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New Molecular Tests Can Predict the Return of Prostate Cancer
New Molecular Tests Can Predict the Return of Prostate Cancer
Jason M. Alter, Ph.D.
Aureon Laboratories, Inc.
More than 234,000 men in the United States will be diagnosed with prostate cancer in 2006 and all these men will need to make treatment decisions and lifestyle changes. Although, diagnosis has improved due to screening advancements such as the PSA test, other aspects of diagnosis (such as Gleason grading by microscopic visualization and pathologist interpretation) remain the same as they have for many years. As men are diagnosed, their possibility for aggressive disease is assessed and they are grouped or are stratified into risk categories. Two new, exciting tests from Aureon Laboratories enable the prediction of prostate cancer recurrence at two points in the disease and treatment process: (1) after prostatectomy and (2) at the time of diagnosis.
A significant number of patients (15-40%) who have a prostatectomy will develop a serum PSA or biochemical recurrence (BCR). In addition, ~30% of men who have a PSA recurrence can still develop a metastasis some eight years post PSA/BCR suggesting that identifying this group of patients early in their treatment program is critical to their overall survival.
The current practice for following patients after a prostatectomy is to test their blood for prostate specific antigen (PSA) to determine whether their cancer is returning. This period can be a time of great anxiety and many patients are searching for additional sources of information in order to make a more-informed decision about possible treatment options.
An accurate prognosis is important because the majority of tumors are indolent and require minimal intervention while a subset are more aggressive and early intervention may be valuable. It is difficult for a pathologist to determine what will happen to the patient by pure visual inspection of the prostate cancer tumor. Two similar-looking tissue images could both be graded as a Gleason score of six (6) but one case could represent an indolent tumor while the other image could be that of a life threatening tumor.
Advancements in the fields of image analysis, mathematics, molecular markers and computer science have enabled the development of advanced, new tests incorporating new features that significantly improve the predictive power of prostate cancer post-diagnosis. These tests, available from Aureon Laboratories can predict disease recurrence and future disease severity at two points: (1) currently available, Prostate Pxô can predict disease recurrence after prostatectomy and (2) Prostate Px+ will predict disease recurrence/progression at the time of diagnosis using biopsy tissue: Prostate Px+ will be available early in 2007.
The Prostate Px test has two endpoints for cancer recurrence:
* PSA Recurrence Px Score describes the likelihood of the patient developing a PSA recurrence within five years of having their prostate removed.
* Disease Progression Px Score describes the likelihood of the patient developing Disease Progression defined as bone/soft tissue metastasis and/or androgen independent rise in PSA within five years of having their prostate removed.
Prostate Px benefits patients and physicians at a number of decision points after surgery. The predictive test is able to:
* Provide a probability of whether a patient, after a prostatectomy, will have a PSA recurrence within five years.
* Predict whether a patient, after a prostatectomy, will have disease progression within five years.
* Avoid possible side effects associated with therapy (e.g. androgen deprivation therapy) for asymptomatic low risk patients.
* Identify patients with high risk of clinical failure who may benefit from increased surveillance or early adjuvant, multi-modal therapy.
* Help relieve anxiety and allow patients, their families and their physicians to decide upon the best treatment regimen moving forward.
* Assist in patient selection for new therapies as part of randomized clinical trials.
At the Time of Diagnosis
In early 2007, Aureon will release Prostate Pxô+, a new predictive test for prostate cancer that will use biopsy tissue, at the time of diagnosis, and Aureonís system pathology platform to assess future disease severity and cancer recurrence.
Using biopsy specimens at the time of diagnosis, existing information is limited and interpretation is difficult (e.g., biopsy Gleason scores, PSA values, number of positive cores). Prostate Px+ will provide more objective, actionable data at the time of diagnosis to assist in selecting the most appropriate treatment plan. Specifically, Prostate Px+ should provide significant benefit in the following scenarios:
* For prostate cancer patients who appear to be at low risk at biopsy, Prostate Px+ will provide either valuable corroborating data or identify those occasional high-risk cases masking as low-risk patients.
* Many patients initially fall into an intermediate-risk categoryóProstate Px+ will provide enhanced discrimination to assist in identifying which patients are actually high-risk and which are low risk.
* A patientís potentially contradictory clinical/pathologic features will now be individually evaluated and identified using Prostate Px+.
* For those patients who appear to be at high risk upon biopsy, Prostate Px+ will help further characterize their level of risk.
The basis for the predictive power of Prostate Px and Prostate Px+ is Aureon Laboratoriesí unique breakthrough technology. Aureonís System Pathology platform combines histological, molecular and clinical information to predict cancer recurrence.
Depending upon which test is employed either biopsy or prostatectomy issue is sent from the pathology department at the hospital or the testing laboratory to Aureonís specialized laboratory. Aureonís approach integrates:
* Histology (tissue): analyzes the cells and other structures in a prostate cancer tissue sample. This results in the generation of specific (quantitative) features for inclusion in the mathematical model.
* Molecular markers: selectively measures specific proteins in prostate tissue samples in order to obtain a unique molecular picture of the patientís prostate cancer.
* Clinical data: takes into account clinical information such as the Gleason score and in the case of the post-prostatectomy test, pathology results from the patientís surgery.
By combining these sources of information and by applying advanced image analysis, computer technology and mathematics, the Prostate Px family of tests are able to provide patients a more thorough picture of their individual risk for recurrent disease.
Advanced Image Analysis
Image analysis is one of the key foundation technologies underlying Prostate Px and Prostate Px+ that uses a prostate tissue H&E image as input and outputs a variety of statistical measurements of histopathological objects presented in the image. Extracted features are combined with clinical and molecular information to predict disease recurrence in prostate cancer patients who have undergone radical prostatectomy.
Aureonís image analysis platform is the result of the latest technologies in image processing and analysis aided by significantly increased computational power. Most cancer image-analysis systems have been developed for cytological specimens and do not utilize the architectural information available at the tissue level.
Aureonís mathematics capability consists of a supervised multivariate analytic toolset capable of computing an optimized model to predict clinical outcomes using Support Vector Regression for censored data (SVRc). The fitness criterion used to assess models is a combination of three evaluation metrics: the Concordance Index (CI), sensitivity and specificity. The CI is defined as the probability that, of a pair of randomly chosen comparable patients, the patient with the higher score of the event of interest from the model will experience that event within a shorter time than does the other patient.
Biomarker Detection via Protein M-Plexô
Multiplexed in situ protein detection consists of strategies developed at Aureon to fluorescently tag individual antibodies and then selectively analyze each [antibody: antigen] complex with spectral imaging. Our automated high-throughput imaging system allows the separation of real signal from tissue auto-fluorescence, enabling a more sensitive and quantitative measurement of biomarkers. Furthermore, an elaborate quality control system has been implemented to guarantee day-to-day reproducibility.
High-dimensional information management software is utilized for clinical and specimen databases, as well as for accessioning and tracking all specimens and accompanying clinical data received at Aureon. The database includes patient clinical annotation, Hematoxylin and Eosin (H&E) image files and associated/result-oriented data sets from the laboratory activities including fluorescent and immunohistochemistry images, quantitative and qualitative pathology assessment,. All data files are linked to the primary tissue sample and the patient.
Aureonís new family of tests predicts prostate cancer recurrence and disease progression. These tests provide objective data needed to better determine individual patient risk and make decisions that are more informed. The benefits of both the Prostate Px and the new biopsy-based Prostate Px+ are clear given the need for additional, evidence-based information. The underlying foundation for the predictive power of these tests is Aureonís unique systems pathology technology, which integrates histological, molecular and clinical information to predict cancer recurrence.
Aureon Laboratories is dedicated to improving patient healthcare and advancing medicine by commercializing predictive tests for cancer recurrence. Until now, it has been very difficult to identify which patients fall into a high-risk category and which do not. Prostate Px tests can help relieve anxiety and assist both patients and their physicians in selecting the most appropriate treatment options.
More information on Prostate Px and Prostate Px+ is located at www.prostatepx.com or can be obtained via email by sending a request to ProstatePx@aureon.com or calling 1-914-377-4036.
About the Author: Jason Alter PhD