Jefferson scientists create new test to diagnose colorectal cancer spread

November 29, 1999

The test promises a more accurate picture of the extent of disease

Scientists at Jefferson Medical College have devised a blood test they believe will tell patients whether their colorectal cancer has returned. The test looks for the presence of a protein, GCC, to detect the spread of colorectal cancer to the lymph nodes. It may help doctors better diagnose the disease and provide more appropriate treatment.

Scott Waldman, M.D., Ph.D., Samuel M.V. Hamilton Family Professor of Medicine and director of the Division of Clinical Pharmacology at Thomas Jefferson University in Philadelphia, and his Jefferson co-workers compared two groups of 21 colorectal cancer patients each. One group consisted of patients who had been disease-free for at least six years and deemed "cured." The other group of patients developed recurrent disease within three years after cancer surgery. The latter patients had also been told initially that they had no signs of cancer in their lymph nodes after surgery, meaning their cancer had not spread.

The scientists examined lymph node samples of each patient for the presence of GCC. They found that the disease-free patients' lymph nodes showed no signs of the protein marker. Conversely, GCC was present in every patient whose cancer had returned. They report their results Dec. 7 in the Annals of Internal Medicine.

"The findings suggest that the test can be used to detect metastatic colorectal cancer during the staging of these patients," Dr. Waldman says. "It is more sensitive than current histological methods and the results correlate with disease progression."

Colorectal cancer is the third most common cancer in the nation, with some 200,000 new cases diagnosed annually. It is the fourth leading cause of cancer deaths, and like most cancers, is best treated when found early. Both surgery and chemotherapy are more effective when the disease is still in the intestine. "The single best predictor of how a patient does is whether the disease is confined to the intestine," Dr. Waldman says. "If microscopic seeds have escaped to the lymph nodes, then when a surgeon takes out the cancer, he invariably leaves some behind."

According to Dr. Waldman, as many as 40 percent of colorectal cancers originally thought cured by surgery alone return within about three years.

Staging is the standard way to diagnose cancer. Surgeons remove lymph nodes during surgery and pathologists then examine them under a microscope to look for cancer cells. But the technique all too often misses cancer cells, and physicians would like a more sensitive and accurate method to find disease in the lymph nodes.

That's one reason Dr. Waldman and his co-workers have doggedly searched for such a method. If these initial results hold up in larger clinical trials, he says, doctors may be able to use the test immediately for diagnosing metastatic disease.

"Surgeons can remove the primary tumor and we can confirm the diagnosis using this testing," he explains. "We can use the test for staging - we can get pieces of lymph node and tell patients if they have disease inside or outside the intestine, which is important in deciding about chemotherapy.

"We hope this marker is sensitive and specific for metastatic colorectal cancer," he says. "We want to be able to take lymph nodes judged clean by pathologists in patients told they have disease confined to the intestines, and find disease we wouldn't have found until much later."

Dr. Waldman sees the marker as a useful diagnostic tool for the long run as well. "This marker may be used as a blood test to follow patients after they've had what's thought to be definitive surgery to determine if they have recurrent disease," he explains. "A patient can return for a routine follow-up periodically for blood tests to look for metastatic colorectal cancer cells to know that in fact that he is not in recurrence. If he is, we can possibly intervene sooner."

But, Dr. Waldman says, the study results are only a first step. "It was a small subgroup and this is a retrospective study, conducted after the patients had been diagnosed - we knew ahead of time their diagnoses and we specifically selected them. Now we want to do a large prospective study."

He plans to enroll between 1,000 and 2,000 patients in a large, prospective 5-year study comparing the ability of the standard histological examination of lymph nodes to that of the GCC marker test to predict recurrent disease.

GCC, or guanylyl cyclase C, is a family of seven proteins expressed only by intestinal cells and colorectal cancer cells. It's vital to cellular communications, transmitting signals from outside to inside the cell. It turns out that most sporadic colorectal cancers originate in the cells that line the intestine - cells that normally make GCC. When the cells become cancerous, they continue to make GCC.

The work was funded by the National Institutes of Health and by Targeted Diagnostics & Therapeutics, Inc. (TDT), a privately held biotechnology company based in Exton, Pa. Dr. Waldman is chair of the company's scientific advisory board.

Under the research agreement between TDT and Jefferson, Jefferson owns all patents and the worldwide rights are licensed exclusively to TDT.
-end-


Thomas Jefferson University

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.