TDT's lymph node test will help identify patients who could benefit from receiving adjuvant chemotherapy, possibly reducing the percentage of recurrences over 5 years and the associated mortality rates.

TDT’s lymph node test is a leap forward in the science of “staging” colorectal cancer. Correct staging is crucial in determining the appropriate treatment therapy for each patient. TDT’s lymph node test uses a technology based on quantifying messenger RNA to detect the presence of guanylyl cyclase C (GC-C) in lymph nodes.

Normally, GC-C is only found in the intestinal lining. If metastasis occurs, GC-C is released into the bloodstream on the surface of colorectal tumor cells. Usually the first place that tumor cells spread is the lymph nodes.

Using histopathology, the current approach to staging, the pathologist examines only thin slices of lymph node tissue, potentially missing a cancer. When looking at each section microscopically, it has been shown that at least 1 cancer cell must be present in every 200 normal cells to detect the spread of cancer. With this system about 20% of patients thought to have disease confined to the colon return with recurrent disease, presumably through micrometastases that have escaped histopathological detection.

In contrast, TDT’s highly sensitive test can detect 1 cancer cell among 10,000,000 cells. In TDT’s lymph node test, minute quantities of messenger RNA are amplified to magnify the presence of cancer cells. This technology provides physicians a significantly more sensitive tool for staging patient with colorectal cancer. Knowing the correct stage when the cancer is initially detected will assist physicians in making the appropriate treatment decision. Early treatment may reduce the possibility of recurrence and associated mortality rate.

How the Test is Processed

At present, GC-C Lymph Node tests are performed only in TDT's clinical laboratories in Pennsylvania, and can be ordered only by physicians. The test requires that lymph nodes removed during colorectal cancer surgery (a minimum of 10 lymph nodes are required, 13 are preferred) be processed and forwarded to TDT's clinical laboratory. TDT's scientists use a process called RT-PCR to amplify the molecular signal of GC-C to determine if it is present in the sample.

Special kits have been developed to expedite the process of shipping the lymph nodes to our scientists for testing. Test results are reported directly back to the ordering physician. Physicians can download a form to fax or mail in the "Ordering A Test" section provided on this web site, or can call 800-431-0689.

IMPORTANT NOTE:
TDT is not a participating Medicare or Medicaid provider and does not bill either of these programs for the costs associated with these tests. TDT will provide the patient with the standard information required by insurance companies for reimbursement. The patient may elect to submit these materials and may receive full, partial or no reimbursement from his or her health care insurer. The patient must agree to assume full and direct responsibility for payment to TDT, Inc. for identified services. Subsequent reimbursement from any national or private insurance programs will be their sole responsibility.