Predictors of clinical metastasis in prostate cancer patients receiving androgen deprivation therapy: results from CaPSURE

Quantifying the survival benefit of completing all the six cycles of radium-223 therapy in patients with castrate-resistant prostate cancer with predominant bone metastases

A retrospective analysis was performed of epidemiological data assessing the survival of patients who had received radium-223 for castrate-resistant metastatic prostate cancer treated at a regional tertiary referral center over a 5-year period. The patients' age, date of first treatment, and the number of cycles of radium-223 given were obtained from the patients' electronic patient record (EPR). Data on the date of death were provided by national death registrations which update the EPR via a unique national health service number. A total of 187 patients (mean age on the date of first treatment: 73 years; range: 56-93) were treated from April 1, 2014, to June 30, 2019. The median overall survival of the 119 patients (71%) who had died by December 31, 2019, was 15 months. There was no significant age difference between those who had died and survivors (72 vs. 74 years). On a further analysis, it was found that the median overall survival of the 107 patients who had received all the six cycles of radium-223 was 31 months, significantly longer than the median overall survival of only 6 months for those eighty patients who had received less than the full course of six cycles of radium-223 (P = 0.001). Of those who received all the six cycles of treatment, 58 patients had died (58%) and the 1-year survival was 87%. This was compared to the group of patients receiving <6 cycles of radium-223 where 61 patients (76%) had died and the 1-year survival was 30%. Therefore, the hazard ratio of dying before 1 year if the patient did not receive all the six cycles of treatment was 2.9. Where the reason for stopping treatment was recorded on the EPR the most common cause for the cessation of treatment was because of the side effects caused by the treatment itself. Other causes were hospitalization with comorbidities, disease progression, or patient choice. Given the survival advantage of receiving the full course of all the six cycles of treatment, this should be administered if possible and the patients should be managed in such a way as to allow the complete treatment course to be given.

Validation of algorithms to detect distant metastases in men with prostate cancer using routine registry data in Denmark

Objective

Among patients with prostate cancer, diagnostic codes for bone metastases in the Danish National Registry of Patients have a sensitivity of 44%. In an attempt to improve the sensitivity of registry-based identification of metastases from prostate cancer, we tested a series of algorithms, combining elevated prostate-specific antigen (PSA) levels, use of antiresorptive therapy, and performed bone scintigraphy.

Patients and methods

We randomly selected 212 men diagnosed with prostate cancer in 2005–2010 in the Central Denmark Region with prespecified PSA values, antiresorptive therapy, and bone scintigraphy who did not have a registry-based diagnostic code indicating presence of distant metastases. We defined three candidate algorithms for bone metastases: 1) PSA >50 μg/L and bone scintigraphy, 2) PSA >50 μg/L and antiresorptive therapy, and 3) PSA ≤50 μg/L with antiresorptive therapy or bone scintigraphy. An algorithm for distant metastasis site other than bone was defined as PSA >50 μg/L alone. Medical chart review was used as the reference standard to establish the presence or absence of metastases. Validity was expressed as a positive predictive value (PPV) or a negative predictive value, based on whether the algorithms correctly classified metastases compared with the reference standard.

Results

We identified 113 men with evidence of metastases according to the candidate algorithms, and 99 men without evidence of metastases according to the candidate algorithm. The PPVs of PSA >50 μg/L were 0.10 (95% confidence interval [CI] 0.04–0.19) for bone metastases and 0.14 (95% CI 0.07–0.24) for nonbone metastases, regardless of receipt of antiresorptive therapy or presence of bone scintigraphy. The PPVs for any metastases were 0.16 (95% CI 0.06–0.32) for PSA >50 μg/L and 0.28 (95% CI 0.14–0.47) for PSA >50 μg/L with bone scintigraphy. Adding antiresorptive treatment to the algorithm did not improve PPV. All negative predictive values approached 1.00.

Conclusion

Algorithms based on elevated PSA, antiresorptive therapy, or bone scintigraphy are not suitable for supplementing diagnostic codes to identify additional cases of distant metastases among men with prostate cancer. However, it is possible that in this setting, medical chart review is not a gold standard to identify metastases.

Current Use of Imaging after Primary Treatment of Prostate Cancer

PURPOSE

Data are limited on imaging after primary treatment of localized prostate cancer.

MATERIALS AND METHODS

We identified 8,435 men newly diagnosed with nonmetastatic prostate cancer in 1995 to 2012 who were enrolled in CaPSURE™. Patients were followed after primary treatment with radical prostatectomy, cryosurgery, brachytherapy, external beam radiation therapy or androgen deprivation therapy. We assessed the use of bone scan, computerized tomography and magnetic resonance imaging after primary treatment. Factors associated with posttreatment outcomes (number of imaging tests, and time to first imaging and salvage treatment) were evaluated with multivariate Poisson regression and Cox proportional hazards regression.

RESULTS

The incidence of posttreatment bone scan, computerized tomography and magnetic resonance imaging was 20% or less. Last posttreatment log(prostate specific antigen) was associated with multiple posttreatment imaging. Management by radical prostatectomy, cryosurgery, external beam radiation therapy or brachytherapy vs androgen deprivation therapy was associated with a lower likelihood of posttreatment imaging. Of patients who were imaged after treatment 25% with radical prostatectomy and 9% with radiation underwent imaging before prostate specific antigen failure. The 5-year salvage treatment-free survival rate was 81%. Positive findings on posttreatment imaging were associated with a higher risk of salvage treatment.

CONCLUSIONS

Patients treated with androgen deprivation therapy for localized disease were most likely to be imaged, primarily by bone scan. Men treated with other therapies were less likely to be imaged and tended to undergo computerized tomography. Imaging may add value to posttreatment prostate specific antigen monitoring to identify disease recurrence and progression. Further studies are needed to establish guidelines for the optimal frequency and imaging type to monitor the treatment response.

Survival and clinical metastases among prostate cancer patients treated with androgen deprivation therapy in Sweden

OBJECTIVES

To examine the incidence of metastases and clinical course of prostate cancer patients who are without confirmed metastasis when initiating androgen deprivation therapy (ADT).

METHODS

Retrospective cohort study conducted using electronic medical records from Swedish outpatient urology clinics linked to national mandatory registries to capture medical and demographic data. Prostate cancer patients initiating ADT between 2000 and 2010 were followed from initiation of ADT to metastasis, death, and/or end of follow-up.

RESULTS

The 5-year cumulative incidence (CI) of metastasis was 18%. Survival was 60% after 5 years; results were similar for bone metastasis-free survival. The 5-year CI of castration-resistant prostate cancer (CRPC) was 50% and the median survival from CRPC development was 2.7 years. Serum prostate-specific antigen (PSA) levels and PSA doubling time were strong predictors of bone metastasis, any metastasis, and death.

CONCLUSION

This study provides understanding of the clinical course of prostate cancer patients without confirmed metastasis treated with ADT in Sweden. Greater PSA values and shorter PSA doubling time (particularly ≤ 6 months) were associated with increased risk of bone metastasis, any metastasis, and death.

Factors that predict the development of bone metastases due to prostate cancer: Recommendations for follow-up and therapeutic options

CONTEXT

Prostate cancer is a public health problem in Spain and in the Western world. Bone involvement, associated to significant morbidity, is practically constant in the advanced stages of the disease. This work aims to review the prognostic factors used in the usual clinical practice that predict the development of bone metastases and to analyze the follow-up and treatment option in these patient profiles.

ACQUIRING OF EVIDENCE

We performed a review of the literature on the useful factors in the context of therapy with intention to cure. We included the classical clinical values in the diagnosis (PSA, clinical stage, Gleason score on the biopsy) pathological factors (pT stage, margins, bladder invasion, tumor volume, lymph node involvement) and PSA kinetics in their different contexts and the histological and molecular parameters.

SYNTHESIS OF EVIDENCE

The tumor differentiation "Gleason" score and PSA are the most important predictive factors in the prediction of bone metastases in patients with intention to cure. Kinetic factors such as PSA doubling time (TDPSA) < 8 months or PSA > 10 ng/ml in the case of castration-resistant prostate cancer (CPRC), are predictive factors for the development of metastasis. Zoledronic acid and denosumab have demonstrated their effectiveness for the treatment of bone disease in randomized studies.

CONCLUSIONS

There are predictive factors within the usual clinical practice that make it possible to recognize the "patient at risk" to develop bone metastatic disease. The currently available treatments, zoledronic acid or denosumab, can help us in the management of the patient at risk of developing metastasis or metastatic patient, increasing the quality of life and decreasing skeletal events.

Aspirin improves outcome in high risk prostate cancer patients treated with radiation therapy

PURPOSE

High-risk prostate cancer (PC) has poor outcomes due to therapeutic resistance to conventional treatments, which include prostatectomy, radiation, and hormone therapy. Previous studies suggest that anticoagulant (AC) use may improve treatment outcomes in PC patients. We hypothesized that AC therapy confers a freedom from biochemical failure (FFBF) and overall survival (OS) benefit when administered with radiotherapy in patients with high-risk PC.

MATERIALS AND METHODS

Analysis was performed on 74 high-risk PC patients who were treated with radiotherapy from 2005 to 2008 at UT Southwestern. Of these patients, 43 were on AC including aspirin (95.6%), clopidogrel (17.8%), warfarin (20%), and multiple ACs (31.1%). Associations between AC use and FFBF, OS, distant metastasis, and toxicity were analyzed.

RESULTS

Median follow-up was 56.6 mo for all patients. For patients taking any AC compared with no AC, there was improved FFBF at 5 years of 80% vs. 62% (P = 0.003), and for aspirin the FFBF was 84% vs. 65% (P = 0.008). Aspirin use was also associated with reduced rates of distant metastases at 5 years (12.2% vs. 26.7%, P = 0.039). On subset analysis of patients with Gleason score (GS) 9-10 histology, aspirin resulted in improved 5-year OS (88% vs. 37%, P = 0.032), which remained significant on multivariable analysis (P<0.05).

CONCLUSIONS

AC use was associated with a FFBF benefit in high-risk PC which translated into an OS benefit in the highest risk PC patients with GS 9-10, who are most likely to experience mortality from PC. This hypothesis-generating result suggests AC use may represent an opportunity to augment current therapy.

Predicting the risk of bone metastasis in prostate cancer

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

Impact of Age at Diagnosis on Outcomes in Men with Castrate-Resistant Prostate Cancer (CRPC)

Background: The association between age and outcomes in men with castrate resistant prostate cancer (CRPC) is not well understood.

Objective: We aimed to evaluate CRPC patients to determine if their age at initial diagnosis impacted their cancer specific outcomes.

Design, Setting, and Participants: A retrospective chart review was conducted on 333 consecutive CRPC patients treated at the Princess Margaret Hospital (PMH) between 1995 and 2005. Patients were divided into 4 age categories, (A) <55, (B) 55-64, (C) 65-74 (reference), and (D) ≥ 75 years (yrs).

Outcome Measurements and Statistical Analysis: Primary endpoints included impact of age at diagnosis on overall survival (OS) and on prostate cancer specific survival. Secondary endpoints were time from diagnosis to development of CRPC, time from CRPC to death, and time from diagnosis to bone metastases.

Results and Limitations: The median OS from diagnosis to death was: Group A 5.5 yrs (95% CI 3.0-7.5); Group B 6.7 yrs (95% CI 5.9-8.4); Group C 7.8 yrs (95% CI 6.6-9.3); and Group D 4.3 years (95% CI 2.9-5.0). The hazard ratio (HR) for death in Group D was 2.58 (95% CI 1.58-4.21, p=0.0002); and in Group A was 1.49 (95% CI 0.90-2.46, p=0.13). The duration of hormone sensitivity in Group D was less and predictive of OS, as was Gleason Score ≥8 and Stage 4 disease at diagnosis.

Conclusions: Age at initial diagnosis appears to impact on outcome of patients who subsequently develop CRPC with a bimodal distribution of risk, with the shortest survivals in the ≥75 and <55 groups.

The relation between age and androgen deprivation therapy use among men in the Medicare population receiving radiation therapy for prostate cancer

OBJECTIVES

Neoadjuvant and concurrent androgen deprivation therapy (ncADT) is recommended for men with high-risk prostate cancer, but not low-risk cancer or short life expectancy. It is unclear whether the use of ncADT among older men in the community setting is aligned with the potential for clinical benefit.

MATERIALS AND METHODS

We used the Surveillance, Epidemiology, and End Results–Medicare database to assess patterns of ncADT use among men diagnosed with prostate cancer during 2004–2007 who received radiation therapy. Men were stratified according to tumor risk groups and life expectancy. We used logistic regression to identify factors associated with ncADT use within each risk group.

RESULTS

There were 10,686 men in the sample (mean age 74.2 years; 83.4% white). The use of ncADT was 80.7%, 54.1%, and 27.8% in the high-, intermediate-, and low-risk groups, respectively. Men with a life expectancy<5 years had higher rates of ncADT use than men with a life expectancy≥10 years in all risk groups. Within each risk group, advancing age was associated with higher likelihood of receiving ncADT (odds ratio for men aged 80–84 compared to 67–69=1.93 (95% CI 1.37–2.70); 1.51 (95% CI 1.22–1.87); and 1.71 (95% CI 1.14–2.57) for high-, intermediate-, and low-risk groups, respectively).

CONCLUSION

ncADT use is not consistent with guideline recommendations and is more frequent among men who are older, have shorter life expectancy, and are less likely to benefit from therapy.

Laminin receptor specific therapeutic gold nanoparticles (198AuNP-EGCg) show efficacy in treating prostate cancer

Systemic delivery of therapeutic agents to solid tumors is hindered by vascular and interstitial barriers. We hypothesized that prostate tumor specific epigallocatechin-gallate (EGCg) functionalized radioactive gold nanoparticles, when delivered intratumorally (IT), would circumvent transport barriers, resulting in targeted delivery of therapeutic payloads. The results described herein support our hypothesis. We report the development of inherently therapeutic gold nanoparticles derived from the Au-198 isotope; the range of the (198)Au β-particle (approximately 11 mm in tissue or approximately 1100 cell diameters) is sufficiently long to provide cross-fire effects of a radiation dose delivered to cells within the prostate gland and short enough to minimize the radiation dose to critical tissues near the periphery of the capsule. The formulation of biocompatible (198)AuNPs utilizes the redox chemistry of prostate tumor specific phytochemical EGCg as it converts gold salt into gold nanoparticles and also selectively binds with excellent affinity to Laminin67R receptors, which are over expressed in prostate tumor cells. Pharmacokinetic studies in PC-3 xenograft SCID mice showed approximately 72% retention of (198)AuNP-EGCg in tumors 24 h after intratumoral administration. Therapeutic studies showed 80% reduction of tumor volumes after 28 d demonstrating significant inhibition of tumor growth compared to controls. This innovative nanotechnological approach serves as a basis for designing biocompatible target specific antineoplastic agents. This novel intratumorally injectable (198)AuNP-EGCg nanotherapeutic agent may provide significant advances in oncology for use as an effective treatment for prostate and other solid tumors.

Clinical features and prognostic factors for patients with bone metastases from prostate cancer

To identify the clinical features and independent predictors of survival in patients with bone metastases from prostate cancer (PCa). We retrospectively analysed 115 PCa patients with bone metastases between 1997 and 2009. The overall survival rate after bone metastases was calculated using the Kaplan-Meier method. The prognostic factors were identified by univariate analysis using a log-rank test and by multivariate analysis using Cox proportional hazards regression models. The follow-up rate was 100%, the follow-up cases during 1, 3 and 5 years were 103, 79 and 55, respectively. The 1-, 3- and 5-year survival rates were 89.1%, 60.9% and 49.8%, respectively, with a median survival time of 48.5 months for patients with bone metastases from PCa. In univariate analysis, age, Gleason score, clinical stage, the number of bone lesions, alkaline phosphatase (ALP) level, invasion of neighbouring organs and non-regional lymph node metastases were correlated with prognosis. By multivariate analysis using Cox regression, ALP level, Gleason score and non-regional lymph node metastases were independent prognostic factors. These prognostic factors will help us to determine the appropriate dose and fraction of radiotherapy for these patients.

Mechanisms of cancer cell metastasis to the bone: a multistep process

For metastasis to occur, tumor cells must first detach from their tissue of origin. This requires altering both the tissue of origin and the cancer cell. Once detached, cancer cells in circulation must also acquire survival mechanisms. Although many may successfully disseminate, variation exists in the efficiency with which circulating tumor cells home to and invade the bone marrow as metastastic seeds. Disseminated tumor cells that do successfully invade the marrow are secured by cell-cell and cell-extracellular matrix adhesion. However, establishing a foothold in the marrow is not sufficient for disseminated tumor cells to create metastases. A significant latent phase must be overcome by either rescuing cellular proliferation or attenuating micrometastatic mass dormancy programs. Finally, growing metastases fuel osteolysis, osteoblastogenesis and T-cell differentiation, creating a variety of tumor phenotypes. Each step in the metastatic cascade is rich in biological targets and mechanistic pathways.

Characterising the castration-resistant prostate cancer population: a systematic review

BACKGROUND

Castration-resistant prostate cancer (CRPC) is an advanced form of prostate cancer associated with poor survival rates. However, characterisation of the disease epidemiology is hampered by use of varying terminology, definition and disease management. The aim of this review was to conduct a systematic review to provide greater clarity on the sum of the available epidemiologic evidence and to guide future research into the disease prevalence, progression, characteristics and outcome.

METHODS

Systematic searches of PubMed and Embase were performed in March 2010 to identify relevant observational studies relating to the epidemiology, progression and outcomes of CRPC. Further studies were identified for inclusion in our review through manual searches of the authors' bibliographical databases and the reference lists of the included articles.

RESULTS

We identified 12 articles (10 full papers and 2 abstracts) reporting studies that included a total of 71,179 patients observed for up to 12 years for evaluation in our review. Five studies looked at the prevalence of CRPC in patients with prostate cancer. Together, the data indicate that 10-20% of prostate cancer patients develop CRPC within approximately 5 years of follow-up. Two studies reported the prevalence of bone metastases present at diagnosis of CRPC. Together, ≥ 84% were shown to have metastases at diagnosis. Of those patients with no metastases present at diagnosis of CRPC, 33% could expect to develop them within 2 years. The median survival of patients with CRPC was reported in five studies, with values varying from 9 to 30 months. A pooled, sample-weighted survival estimate calculated from the survival data included in this review is 14 months. Very few studies that met our inclusion criteria evaluated treatment patterns in CRPC. One study reported that only 37% of patients with CRPC received chemotherapy, with the remainder receiving only steroids and supportive care. The most common palliative therapies administered to patients with skeletal symptoms were radiotherapy, radionuclide therapy, bisphosphonates and opioids.

CONCLUSIONS

This review highlights the poor prognosis of patients with CRPC, and demonstrates a survival of 9-13 months in those patients with metastatic CRPC. Furthermore, progression to CRPC is associated with deterioration in quality of life, and few therapeutic options are currently available to patients with CRPC. However, epidemiologic study of these patients is hampered by differing terminology, definitions and treatment paradigms. Our review highlights the need for further well-designed, epidemiological studies of CRPC, using standardised definitions and methods.