Reports from the Field - Oncology: Rapid test detects rare tumor cells; New method assesses breast cancer risk
Reports from the Field
Oncology
Rapid test detects rare tumor cells
A rapid genetic test to help physicians evaluate lymph node biopsies for the spread of cancer at the time of surgery was introduced for the first time at the recent meeting of the American Association for Thoracic Surgeons in San Diego. The new test may help cancer patients receive more appropriate treatment, reducing the need to return for additional surgery by detecting the presence of rare tumor cells often missed by conventional microscopic evaluation.
Tony Godfrey, PhD, and James Luketich, MD, both associate professors of surgery at the University of Pittsburgh (PA), developed the genetic test that uses a commercially available instrument designed for rapid gene detection. Using a variation of the polymerase chain reaction (PCR) method of gene detection, Godfrey was able to detect, in less than 30 minutes, the cancer-related gene CEA in lymph node biopsies in cancer patients. The gene signals the presence of micrometastases, or difficult to detect tumor cells, indicating the spread of cancer.
"To properly treat cancer patients, lymph nodes need to be evaluated during surgery," notes Godfrey. "Unfortunately, current intraoperative methods are not sensitive enough to detect micrometastatic disease. As a result, many patients either are undertreated or undergo a second operation, once more sensitive and time-consuming tests identify disease spread. Our goal is to avoid these limitations by providing the surgeon with accurate and sensitive information at this pivotal point in the treatment decision process."
The new test appears to be more sensitive than conventional intraoperative methods that involve visual examination of the lymph nodes under a microscope, which often fails to detect cancer. In some cases, the new test surpassed even "gold standard" histopathology, which uses special tissue stains and preparations to detect microscopic traces of disease but takes anywhere from several hours to several days to provide results, Godfrey and Luketich note.
In a retrospective study, researchers examined lymph node biopsies from 30 esophageal cancer patients deemed cancer-free after surgical treatment. Researchers accurately identified which patients later experienced disease recurrence, indicating that this technique was able to identify early stage disease not detected by traditional histopathology.
In an ongoing prospective study, researchers have analyzed lymph node biopsies from 23 patients with and without cancer. The rapid test correctly identified two patients as positive that were deemed cancer-free during surgery and later deemed positive by final histopathology. The tests also accurately identified one patient as positive who was diagnosed as negative by both intraoperative ad final histopathology methods. This patient experienced disease recurrence several months after surgery.
The instrument used for the rapid gene tests performed in these studies, Smart Cycler, is manufactured by Cepheid in Sunnyvale, CA.
New method assesses breast cancer risk
A minimally invasive technique detected atypical cells in 23% of women at high risk of developing breast cancer, according to updated results of a large scale clinical trial presented at the recent American College of Obstetricians and Gynecologists (ACOG) meeting held in Chicago.
Ductal lavage is a method of collecting large numbers of cells from the breast milk ducts, where 95% of breast cancer originates. The procedure involves inserting a hair-thin catheter into the milk ducts and washing the ducts with saline to collect cells.
"Atypical cells significantly increase the risk of breast cancer development," explains William C. Dooley, MD, principal investigator with the University of Oklahoma College of Medicine in Oklahoma City. "This procedure is important news for high-risk women and their physicians who are searching for ways to understand their current risk of developing breast cancer."
The multi-center study enrolled 507 women who were at high risk for breast cancer on the Gail Index.
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