MedicalResearch.com Interview with:
Mohummad Minhaj Siddiqui, MD
Assistant Professor of Surgery - Urology
Director of Urologic Robotic Surgery
University of Maryland School of Medicine and
Peter A. Pinto, M.DHead, Prostate Cancer Section Director, Fellowship Program
Urologic Oncology Branch National Cancer Institute National Institutes of Health Bethesda, Maryland Medical Research: What is the background for this study? What are the main findings?
Response: For men suspected of having prostate cancer due to an elevated PSA or abnormal digital rectal exam, the next step in their diagnostic workup has traditionally been a standard 12-core biopsy to evenly sample the entire gland. Unlike most other cancers, prostate cancer is one of the few solid tumors left which is diagnosed by randomly sampling the gland with the hope of biopsying the tumor, if it is present. This paradigm has been largely due to the fact that imaging to date has been limited in its ability to identify prostate cancer. Recent advancements in multiparametric MRI of the prostate however has significantly improved clinician's ability to identify regions in the prostate suspicious for cancer. This has led to the emergence of MR/Ultrasound fusion technology which allows for targeted biopsy of the prostate into regions suspicious for cancer.
Although conceptually, it makes sense that a targeted biopsy has the potential to perform better than the standard random sampling of the prostate in the diagnosis of prostate cancer, studies were needed to understand if this is true, and if so, if the improvement was substantial enough to justify the extra expense and effort needed to obtain a MRI guided biopsy. This study performed at the National Cancer Institute's Clinical Center sought to address this clinical question of interest. From 2007-2014, a total of 1003 men suspected to have prostate cancer underwent an MRI of the prostate. If an area of suspicion was seen in the prostate, these men underwent both the targeted biopsy of the suspicious region in the prostate as well as the standard 12-core needle biopsy during the same session. The results from the targeted biopsy were compared to the results of the standard biopsy.
The key findings in this study was that targeted biopsy improved the rate at which high-risk clinically significant cancer was diagnosed by 30%. Of interest, the study also found that low-risk, clinically insignificant disease (the type of prostate cancer that is unlikely to cause any harm to the patient over the course of his natural life) was decreased in diagnosis by 17%. Decrease of diagnosis of such disease has the potential benefit that it could lead to less over-treatment of cancer that never needed to be treated. In a subset of 170 men that ultimately underwent surgery to remove the prostate to treat their cancer, we were further able to examine how well the prostate biopsy reflected the actual cancer burden in the whole gland. It is well known that standard biopsy can actually underestimate the total cancer grade in the whole prostate in upwards of 30-40% of cases. We found that the targeted biopsy was significantly better at predicting whether the patient had intermediate to high-risk cancer compared to standard biopsy. Through further analysis using a statistical method called decision curve analysis, we further found that for men who wish to undergo surgery for intermediate to high-risk cancer, but wish to go on active surveillance for low-risk cancer, targeted biopsy led to better decision making compared to standard biopsy, or even the two techniques combined.
MedicalResearch.com Interview with:
Mufaddal Mamawala, MBBS, MPH, CPH
Biostatistician Johns Hopkins School of Medicine
Brady Urological Institute
Medical Research: What is the background for this study? What are the main findings?
Dr. Mamawala: Twenty years after prostate-specific antigen (PSA) was FDA approved for the diagnosis of prostate cancer, its use remains highly controversial. There has been an ‘over- diagnosis’ and ‘over-treatment’ of low-risk prostate cancers that would have never progressed to a more lethal form of the disease during one’s life. Active surveillance (AS) is an alternative to immediate treatment, which allows for monitoring of favorable risk patients with selective delayed intervention among those with disease progression. However ‘misclassification’ is a cause of concern for patients in the initial years of been in AS. The initial biopsy may have missed an area of prostate with an aggressive cancer, due to under-sampling of cores or due to randomness, such that this patient could get misclassified as having a low-risk disease and by the time the follow-up biopsy shows an aggressive cancer the window of curability is lost.
However with more sampling of the prostate there is more likelihood to find an aggressive cancer. As such if the patient is compliant with their biopsies, and more prostate is sampled under the microscope, better are the chances of finding a higher risk cancer. Conversely if the patient has more biopsies that show no high-risk cancer then they are less likely to have a high-risk cancer on future biopsies. Thus we wanted to evaluate the risk of reclassification, from a low-risk disease to a high-risk disease (higher Gleason score, or increase in extent of the disease), over a period of time in compliant active surveillance patients. The length of time under Active surveillance without reclassification has not been evaluated as a predictor of future reclassification. Biopsies are invasive procedures, and the fact that patient has to undergo this invasive procedure regularly is a deterrent from been in Active surveillance. This study would help to make informed decisions about the need for doing frequent biopsies in light with other clinical factors especially in older patients who had many non-reclassifying biopsies before.
We found that the risk of reclassification was not equally distributed across time. As a result of ‘under sampling’ of prostate at diagnostic biopsy we had highest rates of reclassification in the first two years of been in Active surveillance with more than 50% of total reclassifications happening during those two years. The ‘low-risk’ and the ‘very-low-risk’ groups, determined by the Epstein criteria, had similar rates of reclassification in the first two years. After first two years the ‘low-risk’ group were 2.4 times as likely to have a higher risk of reclassification than the ‘very-low-risk’ group. In both the groups the risk of reclassification declined over time significantly by at least 30% with each biopsy that did not show reclassification.
MedicalResearch.com Interview with:
Dr. Robert S. DiPaola
Director, Rutgers Cancer Institute of New Jersey
New Brunswick, NJ 08901
Medical Research: What is the background for this study? What are the main findings?
Dr. DiPaola: Despite significant recent improvements in the treatment of advanced castration-resistant prostate cancer, there remains a need for a standard therapy for those patients who have an early relapse with PSA progression after local therapy. Immune therapy with poxvirus vaccines are optimal, because they can induce potent immune responses by mimicking natural infection, have great flexibility regarding antigen composition and are easily administered.
ECOG-ACRIN Cancer Research Group investigators conducted a Phase II clinical trial examining adult patients from member institutions with advanced prostate cancer (as evidenced by two rising prostate-specific antigen or PSA values and no visible metastasis) who had prior surgery or radiation. We explored two different experimental treatment options.
In step one, patients were treated with PROSTVAC-V/TRICOM and PROSTVAC-F/TRICOM. PROSTVAC-V is derived from a vaccinia virus that was used for many years to vaccinate against smallpox. This virus is modified to produce a PSA protein that helps focus the body’s immune response to the PSA in the prostate tumor. In addition, it is modified to produce three other proteins that help increase an immune cell’s ability to destroy its target (TRICOM). PROSTVAC-F is made from the fowlpox virus, which is found in birds and not known to cause any human disease. It contains the same genetic material as PROSTAC-V, but is given multiple times to further boost the body’s immune system.
Patients in the study were given one cycle of PROSTVAC-V/TRICOM followed by PROSTVAC-F/TRICOM for subsequent cycles in combination with a drug known as GM-CSF. GM-CSF is a protein normally made by the body to increase the amount of certain white blood cells and make them more active. When in drug form, it is used to boost the body’s immune system to fight off disease. After six months from first treatment, 25 of 40 eligible patients (63 percent) were found to have no disease progression and experienced minimal toxicity. The rate of rise of PSA also decreased. The second part of the study included the addition of hormone therapy (androgen ablation) to the PROSTVAC-VF/TRICOM combination. In the 27 patients eligible for this step, 20 patients (74 percent) experienced a significant response at seven months.
MedicalResearch.com Interview with:David R. Ziehr B.S., MD Candidate
Harvard Medical School
Medical Research: What is the background for this study? What are the main findings?Response: Androgen deprivation therapy (ADT), commonly achieved with gonadotropin-releasing hormone agonists or antagonists, is a mainstay of prostate cancer therapy. While randomized controlled trials demonstrate that ADT improves survival among men with unfavorable risk prostate cancer, retrospective studies have suggested that some men with comorbid illnesses such as heart disease may not derive a benefit from—or may even be harmed by—ADT. However, the nature of this harm has not been characterized. We studied over 5000 men with prostate cancer who were treated with brachytherapy (implanted radioactive seeds) with or without ADT. We analyzed the men based on pre-treatment cardiac comorbidity and examined the association between ADT and death from cardiac causes. We found that among men with congestive heart failure or a past myocardial infarction (MI), Androgen deprivation therapy was associated with a three-times greater risk of death from heart disease. However, Androgen deprivation therapy was not associated with greater risk of cardiac mortality in men without heart disease or with a risk factor for heart disease, such as diabetes, hypertension or hyperlipidemia.
MedicalResearch.com Interview with: Emma H. Allott PhD
Division of Urology, Department of Surgery, Duke University School of Medicine
Cancer Prevention, Detection, and Control Program, Duke Cancer Institute Division of Urology
Veterans Affairs Medical Center Durham Durham, North Carolina.
Medical Research: What are the main findings of the study?Dr. Allott: Relative to normal triglyceride levels, high triglycerides (≥150 mg/dl) were associated with 35% increased risk of prostate cancer recurrence. In addition, we found that each 10 mg/dl increase in total serum cholesterol above the abnormal cut-off value of 200 mg/dl was associated with a 9% increased risk of prostate cancer recurrence, while each 10 mg/dl increase in HDL (high density lipoprotein; “good” cholesterol) below the abnormal cut-off value of 40 mg/dl was associated with a 39% increased risk of prostate cancer recurrence. These findings suggest that normalization, or even partial normalization, of serum lipid levels among men with dyslipidemia may reduce the risk of prostate cancer recurrence.
MedicalResearch.com Interview with: Maarten C. Bosland, DVSc, PhD
Professor of Pathology
Department of Pathology, College of Medicine
University of Illinois at Chicago
Chicago, IL 60612
Medical Research: What are the main findings of the study?Dr. Bosland:The two main findings are :
(1) that long-term, low-dose testosterone treatment induces prostate cancer in rats (none occurred in control rats) and increases the number of rats with malignant tumors at any site in the body compared to control rats, and
(2) that in rats treated long-term with testosterone after a single prostate-targeted chemical carcinogen treatment a high incidence of prostate cancer is induced, even at a very low testosterone dose. (more…)
MedicalResearch.com Interview with:Dr. Jyotsna Batra
QUT Institute of Health and Biomedical Innovation's
Queensland University of Technology
Medical Research: What are the main findings of the study?Dr Batra: Prostate cancer is a disease with upto 40% genetic component. Previous Genome-wide association studies have identified 77 risk loci associated with prostate cancer. This study is further extension of previous GWASs and also involved meta-analysis of multi-ethnic populations. Through this large study involving approximately 90,0000 individuals, 23 new susceptibility loci were identified to be associated with prostate cancer, 15 variants were identified among men of European ancestry, 7 were identified in multi-ancestry analyses and 1 was associated with early-onset prostate cancer.
MedicalResearch.com Interview with: Vanessa Er PhD
School of Social and Community Medicine
University of Bristol and Bristol Nutrition BRU
Medical Research: What are the main findings of the study?Dr. Er: We found that men who had optimal intake of three nutrients- calcium, selenium and foods rich in lycopene- had a lower risk of prostate cancer. Mainly, men who ate over 10 servings/week of tomatoes and tomato-based products had 18% reduction in risk of developing prostate cancer. We also found that the risk of prostate cancer was lower in men who had high intake of fruits and vegetables.
MedicalResearch.com Interview with: Audrey J. Gaskins, Sc.D.
Postdoctoral Research Fellow
Department of Nutrition
Harvard School of Public Health
Medical Research: What are the main findings of the study?Answers: In our large prospective cohort study, we found that higher adherence to several healthy dietary patterns (e.g. the Alternate Healthy Eating Index 2010, Alternate Mediterranean Diet, and Fertility Diet) prior to pregnancy was not associated with risk of pregnancy loss.
MedicalResearch.com Interview with:Isaac J. Powell MD
Wayne State University/Karmanos Cancer Inst
University Health Center
Detroit, MI 48201.
Medical Research: What is the background for your study?Dr. Powell: During the PSA testing era for prostate cancer, which is responsible for early treatment, survival disparity between African Americans and European Americans has been eliminated.
MedicalResearch.com Interview with: Tomasz M. Beer, M.D. FACP
OHSU Knight Cancer Institute
Oregon Health and Science University
Medical Research: What are the main findings of the study?Dr. Beer: In the study, we found that compared to placebo, enzalutamide improves overall survival, progression-free survival, quality of life, and delays the need for chemotherapy. Enzalutamide is superior to placebo with respect to all planned endpoints, across all subsets of the patient population in the study. Enzalutamide treatment is associated with an excellent safety profile.
MedicalResearch.com Interview with:Grace Lu-Yao PhD, MPH
Professor of Medicine
Robert Wood Johnson Medical School
Rutgers, The State University of New Jersey
Rutgers Cancer Institute of New Jersey
New Brunswick, NJ 08903-2681
Medical Research: What are the main findings of the study?Dr. Lu-Yao:Primary ADT (ie., use of androgen deprivation as an alternative to surgery, radiation or conservative management for the initial management of prostate cancer) is not associated with improved overall or disease specific survival.
MedicalResearch.com with:Sandip M. Prasad MD
Medical University of South Carolina, Charleston, SC and
Scott E. Eggener, MD
Associate Professor of Surgery
Co-Director, Prostate Cancer Program
Director of Translational and Outcomes Research, Section of Urology
University of Chicago Medical Center, Chicago, IL;
Medical Research: What are the main findings of the study?Answer: Depressed men with a diagnosis of intermediate- or high-risk prostate cancer have worse overall outcomes than those without baseline depression and are less likely to undergo definitive therapy. The difference in overall survival between men with and without a depression diagnosis was independent of prostate cancer treatment type.
MedicalResearch.com Interview with:
Katharine N. Sourbeer, BS
Institute for Medical Research
MedicalResearch: What are the main findings of the study?Answer: In a study where biopsies were conducted independent from PSA, more metabolic syndrome components were found to be associated with more high-grade prostate cancers. (more…)
MedicalResearch.com Interview with:Edward Giovannucci, MD, ScD
Department of Nutrition
Harvard School of Public Health
MedicalResearch: What are the main findings of the study?Dr. Giovannucci: In 50,000 men followed over 24 years, we found that those regularly consuming tomato products, which are high in lycopene, had a 30% lower risk of developing lethal prostate cancer. Among men being screened regularly with PSA, the risk reduction from high tomato consumption was 50%. We also examined the prostate cancer tissue and found that higher dietary lycopene intake was associated with less new blood vessel formation, which may help explain why the cancers were less likely to progress.
MedicalResearch.com Interview with: Adriana C. Vidal, Ph. D.
Department of Obstetrics & Gynecology
Division of Clinical & Epidemiologic Research and
Cancer Prevention, Detection and Control Research Program and Department of Surgery Division of Urology
Duke University School of Medicine Durham, NC 27710
MedicalResearch: What are the main findings of the study?Dr. Vidal: Among 430 veterans at the VA Hospital in Durham, N.C., including 156 men with confirmed prostate cancer, we found that men who self-reported a higher intake of carbohydrates were at a reduced risk of both low-grade and high-grade prostate cancer.
Moreover, we found that intake of foods with high glycemic index increased total prostate cancer risk in black men. However, a higher fiber intake was associated with reduced risk of high grade prostate cancer.
MedicalResearch.com Interview with: Dr. Ignacio F. San Francisco
Departamento de Urología, Facultad de Medicina,
Pontificia Universidad Católica de Chile, Santiago, Chile
MedicalResearch: What are the main findings of the study?Answer: Increasingly, men with low-risk prostate cancer are undergoing a close monitoring regimen called active surveillance, instead of moving forward immediately with treatment. However it is still unclear which men will develop evidence for worsening or more aggressive disease during active surveillance. In this study of 154 men with Gleason 6 prostate cancer followed for 38 months, we found that low levels of free testosterone were significantly associated with increased risk of developing more aggressive disease. We found no significant association with total testosterone concentrations, although there was a general trend towards increased risk with lower levels.
MedicalResearch.com Interview with:Arturo Araujo, PhD IMO
Moffitt Cancer Center
Tampa, FL 33612
MedicalResearch: What are the main findings of the study?Dr. Araujo: Using in vivo approaches it is often challenging to study the multiple simultaneous interactions occurring at various time points in the setting of bone metastasis. However, integrating biological data with a powerful computational model allowed us to build a tool that could not only mimic the in vivo growth of cancer in bone but also to determine how the disease was behaving at any given time point. The key finding for us was that the computational model demonstrated the phasic or cyclical nature of how the prostate cancers grow in bone. For example, a wave of osteoclast mediated bone resorption would be followed by sustained bone formation by osteoblasts, followed again by bone reposition. We think these findings could provide novel insights into when the best time to apply therapies might be in order to obtain maximum efficiency.
MedicalResearch.com Interview with:Alice Dragomir, MSc, PhD
Urology/Surgery, McGill University
MedicalResearch.com: What are the main findings of the study?Authors’ response: Our study demonstrates that for eligible patients, active surveillance could offer not only the known clinical advantages from the patient’s perspective, but also economic benefits from the health care system’s perspective. At the national level, the cost savings of an annual cohort of incident prostate cancers managed with active surveillance over a first year and 5 years of follow-up could be substantial. These are estimated at $96 million.
MedicalResearch.com Interview with:Angelo M. De Marzo MD PhD
Professor of Pathology
Johns Hopkins School of Medicine
Baltimore, MD 21231
MedicalResearch.com: What are the main findings of the study?Dr. De Marzo: Working as a team with Dr. Elizabeth Platz and a group of other investigators we found that men with chronic inflammation in their benign areas of their prostate biopsies had a higher chance of prostate cancer, and especially higher grade cancers, which are associated with disease aggressiveness. A key unique aspect of the study is that the samples were taken from man who were enrolled in the Prostate Cancer Prevention Trial (PCPT), a trial in which all men entering the study had a relatively low PSA, and, all men at the end of study who did not already have a diagnosis of prostate cancer were offered a prostate biopsy regardless of their PSA. This study design, unlike a standard association study, allowed us to minimize the potential bias whereby inflammation is associated itself with elevations in PSA. In this standard design approach, when cancer is detected it could artifactually appear that inflammation is associated with cancer because the inflammation was in part driving the PSA elevation, which prompted the biopsy in which cancer was detected.
MedicalResearch.com Interview with:Dr. Thomas M. Pisansky MD
Mayo Clinic, Rochester, Minnesota
MedicalResearch.com: What are the main findings of the study?Dr. Pisansky:This patient-reported outcomes research did not identify a beneficial effect of once-daily tadalafil to prevent radiotherapy-related erectile dysfunction in men with prostate cancer.
MedicalResearch.com Interview with: Florence K. Keane, MD
Harvard Radiation Oncology Program, Harvard Medical School
and Anthony V. D’Amico, MD, PhD
Department of Radiation Oncology,
Dana Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts
MedicalResearch.com: What are the main findings of the study:Answer: Patients with unfavorable intermediate-risk prostate cancer (PC)  have an increased risk of PC-specific mortality (PCSM) after radiotherapy (RT) with or without androgen suppression therapy (AST) compared to favorable intermediate-risk patients [2,3]. We provided validation for this prognostic subdivision using mature data with a median follow-up of 14.3 years from a prospective randomized trial comparing RT alone with RT and 6 months of AST . We also assessed the risk of PCSM in patients with unfavorable intermediate-risk PC compared with high-risk prostate cancer.
Our main findings were as follows.
First, there were no prostate cancer deaths observed in favorable intermediate-risk patients, despite 50% receiving RT alone.
Second, there was not a statistically significant difference in the risk of PCSM in men with unfavorable intermediate-risk prostate cancer compared to men with high-risk PC after randomizing for age, comorbidities and treatment arm. While it is possible that a difference may emerge with longer follow-up, these results suggest that some men with unfavorable intermediate-risk PC may harbor occult GS 8-10 disease and could benefit from a 3.0-Tesla multiparametric MRI and targeted biopsy to rule out GS 8-10 disease.
MedicalResearch.com Interview with:Dr. Maarten de Rooij MD, PhD Candidate
Department of Radiology
Radboud University Nijmegen Medical Centre
Nijmegen, Gelderland 6525 GA, The Netherlands
MedicalResearch.com: What are the main findings of the study?Dr. de Rooij : Prostate cancer is the most common cancer in men and the second leading cause of cancer related death. The current diagnosis is based on ‘random or blind’ systematic transrectal ultrasound guided prostate biopsies in men with an elevated PSA. This can lead to over-diagnosis and over-treatment of prostate cancer, but can also miss important tumors. The role of multiparametric MRI (mpMRI) to improve the diagnosis of prostate cancer is evolving. In this meta-analysis we determined the diagnostic accuracy of mpMRI for the detection of prostate cancer. Our analysis included 7 studies using mpMRI which showed high overall specificity (0.88; 95% CI 0.82-0.92), with variable but high negative predictive values (0.65 - 0.95) and sensitivities (0.74; 95% CI 0.66-0.81).
MedicalResearch.com Interview with: Primo N. Lara, Jr, MD,
Professor of Medicine, University of California Davis School of Medicine
Associate Director for Translational Research
UC Davis Comprehensive Cancer Center
Sacramento, CA 95817
MedicalResearch.com: What are the main findings of the study:Dr. Lara: “We found that blood markers of bone turnover can be used to predict outcomes in men with advanced prostate cancer with spread to bone. We also found that a small proportion of men could be predicted to benefit from an investigational drug based on these same markers.”
MedicalResearch.com Interview with:David M. Albala, MD
Associated Medical Professionals of NY, PLLC
Syracuse, NY 13210
MedicalResearch.com: What are the main findings of the study?Dr. Albala: Prostate cancer is the second leading cause of cancer death and American man. Prostate cancer diagnosis and mortality differences between African American and Caucasian populations have been highlighted in the literature. Research has shown that African American males are at a biological predisposition for prostate cancer and that additional socioeconomic and physician-patient educational factors may contribute to a higher mortality rate among this group - over two times greater than that of Caucasian American males.
At present the most commonly used to detection tools for prostate cancer are the serum prostatic specific antigen test (PSA) and a digital rectal examination (DRE). These complementary tests provide physicians with an indication of whether to proceed with biopsy for a definitive pathological diagnosis. Despite ongoing disputes regarding the effectiveness of PSA screening as an indicator for prostate cancer, a superior alternative test as yet to become available for men at risk.
The American Urological Association (AUA) emphasizes the value of early detection and that sheared decision-making should not be overlooked and that shared decision making should be integral to screening decisions. The AUA urges individuals to personally assess, with their physicians, whether a PSA screen is necessary. Emphasis should be placed on the proper education of African American men who are at increased risk for the disease, as well as on their participation in repeated screening practices for the earliest possible detection of prostate cancer.
MedicalResearch.com Interview with:Dr David P. Turner PhD
Assistant Professor, Director of shRNA Technology
Medical University of South Carolina
Dept of Pathology & Lab Medicine
Charleston SC 29425
MedicalResearch.com: What are the main findings of the study?Dr. Turner: Our research has identified a potential mechanistic link between sugar derived metabolites and cancer associated pathways which may be a biological consequence of the socioeconomic and biological factors that are known to drive cancer health disparity. African Americans develop and die more frequently of cancer than any other population in the US. We examined the levels of reactive metabolites known as advanced glycation end-products, or AGEs for short, in serum and tumor samples from African American and Non-Hispanic White prostate cancer patients. In both the serum and tumor tissue, the levels of AGE metabolites were consistently higher in the African American prostate cancer patients than their White counterparts. AGE functions as a ligand for the receptor for AGEs, or RAGE for short. We also identified that RAGE protein levels were higher in African Americans with prostate cancer.
MedicalResearch.com Interview with:Dr. Laurent Azoulay
Project Leader, Lady Davis Institute
Assistant Professor, Department of Oncology, McGill University
MedicalResearch.com: What are the main findings of the study?Dr. Azoulay:Using large population-based databases from the UK, we assembled a cohort of men newly-diagnosed with non-metastatic prostate cancer. Within this group of men, the use of statins after prostate cancer diagnosis was associated with a 24% decreased risk in cancer-related mortality. We observed duration- as well as a dose-response relationships. Furthermore, in a secondary analysis, we observed that the benefits were greater among men who used also used statins before their diagnosis, with more modest yet significant benefits among men who initiated the treatment after their diagnosis. The latter result is one of the novelties of this study, as it provides an estimate of the potential benefits of statins, if used in the adjuvant setting.
MedicalResearch.com Interview with:Reina Haque, PhD, MPH
Research scientist, Kaiser Permanente Department of Research & Evaluation
MedicalResearch.com: What are the main findings of the study?Answer:The main study findings are that men who are overweight or obese when they are diagnosed with prostate cancer are more likely to die from the disease than men who are of healthy weight. In patients with more aggressive forms of prostate cancer, the researchers also found an even stronger correlation between obesity and mortality.
The study was restricted to patients undergoing surgical treatment for prostate cancer, rather than other treatments such as radiation or hormone therapy.
MedicalResearch.com Interview withSusan Halabi, PhD
Duke University Medical Center
Durham, NC 27710
MedicalResearch.com: What are the main findings of the study?Dr. Halabi: The purpose of assessing surrogate endpoints is to allow for a more rapid and efficient determination of whether a given therapy provides clinical benefit to patients by prolonging their life.
We sought to evaluate PSA kinetics as surrogate endpoints for overall survival (OS) in mCRPC patients who were receiving second line chemotherapy (cabazitaxel or mitoxantrone) following progression after docetaxel. Using different analytical approaches, we found that PSA declines within the first three months of treatment are not appropriate as surrogate markers of clinical benefit in men who were receiving second line chemotherapy.
This analysis has important clinical care and study design implications: it has become common to use ≥30% decline in PSA as a clinical trial endpoint for all patients with metastatic CRPC, based on the original front-line docetaxel data. The data presented in this study suggest that this is erroneous. Further we believe these data are important because they demonstrate that there are different disease states within the group of patients with “metastatic CRPC". To make the assumption that the same surrogate endpoint can be used across the board may seem like an obvious mistake, but permeates the literature. (more…)
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