Because the studies compared Lymphoseek to blue dye and not radiocolloids, it is not possible to determine whether Lymphoseek outperforms sulfur colloid, Dr. Sondak was quick to point out. However, Lymphoseek provides a welcome expansion of available imaging agents, he said. Lymphoseek will be distributed by Cardinal and should become available during the second quarter of 2013, according to Navidea officials.

How Will Lymphoseek Affect Clinical Practice?

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The introduction of Lymphoseek into clinical practice will not likely cause a transformation in whether or not surgeons use blue dye, Dr. Sondak predicted.  Some surgeons already eschew blue dye in favor of radiocolloids; but surgeons who use blue dye for intraoperative visual identification of nodes are likely to continue to do so, he and Dr. Wallace agreed.

“To me, this is evolutionary, not revolutionary,” Dr. Sondak said. “This is an attempt to incrementally improve sentinel lymph node identification. But the tracer we use is only one aspect; the technology—the detection equipment we use before or during surgery—has also improved. We have a lot of factors to put together.”

The question now, Dr. Sondak said, “is, factoring in the new technology, can using this drug (Lymphoseek) in combination with the latest technology make sentinel node biopsy even better?”

The “single most important” lymphatic imaging equipment advance in recent years has been the availability of single photon emission computed tomography (SPECT)/CT, which is comparable to PET scans, Dr. Sondak noted. SPECT/CT similarly fuses two-dimensional planar lymphoscintograms with three-dimensional imaging CT, he added.

 “When they first came out, they produced two-dimensional black blobs. You could see that something was in the vicinity of the liver, but not where it was exactly. Was it in the liver? Next to the liver? Then they fused CT and PET to give you much more precise, 3-dimensional images and you could see exactly where the hot spot was in the liver, correlated with a lump… Now we see not only that there is a lymph node, but exactly where it is in relation to muscle and blood vessels, and how large the lymph node might be.”

It is not yet clear whether or to what degree Lymphoseek might improve SPECT/CT lymphatic imaging, Dr. Sondak noted. The new agent “might make it more efficient—a faster tracer could be a positive,” he said. “Or it could be we’ve gotten so much better with SPECT/CT that Lymphoseek doesn’t add anything. We don’t know yet.”

Lymphoseek and SPECT/CT are both welcome advances in the field, but more work is needed to determine just how to best use each of these tools.

“All of this is helping us do a better job, and that’s good for our patients,” Dr. Sondak said. “Now the burden is on surgeons and nuclear medicine physicians to ask the question: how do we best use this, if at all, to get the most benefit for our patients?”

Ultimately, the answer to that question will hinge not only on effectiveness and efficiency, but also on cost and reimbursement rates, he noted.