Predicting bone scan positivity in non-metastatic castration-resistant prostate cancer

Can We Predict Skeletal Lesion on Bone Scan Based on Quantitative PSMA PET/CT Features?

OBJECTIVE

The increasing use of PSMA-PET/CT for restaging prostate cancer (PCa) leads to a patient shift from a non-metastatic situation based on conventional imaging (CI) to a metastatic situation. Since established therapeutic pathways have been designed according to CI, it is unclear how this should be translated to the PSMA-PET/CT results. This study aimed to investigate whether PSMA-PET/CT and clinical parameters could predict the visibility of PSMA-positive lesions on a bone scan (BS).

METHODS

In four different centers, all PCa patients with BS and PSMA-PET/CT within 6 months without any change in therapy or significant disease progression were retrospectively selected. Up to 10 non-confluent clear bone metastases were selected per PSMA-PET/CT and SUVmax, SUVmean, PSMAtot, PSMAvol, density, diameter on CT, and presence of cortical erosion were collected. Clinical variables (age, PSA, Gleason Score) were also considered. Two experienced double-board physicians decided whether a bone metastasis was visible on the BS, with a consensus readout for discordant findings. For predictive performance, a random forest was fit on all available predictors, and its accuracy was assessed using 10-fold cross-validation performed 10 times.

RESULTS

A total of 43 patients were identified with 222 bone lesions on PSMA-PET/CT. A total of 129 (58.1%) lesions were visible on the BS. In the univariate analysis, all PSMA-PET/CT parameters were significantly associated with the visibility on the BS (p < 0.001). The random forest reached a mean accuracy of 77.6% in a 10-fold cross-validation.

CONCLUSIONS

These preliminary results indicate that there might be a way to predict the BS results based on PSMA-PET/CT, potentially improving the comparability between both examinations and supporting decisions for therapy selection.

18F-DCFPyL PET/CT guidelines

The objective of this guide is to provide to nuclear medicine physicians a tool based on scientific evidence and prepared by consensus of experts, to perform the ¹⁸F-DCFPyL PET/CT procedure with safely and efficiently for patients with prostate cancer who present PSMA overexpression. For them, some recommendations will be established for ¹⁸F-DCFPyL PET/CT examination: reconstruction parameters, presentation of the images and their interpretation. The possible false positives of the procedure will be analysed, how to interpret them and how to avoid them. Finally, all exploration should lead to the preparation of a report that answers the clinician's question. For this, it is recommended to prepare a structured report that includes the PROMISE criteria as well as the classification of the findings according to PSMA-RADS parameters.

Efficacy and Safety of Darolutamide in Patients with Nonmetastatic Castration-resistant Prostate Cancer Stratified by Prostate-specific Antigen Doubling Time: Planned Subgroup Analysis of the Phase 3 ARAMIS Trial

BACKGROUND

Patients with nonmetastatic castration-resistant prostate cancer (nmCRPC) have a high risk of progression to metastatic disease, particularly if their prostate-specific antigen doubling time (PSADT) is ≤6 mo. However, patients remain at a high risk with a PSADT of >6 mo.

OBJECTIVE

To evaluate the efficacy and safety of darolutamide versus placebo in patients stratified by PSADT >6 or ≤6 mo.

DESIGN, SETTING, AND PARTICIPANTS

A planned subgroup analysis of a global multicenter, double-blind, randomized, phase 3 trial in men with nmCRPC and PSADT ≤10 mo was conducted.

INTERVENTION

Patients were randomized 2:1 to oral darolutamide 600 mg twice daily or placebo, while continuing androgen-deprivation therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was metastasis-free survival (MFS). Secondary endpoints were overall survival (OS) and times to pain progression, first cytotoxic chemotherapy, and symptomatic skeletal events. Quality of life (QoL) was measured using validated prostate-relevant tools. Safety was recorded throughout the study.

RESULTS AND LIMITATIONS

Of 1509 patients enrolled, 469 had PSADT >6 mo (darolutamide n = 286; placebo n = 183) and 1040 had PSADT ≤6 mo (darolutamide n = 669; placebo n = 371). Baseline characteristics were balanced between subgroups. Darolutamide significantly prolonged MFS versus placebo in both subgroups (unstratified hazard ratio [95% confidence interval]: PSADT >6 mo, 0.38 [0.26-0.55]; PSADT ≤6 mo, 0.41 [0.33-0.52]). OS and other efficacy and QoL endpoints favored darolutamide with significant improvement over placebo in both subgroups. The incidence of adverse events, including events commonly associated with androgen receptor inhibitors (fractures, falls, hypertension, and mental impairment), and discontinuations due to adverse events were low and similar to placebo. Limitations include small subgroup populations.

CONCLUSIONS

In patients with nmCRPC and PSADT >6 mo (maximum 10 mo), darolutamide provided a favorable benefit/risk ratio, characterized by significant improvements in MFS, OS, and other clinically relevant endpoints; maintenance of QoL; and favorable tolerability.

PATIENT SUMMARY

In patients with prostate cancer that has stopped responding to standard hormonal therapy (indicated by an increase in prostate-specific antigen [PSA] levels), there is a risk that the cancer will spread to other parts of the body. This risk is highest when the time it takes for the PSA level to double (ie, "PSA doubling time" [PSADT]) is less than 6 mo. However, there is still a risk that the cancer will spread even if the PSADT is longer than 6 mo. In a group of patients whose PSADT was more than 6 mo but no more than 10 mo, treatment with darolutamide slowed the cancer spread and allowed them to live longer than patients who received placebo (inactive drug). Darolutamide treatment did not cause many side effects and helped maintain patients' quality of life without disruptions.

nmCRPC, a look in the continuous care of prostate cancer patients: state of art and future perspectives

Non-metastatic castration resistant prostate cancer (nmCRPC) is a clinical setting defined as confirmed rising levels of PSA in patients treated with ADT but without detectable metastases on conventional imaging with computerized tomography (CT) and technetium-99 m scintigraphy. Men with nmCRPC and a PSA doubling time (PSADT) ≤ 10 months are considered at high risk of rapidly developing metastases with a consequent possible impact on survival. Three recent phase III trials have demonstrated, in this setting, the efficacy of adding a next-generation androgen receptor targeted agent (ARTA) to ADT in respect to ADT only, in delaying the development of metastases (metastasis-free survival, MFS) and prolong overall survival. The magnitude of clinical benefit of these agents was even more meaningful if considering the low incidence of drug related adverse events. Our review described the latest advances in the management of nmCRPC, deriving from the pivotal clinical trials, SPARTAN, PROSPER and ARAMIS, in order to support clinicians to optimally manage these patients. Of note, the emergence of novel, more accurate, next-generation imaging techniques (including Ga PSMA-PET/CT), as well as eventual future tumor biomarkers, is modifying the entity and definition of the nmCRPC setting, with a consequent impact on patient's diagnosis and management.

Survival and Economic Impact of Rapid Prostate-Specific Antigen Doubling Time in Patients With Nonmetastatic Castration-Resistant Prostate Cancer

INTRODUCTION

In patients with nonmetastatic castration-resistant prostate cancer (nmCRPC), prostate-specific antigen doubling time (PSADT) is associated with risk of metastasis and survival. This study evaluated the association of PSADT with clinical and economic outcomes in a real-world setting among patients with nmCRPC not receiving novel hormonal therapy (NHT), using 2-month PSADT thresholds.

PATIENTS AND METHODS

We retrospectively identified Veterans Health Administration patients with nonmetastatic prostate cancer and ≥2 PSA increases after medical/surgical castration (2012-2016). The third measurement was the index (CRPC) date. Patients with ≥3 postindex PSA measurements, including index, were followed until death or ≥12 months until disenrollment, study end, or death, and grouped into 2-month cohorts based on postindex PSADT. Cox regression models assessed association between PSADT, time to metastasis, and death. Healthcare resource utilization and costs were evaluated.

RESULTS

Among 2800 evaluable patients, median follow-up was 30 months and median PSADT was 17 months. Relative to the reference cohort (PSADT >12 months), all cohorts had significantly higher metastasis risk. PSADT ≤10-month cohorts had significantly greater mortality risk than the reference; hazard ratios (95% confidence intervals) ranged from 12.3 (9.2, 16.4) in the PSADT ≤2-month cohort to 1.3 (0.9, 2.0) in the >10 to ≤12-month cohort. Total costs were significantly higher for cohorts up to and including the PSADT >8 to ≤10-month cohort, than for the reference cohort. Mean per patient per month all-cause medical plus pharmacy costs were $6623, $4768, and $4049 in the PSADT ≤2-month, >2 to ≤4-month cohort, and >4 to ≤6-month cohorts, respectively, versus $1911 in the PSADT >12-month cohort (P <0.05).

CONCLUSION

Most patients with nmCRPC have PSADT >12 months and a long natural history. For those with shorter PSADT, the risk of metastasis, death, and costs increased. These data can help select patients for NHT and conversely those who can safely delay NHT for nmCRPC.

How PET-CT is Changing the Management of Non-metastatic Castration-resistant Prostate Cancer?: Comment la TEP-TDM Peut Modifier la Prise en Charge du Cancer de la Prostate Non Métastatique Résistant à la Castration ?

INTRODUCTION

The aim of this narrative review conducted by the Prostate Cancer Committee of the French Association of Urology (CC-AFU) was to provide an update on the current evidence for the impact of PET/CT in the management of men with non-metastatic castration-resistant prostate cancer (nmCRPC).

MATERIAL AND METHODS

This review is based on data available in the literature on PET/CT imaging for staging nmCRPC patients. A PubMed search and narrative review of the data were performed in March 2022. Only articles in French or English were considered.

RESULTS

Current guidelines recommend bone scan and CT scan as standard imaging modalities for staging and follow-up of patients with nmCRPC. Nearly one-third of asymptomatic patients with presumed nmCRPC ultimately have metastatic disease on conventional imaging. Increasing reports have shown that conventional imaging has limited accuracy in detecting metastatic disease in nmCRPC patients, leading to the development of next-generation imaging techniques. In a retrospective study, 18F-choline PET/CT detected distant metastases in 27/58 high-risk nmCRPC patients with prior negative conventional imaging. The implementation of radiolabeled ligands of the prostate-specific membrane antigen (PSMA) PET/CT in staging strategy has resulted in metastasis detection in 45% to 98% of patients with presumptive nmCRPC on conventional imaging. Such an early diagnosis of metastatic CRPC may allow patients to be referred for metastasis-directed therapies (i.e. stereotactic body radiotherapy), aimed at prolonging the efficacy of systemic therapies and improving clinical outcomes. However, current data are not strong enough to recommend this strategy, which must be properly evaluated in clinical trials. Indeed, the use of molecular imaging may lead to inappropriate undertreatment if the second-generation androgen receptor inhibitors (darolutamide, enzalutamide, apalutamide), which prolong life, are not used in the subgroup of patients with high PSA velocity (PSA doubling time <10 months).

CONCLUSION

Implementation of PSMA-PET/CT in the staging strategy would result in a migration of disease stage to extra-pelvic, M1 disease in at least half of presumed nmCRPC patients. The unprecedented accuracy of PSMA-PET/CT may pave the way for a more personalized treatment strategy. However, no data yet support this strategy for all nmCRPC patients as no oncologic benefit of early detection of M1 disease or MDT has been demonstrated. © 2022 Elsevier Masson SAS. All rights reserved.

Does whole-body bone SPECT/CT provide additional diagnostic information over [18F]-FCH PET/CT for the detection of bone metastases in the setting of prostate cancer biochemical recurrence?

BACKGROUND

To assess whether whole-body (WB) bone SPECT/CT provides additional diagnostic information over [18F]-FCH PET/CT for the detection of bone metastases in the setting of prostate cancer biochemical recurrence (PC-BR).

METHODS

Patients referred for a PC-BR and whom benefited from a WB bone SPECT/CT and FCH PET/CT were retrospectively included. Tests were classified as positive, equivocal, or negative for bone metastases. A best valuable comparator (BVC) strategy including imaging and follow-up data was used to determine the metastatic status in the absence of systematic histological evaluation.

RESULTS

Between January 2011 and November 2017, 115 consecutive patients with a PC-BR were evaluated. According to the BVC, 30 patients had bone metastases and 85 patients did not present with bone lesions. The sensitivity, specificity, positive and negative predictive values were respectively 86.7% [69.3-96.2], 98.8% [93.6-100.0], 96.3% [78.7-99.5], and 95.5% [89.4-98.1] for WB bone SPECT/CT and 93.3% [77.9-99.2], 100.0% [95.8-100.0], 100.0 and 97.7% [91.8-99.4] for FCH PET/CT. There was no significant difference in diagnostic accuracy of bone metastases between WB Bone SPECT/CT (AUC 0.824 [0.74-0.90]) and FCH PET/CT (AUC 0.829 [0.75-0.90], p = 0.41).

CONCLUSION

Despite good performances for the diagnosis of bone metastases in PC-BR, WB bone SPECT/CT does not provide additive diagnostic information over concomitant FCH PET/CT.

Predictors of survival, healthcare resource utilization, and healthcare costs in veterans with non-metastatic castration-resistant prostate cancer

OBJECTIVES

The objective of this study was to evaluate the association of prostate-specific antigen doubling time (PSADT) with metastasis-free survival (MFS) and overall survival (OS), and to describe healthcare resource utilization (HRU) and costs among patients with non-metastatic castrate-resistant prostate cancer (nmCRPC) in the Veterans Health Administration setting.

METHODS AND MATERIALS

Patients with nmCRPC were identified from the Veterans Health Administration electronic health record database (1/2007-8/2017). PSADT was categorized as <3 months, 3 to 9 months, 9 to 15 months, ≥15 months, and unknown. MFS and OS were assessed using multivariable Cox proportional hazards regression, including PSADT as a predictor. HRU and costs were described per-patient-per-year (PPPY).

RESULTS

Among 12,083 patients in the study, shorter PSADT was associated with shorter MFS and OS (PSADT <3 months vs. PSADT ≥15 months hazard ratio [HR] [95% confidence interval (CI)] = 0.307 [0.281, 0.335] and 0.371 [0.335, 0.410], respectively). Patients who developed metastasis had a 3-fold higher risk of death compared to those without metastasis (HR [95% CI] = 2.933 [2.763, 3.113]). Mean HRU increased following the onset of nmCRPC and metastatic castrate-resistant prostate cancer (mCRPC); mean inpatient stays more than doubled (0.2 vs. 0.5 and 0.6 vs. 2.8 PPPY, respectively). Similar increases in healthcare costs were observed; pharmacy costs more than tripled following nmCRPC ($2,074 vs. $6,839 PPPY). From nmCRPC to mCRPC, large increases were observed for inpatient costs ($7,257-$61,691), emergency room costs ($844-$1,958), and pharmacy costs ($4,115-$26,279) PPPY.

CONCLUSIONS

In Veterans with nmCRPC, shorter PSADT was significantly associated with shorter MFS and OS. Onset of nmCRPC and mCRPC was associated with substantial HRU and cost increases.

Bone scan positivity in non-metastatic, castrate-resistant prostate cancer: external validation study

INTRODUCTION

Tables predicting the probability of a positive bone scan in men with non-metastatic, castrate-resistant prostate cancer have recently been reported. We performed an external validation study of these bone scan positivity tables.

MATERIALS AND METHODS

We performed a retrospective cohort study of patients seen at a tertiary care medical center (1996-2012) to select patients with non-metastatic, castrate-resistant prostate cancer. Abstracted data included demographic, anthropometric, and disease-specific data such as patient race, BMI, PSA kinetics, and primary treatment. Primary outcome was metastasis on bone scan. Multivariable logistic regression was performed using generalized estimating equations to adjust for repeated measures. Risk table performance was assessed using ROC curves.

RESULTS

We identified 6.509 patients with prostate cancer who had received hormonal therapy with a post-hormonal therapy PSA ≥2ng/mL, 363 of whom had non-metastatic, castrate-resistant prostate cancer. Of these, 187 patients (356 bone scans) had calculable PSA kinetics and ≥1 bone scan. Median follow-up after castrate-resistant prostate cancer diagnosis was 32 months (IQR: 19-48). There were 227 (64%) negative and 129 (36%) positive bone scans. On multivariable analysis, higher PSA at castrate-resistant prostate cancer (4.67 vs. 4.4ng/mL, OR=0.57, P=0.02), shorter time from castrate-resistant prostate cancer to scan (7.9 vs. 14.6 months, OR=0.97, P=0.006) and higher PSA at scan (OR=2.91, P<0.0001) were significantly predictive of bone scan positivity. The AUC of the previously published risk tables for predicting scan positivity was 0.72.

CONCLUSION

Previously published risk tables predicted bone scan positivity in men with non-metastatic, castrate-resistant prostate cancer with reasonable accuracy.

Diagnosis of metastasis in castration-resistant prostate cancer patients: decision algorithm in imaging tests

INTRODUCTION

In castration-resistant prostate cancer (CRPC), early detection of metastases is essential for the selection of treatment, and prevention of bone complications. However detecting incipient metastases remains a challenge as the conventional radiological tests (bone scintigraphy or computerised tomography) lack sufficient sensitivity. Diagnostic imaging techniques are currently available that have greater sensitivity and specificity, but are little used due to shortfalls in the recommendations.

OBJECTIVE

To create an algorithm that indicates the most suitable diagnostic imaging techniques for the different M0 CRPC patient profiles based on the scientific evidence.

EVIDENCE ACQUISITION

Meetings were held with eight experts in Urology, Pathological Anatomy, Radiodiagnostics and Nuclear Medicine organised by the Andalusian Association of Urology, in which the recommendations and scientific evidence on each of the diagnostic imaging techniques were reviewed.

SUMMARY OF THE EVIDENCE

We present the current recommendations for the detection of metastasis in M0 CRPC patients, the patients that would benefit from early detection, and summarise the evidence to support the use of each of the new techniques.

CONCLUSIONS

Techniques such as ¹⁸F-Choline PET/CT or DWWB MRI and probably open MRI have been demonstrated to have good sensitivity and specificity for patients with low PSA (<10ng/ml). Their inclusion in routine clinical practice will help improve the early detection of metastasis in CRPC patients.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Impact of age, comorbidity, and PSA doubling time on long-term competing risks for mortality among men with non-metastatic castration-resistant prostate cancer

BACKGROUND

Understanding competing risks for mortality is critical in determining prognosis among men with non-metastatic castration-resistant prostate cancer (nmCRPC), a disease state that often affects older men and has substantial heterogeneity in risk of cancer mortality. We sought to determine the impact of age, comorbidity, and PSA doubling time (PSADT) on competing risks for mortality in men with nmCRPC.

METHODS

We conducted a retrospective analysis of 1238 patients diagnosed with nmCRPC in 2000-2015 in the SEARCH database. Multivariable Cox proportional hazards and competing risks regression were used to determine the hazards of overall, prostate cancer-specific (PCSM), and other-cause mortality (OCM) across age, Charlson comorbidity index (CCI), and PSADT subgroups.

RESULTS

Men with nmCRPC were elderly (median age 77) and had substantial comorbidity burdens (CCI > 1 n = 701, 57%). Multivariable Cox analysis showed higher CCI was associated with higher hazard of OCM, while slower PSADT was associated with lower hazard of PCSM across all age subgroups. Among those with CCI ≥ 3 (vs. CCI0), the hazard ratio of OCM was 2.7 (95% CI 1.1-6.3), 2.0 (95% CI 1.1-3.6), and 2.5 (95% CI 1.5-4.0) for those aged <70, 70-79, and ≥80, respectively. Among those with PSADT ≥ 9 months (vs. < 9 months), the hazard ratios for PCSM were 0.5 (95% CI 0.3-0.9), 0.6 (95% CI 0.4-0.9), and 0.6 (95% CI 0.4-0.9) for those aged <70, 70-79, and ≥80. Competing risks curves revealed PCSM was the predominant cause of death for those with PSADT < 9 months across all age and comorbidity groups. PCSM and OCM were relatively equal competitors for mortality among those with PSADT≥9 months except those aged > 80 with CCI ≥ 3, in whom OCM was the predominant cause of death.

CONCLUSIONS

Among men with nmCRPC, age, comorbidity, and PSADT are associated with risk and cause of death and may assist clinicians in counseling patients regarding cancer prognosis.

Thresholds for PSA doubling time in men with non-metastatic castration-resistant prostate cancer

OBJECTIVES

To examine whether prostate-specific antigen doubling time (PSADT) correlates with metastases, all-cause mortality (ACM), and prostate cancer-specific mortality (PCSM) and to identify PSADT thresholds that can be used clinically for risk stratification in men with M0 castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

We collected data on 441 men with M0 CRPC in 2000-2015 at five Veterans Affairs hospitals. Cox models were used to test the association between log-transformed PSADT and the development of metastasis, ACM and PCSM. To identify thresholds, we categorized PSADT into 3-month groups and then combined groups with similar hazard ratios (HRs).

RESULTS

The median (interquartile range) follow-up was 28.3 (14.7-49.1) months. As a continuous variable, PSADT was associated with metastases, ACM and PCSM (HR 1.40-1.68, all P < 0.001). We identified the following PSADT thresholds: <3 months; 3-8.9 months; 9-14. months; and ≥15 months. As a categorical variable, PSADT was associated with metastases, ACM and PCSM (all P < 0.001). Specifically, PSADT <3 months was associated with an approximately ninefold increased risk of metastases (HR 8.63, 95% CI 5.07-14.7) and PCSM (HR 9.29, 95% CI 5.38-16.0), and a 4.7-fold increased risk of ACM (HR 4.71, 95% CI 2.98-7.43) on multivariable analysis compared with PSADT ≥15 months. The median times to metastasis for patients with PSADT <3, 3-8.9, 9-14.9 and ≥15 months were 9, 19, 40 and 50 months, respectively.

CONCLUSION

Prostate-specific antigen doubling time was a strong predictor of metastases, ACM and PCSM in patients with M0 CRPC. As with patients at earlier disease stages, <3, 3-8.9, 9-14.9 and ≥15 months are reasonable PSADT thresholds for risk stratification in men with M0 CRPC. These thresholds can be used for selecting high-risk men for clinical trials.

Number of Unfavorable Intermediate-Risk Factors Predicts Pathologic Upstaging and Prostate Cancer-Specific Mortality Following Radical Prostatectomy: Results From the SEARCH Database

BACKGROUND

To validate and further improve the stratification of intermediate risk prostate cancer into favorable and unfavorable subgroups for patients undergoing radical prostatectomy.

MATERIALS AND METHODS

The SEARCH database was queried for IR patients undergoing radical prostatectomy without adjuvant radiotherapy. UIR disease was defined any patient with at least one unfavorable risk factor (URF), including primary Gleason pattern 4, 50% of more biopsy cores containing cancer, or multiple National Comprehensive Cancer Network IR factors.

RESULTS

One thousand five hundred eighty-six patients with IR prostate cancer comprised the study cohort. Median follow-up was 62 months. Patients classified as UIR were significantly more likely to have pathologic high-risk features, such as Gleason score 8 - 10, pT3-4 disease, or lymph node metastases, than FIR patients (P < 0.001). Furthermore, UIR patients had significantly higher rates of PSA-relapse (PSA, hazard ratio [HR] = 1.89, P < 0.001) and distant metastasis (DM, HR = 2.92, P = 0.001), but no difference in prostate cancer-specific mortality (PCSM) or all-cause mortality in multivariable analysis. On secondary analysis, patients with ≥2 URF had significantly worse PSA-RFS, DM, and PCSM than those with 0 or 1 URF. Moreover, 40% of patients with ≥2 URF had high-risk pathologic features.

CONCLUSIONS

Patients with UIR prostate cancer are at increased risk of PSA relapse, DM, and pathologic upstaging following prostatectomy. However, increased risk of PCSM was only detected in those with ≥2 URF. This suggests that further refinement of the UIR subgroup may improve risk stratification. Prostate Prostate 77:154-163, 2017. © 2016 Wiley Periodicals, Inc.

Factors predicting skeletal-related events in patients with bone metastatic castration-resistant prostate cancer

BACKGROUND

Skeletal-related events (SREs) are common complications of bone metastatic castration-resistant prostate cancer (mCRPC). To the authors' knowledge, there are limited data regarding which factors predict SREs. The authors identified risk factors for SREs in men with bone mCRPC using characteristics commonly available in the medical record.

METHODS

Data from 454 patients with nonmetastatic CRPC were identified from 2 Veteran Affairs Medical Centers from 2000 through 2013. Among these men, 233 (51%) developed bone metastases during follow-up and represented the study cohort. First occurrence of an SRE was abstracted from the medical records. A stepwise multivariable Cox model was used to select the strongest predictors of time to SRE.

RESULTS

The median age of the patients at the time of diagnosis of bone mCRPC was 75 years (interquartile range, 68-81 years), and there were 153 nonblack patients (66%). During follow-up (median, 7.8 months [interquartile range, 2.9-18.3 months]), 88 patients (38%) had an SRE. On univariable analysis, more recent year of metastasis (hazard ratio [HR], 0.91), prostate-specific antigen doubling time of ≥9 months versus <9 months (HR, 0.50), and bone pain (HR, 3.34) were all found to be associated with SRE risk. On multivariable analysis, year of metastasis (HR, 0.93), biopsy Gleason score of 7 versus ≤6 (HR, 1.74), radiotherapy as the primary localized treatment versus none (HR, 2.33), and bone pain (HR, 3.64) were associated with SRE risk. The area under the curve for a multivariable model based upon these risk factors was 0.744.

CONCLUSIONS

The authors identified several significant predictors of SREs among men with mCRPC. In particular, men with bone pain are at high risk of an SRE. If confirmed, future trials should focus on prolonging life and reducing SRE risk in patients with mCRPC with bone pain. Cancer 2017;123:1528-1535. © 2017 American Cancer Society.

Predictors of Time to Metastasis in Castration-resistant Prostate Cancer

OBJECTIVE

To investigate predictors of time to metastasis among men treated with androgen deprivation therapy for nonmetastatic prostate cancer who developed castration-resistant prostate cancer (CRPC) within the Shared Equal Access Regional Cancer Hospital cohort.

METHODS

This is a retrospective analysis of 458 nonmetastatic CRPC men. Metastases were detected in routine bone scans or other imaging tests. Predictors of time to metastasis were analyzed using proportional hazards model with CRPC as time zero.

RESULTS

A total of 256 (56%) men were diagnosed with metastatic disease over a median follow-up of 36 months. Metastasis-free survival was 79%, 65%, 52%, 47%, and 41% at 1, 2, 3, 4, and 5 years after CRPC, respectively. In multivariable analysis, Gleason score 8-10 (hazard ratio [HR] = 1.61; P = .026), receiving primary localized treatment (HR = 1.38; P = .028), higher prostate-specific antigen (PSA) levels at CRPC diagnosis (logPSA HR = 1.64; P < .001), and PSA doubling time ≤6 months (HR = 1.42; P = .040) were independently associated with shorter time to metastasis. Race, year of CRPC, age, and time from androgen deprivation therapy to CRPC were not associated with metastasis.

CONCLUSION

Among nonmetastatic CRPC men, nearly 60% developed metastatic disease during the first 5 years, with most of the metastasis occurring within the first 3 years. Higher Gleason score, receiving primary treatment, higher PSA, and shorter PSA doubling time were independently associated with shorter time to metastasis. Therefore, these variables can be used to stratify patients according to metastasis risk.

Predicting Time From Metastasis to Overall Survival in Castration-Resistant Prostate Cancer: Results From SEARCH

OBJECTIVE

To identify the predictors of time from initial diagnosis of metastatic castration-resistance prostate cancer (mCRPC) to all-cause death within the Shared Equal Access Regional Cancer Hospital cohort.

PATIENTS AND METHODS

We performed a retrospective analysis of 205 mCRPC men. Overall survival was estimated and plotted using the Kaplan-Meier method. The uni- and multivariable overall survival predictors were evaluated with the Cox proportional hazards model. A nomogram was generated to predict overall survival at 1, 2, 3, and 5 years after mCRPC. Concordance index and calibration plot were obtained.

RESULTS

A total of 170 men (83%) died over a median follow-up of 41 months. In univariable analysis, older age, more remote year of mCRPC, nonblack race, greater number of bone metastasis, higher prostate-specific antigen (PSA) levels, shorter PSA doubling time, and faster PSA velocity at mCRPC diagnosis were significantly associated with shorter overall survival (all P < .05). In multivariable analysis, older age, more remote year of mCRPC, greater number of bone metastasis, higher PSA levels, and shorter PSA doubling time at mCRPC diagnosis remained significantly associated with shorter overall survival (all P < .05). On the basis of these variables, a nomogram was generated yielding a concordance index of 0.67 and good calibration.

CONCLUSION

The use of clinical parameter such as age, disease burden, and PSA levels and kinetics can be used to estimate overall survival in mCRPC patients.

Detecting Tumor Metastases: The Road to Therapy Starts Here

Metastasis is the complex process by which primary tumor cells migrate and establish secondary tumors in an adjacent or distant location in the body. Early detection of metastatic disease and effective therapeutic options for targeting these detected metastases remain impediments to effectively treating patients with advanced cancers. If metastatic lesions are identified early, patients might maximally benefit from effective early therapeutic interventions. Further, monitoring patients whose primary tumors are effectively treated for potential metastatic disease onset is also highly valuable. Finally, patients with metastatic disease can be monitored for efficacy of specific therapeutic interventions through effective metastatic detection techniques. Thus, being able to detect and visualize metastatic lesions is key and provides potential to greatly improve overall patient outcomes. In order to achieve these objectives, researchers have endeavored to mechanistically define the steps involved in the metastatic process as well as ways to effectively detect metastatic progression. We presently overview various preclinical and clinical in vitro and in vivo assays developed to more efficiently detect tumor metastases, which provides the foundation for developing more effective therapies for this invariably fatal component of the cancerous process.

Do skeletal-related events predict overall survival in men with metastatic castration-resistant prostate cancer?

BACKGROUND

Skeletal-related events (SREs) including pathologic fracture, spinal cord compression, radiation to bone and surgery to bone, are common in men with bone metastatic castration-resistant prostate cancer (mCRPC). Men with mCRPC are at high risk of death. Whether SREs predict mortality is unclear. We tested the association between SREs and overall survival (OS) in a multiethnic cohort with bone mCRPC, controlling for key covariates unavailable in claims data such as bone pain, number of bone metastases and PSA doubling time (PSADT).

METHODS

We collected data on 233 men diagnosed with nonmetastatic castration-resistant prostate cancer (CRPC) in 2000-2013 at two Veterans Affairs hospitals who later progressed to bone metastases. First occurrence of SRE and OS were collected from the medical records. Cox models were used to test the association between SRE and OS, treating SRE as a time-dependent variable. We adjusted for age, year, race, treatment center, biopsy Gleason, primary treatment to the prostate, PSA, PSADT, months from androgen deprivation therapy to CRPC, months from CRPC to metastasis and number of bone metastases at initial bone metastasis diagnosis. In a secondary analysis, we also adjusted for bone pain.

RESULTS

During follow-up, 88 (38%) patients had an SRE and 198 (85%) died. After adjusting for risk factors, SRE was associated with increased mortality (hazard ratio (HR)=1.67; 95% confidence interval (CI) 1.22-2.30; P=0.001). When bone pain was added to the model, the association of SREs and OS was attenuated, but remained significant (HR=1.42; 95% CI 1.01-1.99; P=0.042).

CONCLUSIONS

SREs are associated with increased mortality in men with bone mCRPC. Further studies on the impact of preventing SREs to increase survival are warranted.

Validation of a bone scan positivity risk table in non-metastatic castration-resistant prostate cancer

OBJECTIVES

To test the external validity of a previously developed risk table, designed to predict the probability of a positive bone scan among men with non-metastatic (M0) castration-resistant prostate cancer (CRPC), in a separate cohort.

PATIENTS AND METHODS

We retrospectively analysed 429 bone scans of 281 patients with CRPC, with no known previous metastases, treated at three Veterans Affairs Medical Centers. We assessed the predictors of a positive scan using generalized estimating equations. Area under the curve (AUC), calibration plots and decision-curve analysis were used to assess the performance of our previous model to predict a positive scan in the current data.

RESULTS

A total of 113 scans (26%) were positive. On multivariable analysis, the only significant predictors of a positive scan were log-transformed prostate-specific antigen (PSA): hazard ratio (HR) 2.13; 95% confidence interval (CI) 1.71-2.66 (P < 0.001) and log-transformed PSA doubling time (PSADT): HR 0.53; 95% CI 0.41-0.68 (P < 0.001). Among men with a PSA level <5 ng/mL, the rate of positive scans was 5%. The previously developed risk table had an AUC of 0.735 to predict positive bone scan with excellent calibration, and provided additional net benefit in the decision-curve analysis.

CONCLUSION

We have validated our previously developed table to predict the risk of a positive bone scan among men with M0/Mx CRPC. Use of this risk table may allow better tailoring of patients' scanning to identify metastases early, while minimizing over-imaging. Regardless of PSADT, positive bone scans were rare in men with a PSA <5 ng/mL.