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Wayne Koch and patient.
Wayne Koch examines a patient whose tumor was removed surgically.


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Finding Left-behind Cancer Seeds


quamous cell carcinoma in the head or neck is not only often disfiguring to patients, but also has a significant chance of recurring. Despite careful surgery, a study in the New England Journal of Medicine showed, roughly half of the patients who’ve undergone tumor removal retain small numbers of cancer cells in the remaining tissue. And of those patients, more than a third see a return of the disease.

Help may be coming, however, in the creation of an exquisitely sensitive new test able to detect the cancer “seeds” left behind. Its sensitivity is roughly 100 times greater than that of the best light microscope in spotting the presence of such cells, says otolaryngologist Wayne M. Koch, M.D. And though the test is still in the trial stage, its use in the near future should tell practitioners which patients need aggressive therapy and which don’t.

The test depends on the presence, in cancer cells, of a mutated form of a gene that normally suppresses cancer development. This well-known suppressor gene, p53, may be mutated in a variety of ways, Koch says, “that are apparently unique for each patient’s tumor.” Using a technique developed by molecular biologist/oncologist/otolaryngologist David Sidransky, M.D., technicians would take a sample of patient’s tissue and extract the DNA, transferring it via molecular biology techniques to laboratory-grown bacterial cells. A radio-labeled probe, which recognizes and binds to mutant p53 DNA, quickly reveals its presence in the bacteria.

The test is available to patients who enroll in multicenter national trials that Koch is now conducting. Patients need provide only a small blood sample. “Though the trial doesn’t mean current patients will have a change in their present treatment,” he says, “we believe the technique will ultimately help us identify those who will.” He predicts the test will be out for clinical use within two or three years.

—Marjorie Centofani



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