The Journal of the American Medical Association (JAMA), Vol. 301, No.7, has published positive results from a major prospective 5-year multicenter study of over 400 enrolled patients demonstrating that guanylyl cyclase C (GCC) is the strongest independent predictor of colorectal cancer recurrence in patients considered low risk by current assessment methods.
The study was conducted by investigators from Thomas Jefferson University, with contributions from McGill University, the Fox Chase Cancer Center and others. DiagnoCure Inc. owns the exclusive worldwide diagnostic rights to the GCC biomarker, and since last September has offered the PrevistageTM GCC test to physicians and patients from its Pennsylvania-based service laboratory.
GCC is a gene coding for a protein, which is expressed in colorectal cells, both normal and cancerous, but is never found in normal tissue in other parts of the body. When GCC is detected in lymph nodes removed during colorectal cancer surgery, it is an indication of the presence of colorectal cancer metastases.
The study’s principal investigator, Dr Scott Waldman, Chairman of the Department of Pharmacology and Experimental Therapeutics at Thomas Jefferson University, stated “Patients with cancer cells in their regional lymph nodes carry a worse prognosis and a higher risk of recurrence; detecting GCC in the patient lymph nodes could be useful for identifying patients who might benefit from treatment with adjuvant chemotherapy.”
In a group of 257 colorectal cancer (CRC) patients who were thought to have a lower risk of recurrence according to histopathology (stage I and II patients), when GCC was considered independently from other factors, patients whose nodes were GCC positive were 4.7 times more likely to develop disease recurrence than those whose nodes were GCC negative, and 3.3 times more likely to die within three years. In fact, patients with GCC positive nodes had a risk of recurrence and survival rate comparable to that of patients considered higher
risk by histopathology (stage III).
Currently, most patients who are considered to have a lower risk of recurrence by histopathology do not receive adjuvant treatment, such as chemotherapy, after their surgery. However, it is widely recognized that histopathology, which consists of microscopically examining thin slices of the lymph nodes, is imperfect and up to 30% of histopathology node-negative patients experience disease recurrence and face greater risk of death. Guanylyl cyclase C is the first validated marker useful in detecting the presence or absence of CRC cells in the regional lymph nodes, using a technology that is 100,000 times more sensitive than the current microscopic method. With GCC testing, patients who are most likely to experience CRC recurrence can receive appropriate treatment, while those who are at lower risk of disease recurrence can avoid the negative side effects of treatment.
“The results from this study, published in the peer-reviewed Journal of the American Medical Association, provide strong evidence that GCC matters when it comes to predicting the risk of colorectal cancer recurrence and is a major advance for the individualized treatment of colorectal cancer patients. With our very sensitive GCC-based test, physicians and their patients now have an opportunity to use the latest genomic technology to help them make the best possible treatment decisions,” said John Schafer, president and CEO of DiagnoCure.
Every year in North America, 174,000 people are diagnosed with colorectal cancer and 61,000 die from it.
