The good news is more breast cancers are caught early because of the technological advancement of diagnostic tools
being used during the screening process. The not-so-good news is once they find cancer, they cannot accurately tell if
it will spread. Therefore, cancer treatments might be inappropriate and unnecessary for the cancer being treated. The
goal is to create tests that will determine the most
effective course of treatment for the cancer diagnosed.Target Discovery scientists will be working with University of Texas M. D. Anderson Cancer Center researchers to develop a new generation of cancer diagnostic tools that go beyond simple detection to determining which of the cancers found are invasive cancers.
According to Target Diagnostics, the body modifies its proteins to create many isoforms that control biological activity. These modifications can go awry, making isoforms the best indicators of the type and severity of many diseases like cancer. M. D. Anderson Cancer Center researchers will provide the company with breast cancer samples, and the scientists will use a technology they developed, called Isotope-Differentiated Binding Energy Shift Tags, to find protein biomarkers. This information will lead to the development of diagnostic tests that can tell the difference between invasive and non-invasive forms of breast cancer. Once this goal is reached, they hope to do this for other cancers as well.
1. The goal is to create tests that will determine the most effective course of treatment for a cancer diagnosed. So they develop a test to find protein biomarkers.
However, none of the available laboratory tests used in the selection of treatments for cancer patients have ever been tested for 'efficacy'. This includes estrogen receptor, progesterone receptor, Her2/neu, immunohistochemical staining for tumor classification, bacterial culture and sensitivity testing, cell culture assay tests, CT, MRI and FDG Pet Scans to measure tumor response to treatment.
The only data supporting any of them relate to test 'accuracy', and there is a total lack of information regarding test 'efficacy' (randomized trials with outcome measurements for diagnostic tests). There is no literature establishing clinical 'efficacy' of these laboratory tests, because they will not likely ever be subjected to such an unreasonably high bar criterion for clinical use.
So, will the American Society of Clinical Oncology (ASCO) or anyone else seriously propose that any of the molecular tests now available (Oncotype DX, EGFR amplification/mutation), or ones being worked on by Target Diagnostics/MD Anderson, should have to be proven 'efficacious', as opposed to merely 'accurate', before they are used in clinical decisions regarding treatment selection?
The established criterion on which to judge all laboratory tests used to help in the selection of cancer treatment has always been the predictive 'accuracy' of the test and not test 'efficacy'.
In virtually all forms of cancer, clinical trials have failed to identify best drug regimens for use in all individuals with a given form of cancer. In light of the precious little in the way of guidance from clinical trials with respect to best empiric therapy and the importance of basing cancer treatment at least in part on patient preferences, it is entirely reasonable to support judicious application of laboratory tests which have been well characterized with respect to test 'accuracy'.
These diagnostic tests should be held to that criteria, and not to that of therapy. These laboratory tests are a tool for the oncologist. The oncologist should take advantage of all the tools available to him/her to treat a patient. And since studies show that only 25-40% of patients do respond to chemotherapy that is abailable to them, there should be due consideration for these tests to the resistance that has been found to chemotherapy drugs.
Posted at 12:36PM on Apr 21st 2006 by Gregory D. Pawelski