the association between clinical variables obtained at docetaxel treatment, namely PSA, patient age, liver metastasis, local therapy, hemoglobin (Hb), lactase dehydrogenase (LDH), albumin (Alb), PSA doubling time, and BSI and OS.

RESULTS

The median OS after docetaxel therapy was 17.7 months. Death occurred in 22 (53.7%) patients; all deaths were caused by prostate cancer. In multivariate analysis, three factors were identified as significant independent prognostic biomarkers for OS after docetaxel; these were liver metastases (yes vs no; HR, 3.681; p = 0.026), Alb (<3.9 vs ≥ 3.9; HR, 3.776; p = 0.020), and BSI (>1% vs ≤ 1%; HR, 3.356; p = 0.037). We evaluated the discriminatory ability of our models including or excluding the BSI by quantifying the c-index. The BSI improved the c-index from 0.758 to 0.769 for OS after docetaxel. CRPC patients with a BSI >1 had a significantly shorter OS than patients with a BSI ≤ 1 (p = 0.029).

CONCLUSIONS

The BSI, liver metastases and Alb were independent prognostic factors for OS after docetaxel. The BSI might be a useful tool for risk stratification of mCRPC patients undergoing docetaxel treatment.

Assessment of anticancer-treatment outcome in patients with metastatic castration-resistant prostate cancer-going beyond PSA and imaging, a systematic literature review

BACKGROUND

In the past years, there has been significant progress in anticancer drug development for patients with metastatic castration-resistant prostate cancer (CRPC). However, the current instruments to assess clinical treatment response have limitations and may not sufficiently reflect patient benefit. Our objective was to systematically identify tools to evaluate both patient benefit and clinical anticancer-treatment response as basis for an international consensus process and development of a specific pragmatic instrument for men with CRPC.

METHODS

PubMed, Embase and CINAHL were searched to identify currently available tools to assess anticancer-treatment benefit, other than standard imaging procedures and prostate-specific antigen measurements, namely quality of life (QoL), detailed pain assessment, physical function and objective measures of other complex cancer-related syndromes in patients with CRPC. Additionally, all CRPC phase III trials published in the last 5 years were reviewed as well as studies using physical function tools in a general cancer population. The PRIMSA statement was followed for the systematic review process.

RESULTS

The search generated 1096 hits, 185 full-text papers were screened and finally 73 publications were included. Additional 89 publications were included by hand-search. We identified a total of 98 tools used in CRPC trials and grouped these into three categories: 22 tools assessing QoL domains and subgroups, 47 tools for pain assessment and 29 tools for objective measures, mainly physical function and assessment of skeletal disease burden.

CONCLUSION

A wide variety of assessment tools and also efforts to standardize and harmonize patient-reported outcomes and pain assessment were identified. However, the specific needs of the increasing CRPC population living longer with their incurable cancer are insufficiently captured and objective physical outcome measures are under-represented. In the age of new anticancer drug targets and principles, new methods to monitor patient relevant outcomes of antineoplastic therapy are of utmost importance.

Bone Scan Index as a prognostic imaging biomarker during androgen deprivation therapy

Background

Bone Scan Index (BSI) is a quantitative measurement of tumour burden in the skeleton calculated from bone scan images. When analysed at the time of diagnosis, it has been shown to provide prognostic information on survival in men with metastatic prostate cancer (PCa). In this study, we evaluated the prognostic value of BSI during androgen deprivation therapy (ADT).

Methods

Prostate cancer patients who were at high risk of a poor outcome and who had undergone bone scan at the time of diagnosis and during ADT were recruited from two university hospitals for a retrospective study. BSI at baseline and follow-up were calculated using an automated software package (EXINIbone^bsi). Associations between BSI, other prognostic biomarkers and overall survival (OS) were evaluated using a Cox proportional hazards regression model.

Results

One hundred forty-six PCa patients were included in the study. A total of 102 patient deaths were registered, with a median survival time after the follow-up bone scan of 2.4 years (interquartile range (IQR) =0.8 to 4.4). Both at baseline and during ADT, BSI was significantly associated with OS in univariate and multivariate analyses. When BSI was added to a prognostic base model including age, prostate-specific antigen, clinical tumour stage and Gleason score, the concordance index increased from 0.73 to 0.77 (p =0.0005) at baseline and from 0.77 to 0.82 (p <0.0001) during ADT.

Conclusions

Automated BSI during ADT is an independent prognostic indicator of OS in PCa patients with bone metastasis. It represents an emerging imaging biomarker that can be used in a prognostic model for risk stratification of PCa patients at the time of diagnosis and at later stages of the disease. BSI could then help physicians identify patients who could benefit from more aggressive therapies.