Dataset Information

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

ABSTRACT:

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.

SUBMITTER: Freedland SJ

PROVIDER: S-EPMC6986739 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Publications

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

Freedland Stephen J SJ Howard Lauren E LE Hanyok Brian T BT Kadiyala Vishnu K VK Kuang Jameson Y JY Whitney Colette A CA Wilks Floyd R FR Kane Christopher J CJ Terris Martha K MK Amling Christopher L CL Cooperberg Matthew R MR Aronson William J WJ Moreira Daniel M DM

BJU international 20160208 4

<h4>Objectives</h4>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.<h4>Patients and methods</h4>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 est ...[more]

PMID: 26762961

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Project description:Enzalutamide is a novel antiandrogen with proven efficacy in metastatic castration-resistant prostate cancer (mCRPC).To evaluate enzalutamide's effects on cancer and on androgens in blood and bone marrow, and associate these with clinical observations.In this prospective phase 2 study, 60 patients with bone mCRPC received enzalutamide 160mg orally daily and had transilial bone marrow biopsies before treatment and at 8 wk of treatment.Androgen signaling components (androgen receptor [AR], AR splice variant 7 (ARV7), v-ets avian erythroblastosis virus E26 oncogene homolog [ERG], cytochrome P450, family 17, subfamily A, polypeptide 1 [CYP17]) and molecules implicated in mCRPC progression (phospho-Met, phospho-Src, glucocorticoid receptor, Ki67) were assessed by immunohistochemistry; testosterone, cortisol, and androstenedione concentrations were assessed by liquid chromatography-tandem mass spectrometry; AR copy number was assessed by real-time polymerase chain reaction. Descriptive statistics were applied.Median time to treatment discontinuation was 22 wk (95% confidence interval, 19.9-29.6). Twenty-two (37%) patients exhibited primary resistance to enzalutamide, discontinuing treatment within 4 mo. Maximal prostate-specific antigen (PSA) decline ? 50% and ? 90% occurred in 27 (45%) and 13 (22%) patients, respectively. Following 8 wk of treatment, bone marrow and circulating testosterone levels increased. Pretreatment tumor nuclear AR overexpression (> 75%) and CYP17 (> 10%) expression were associated with benefit (p = 0.018). AR subcellular localization shift from the nucleus was confirmed in eight paired samples (with PSA decline) of 23 evaluable paired samples. Presence of an ARV7 variant was associated with primary resistance to enzalutamide (p = 0.018). Limited patient numbers warrant further validation.The observed subcellular shift of AR from the nucleus and increased testosterone concentration provide the first evidence in humans that enzalutamide suppresses AR signaling while inducing an adaptive feedback. Persistent androgen signaling in mCRPC was predictive of benefit and ARV7 was associated with primary resistance.We report a first bone biopsy study in metastatic prostate cancer in humans that searched for predictors of outcome of enzalutamide therapy. Benefit is linked to a pretreatment androgen-signaling signature.ClinicalTrials.gov identifier NCT01091103.

Project description:BackgroundRecent approvals of second-generation androgen receptor inhibitors (SGARIs) have changed the treatment landscape for non-metastatic castration-resistant prostate cancer (nmCRPC). These SGARIs have similar efficacy but differ in safety profiles. We used a discrete choice experiment to explore how United States physicians make treatment decisions between adverse events (AEs) and survival gains in nmCRPC, a largely asymptomatic disease.MethodsTreating physicians (n = 149) participated in an online survey that included 14 treatment choice questions, each comparing 2 hypothetical treatment profiles, which varied in terms of 5 safety and 2 efficacy attributes. We described safety attributes (fatigue, skin rash, cognitive problems, falls, and fractures) in terms of severity and frequency, and efficacy attributes (overall survival [OS] and time to pain progression) in terms of duration of effect. We used a random parameters logit model to estimate preference weights and importance scores for each attribute. We also estimated the amount of survival gain physicians were willing to trade for a reduction in specific AEs between treatment options.ResultsPhysicians placed more importance on survival than on time to pain progression, and viewed a reduction in cognitive problems from severe to none, a reduction in risk of a serious fracture from 8% to none, and a reduction in fatigue from severe to none as the most important safety attributes. Physicians were willing to forego 9.1 and 6.6 months of OS, respectively, to reduce cognitive problems and fatigue from severe to mild-to-moderate. To reduce the risk of a serious fracture from 8 to 5% and 5% to none, physicians were willing to trade 3.9 and 5.3 months of OS, respectively.ConclusionsPhysicians were willing to trade substantial amounts of survival to avoid AEs between hypothetical treatments. These results emphasize the importance of carefully balancing therapies' benefits and risks to ultimately optimize the overall quality of nmCRPC patients' survival. Nonetheless, it is noted that the results from the study sample of 149 physicans may not be representative of the viewpoints of all nmCRPC-treating physicians.

Dataset Information

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

Objectives

Patients and methods

Results

Conclusion

Publications

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

Similar Datasets

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