New lymph node-detecting method could be better for breast cancer patients

Considering the limitations of current methods of locating sentinel lymph nodes (SLNs) in breast cancer patients, a new clinical trial might pave the way for a safer and easier of detection.

The results of the trial were published in the Journal of Nuclear Medicine.

Currently, physicians follow the path of injected blue dye to find the locations of SLNs in breast cancer patients to see if the cancer has spread. But the current method has certain limitations, the authors pointed out, including possible complications from the blue dye and the short amount of time the dye stays connected to the lymph nodes (making it difficult for doctors to find them in time to mark them for biopsies).

These drawbacks are a problem, because as the study authors said, “The metastatic status of SLNs might be the most important prognostic factor in breast cancer,” so it is necessary that physicians can easily, accurately and quickly locate them so they’re able to remove them and perform biopsies.

A new method that might eliminate some of these problems was shown to be effective in this trial in Beijing between 2005 and 2011. It included more than 2,300 breast cancer patients who received the new treatment either before or during surgery.

The method requires an injection of a new radiotracer called Tc-99m-rituximab. It is longer-retained in the SLNs (and is specifically attracted to them, so won’t drift to other areas of the body), which allows doctors more time to identify them and possibly remove them for biopsy. And it eliminates concerns about the risks of blue dye, especially in people with allergies to the substance, according to a statement released about the study.

And the new method might turn out to be a more accurate way to identify SLNs for potential biopsy. After dose-controlled injection, a SPECT system performed a planar lymphoscintigraphy to locate the radiotracer in the body. A randomly selected sub-group of 100 of the initial 2,300 patients showed a 100 percent success rate in detecting the SLNs through the lymphoscintigraphy. There was a false negative rate of 2.6 percent, which the study author said is better than the average 6 to 10 percent for other detection methods. The method of using blue dye and a radiotracer only showed a between 89 percent and 97 percent successful detection rate.

A hand-held gamma-detecting probe helped remove the SLNs from the 100 patients, all of whom were able to be biopsied. The process was then repeated on the remaining 2,200 patients with a success rate of 98.8 percent for detection and 99.9 percent for biopsy.

The study authors also speculated a similar method could be used to help determine cancer spread in melanoma patients and said related research would be executed “in due course.”