Aggressive treatment of anaplastic thyroid carcinoma has dramatically increased survival in the small group of patients who chose to undergo it, say physicians at Mayo Clinic.
Their findings will be presented at the annual meeting of the American Society of Clinical Oncology, to be held June 4-8 in Chicago.
Mayo oncologists say this new approach reflects the need to aggressively treat metastasis even when this rare cancer seems to be confined to the neck. Historically, anaplastic thyroid cancer has been treated with surgery and radiation, but due to rapid spread of microscopic cancer, only between 10 and 20 percent of patients survive past a year. Because the prognosis for this cancer is so poor, Mayo physicians felt that a more aggressive pilot approach that added in chemotherapy early on was merited.
Of 24 patients with newly diagnosed anaplastic thyroid cancer seen at Mayo Clinic between 2003 and 2007, 10 patients with local disease elected to pursue the aggressive approach. After surgery, the patients were treated with intensity modulated radiation therapy (IMRT), a more tailored form of radiation therapy than has been used before, and with aggressive chemotherapy (docetaxel and doxorubicin) in efforts to simultaneously control disease in the neck and forestall metastasis.
One-year survival in this group was 70 percent, with six of the 10 patients (60 percent) alive at least two years post-treatment -- five of them without evidence of disease. Two of these patients were treated more than three years ago and are still in remission.
"The results are far superior to what we have seen before or even expected were possible," says Keith Bible, M.D., Ph.D., a lead investigator of the study, along with Robert Foote, M.D., and Julian Molina, M.D., Ph.D.
However, the benefits come at the cost of toxicity, the researchers add.
"Toxicity is a very real issue, to the point that many patients required hospitalization related to side effects from the therapy, but no deaths resulted from therapy," says Dr. Bible, who is presenting the results. Of the four patients who have died to date, all succumbed to their disease, not to treatment effects.
Dr. Bible added that a clinical trial formally testing two approaches to the addition of chemotherapy to radiotherapy in a randomized fashion will be launched in the fall and will include other centers nationwide. The new study will use a related chemotherapy drug, paclitaxel, as well as the addition of a targeted therapy. Dr. Bible will co-lead the study along with Eric Sherman, M.D., from Memorial Sloan-Kettering Cancer Center and others.
Mayo Clinic is regarded as a center of excellence for the treatment of anaplastic thyroid cancer due to the clinic's specialization in thyroid and endocrine cancers -- an expertise that dates back to the practice of thyroid surgeon Charles H. Mayo, M.D., one of the founders of Mayo Clinic. "We have become seriously focused on how to treat these and other rare endocrine cancers more effectively," Dr. Bible says.
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