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35 yo male patient with 8.5 cm tumor of the right lobe of thyroid. Pathology reports poorly differentiatedpapillary, Hurthle, and Follicular cell types. Extensive lymphovascular invasion, 9 out of 15 nodes positive. Modified radical neck dissection was performed and 7/54 nodes positive. Patientreceived 151mc dose of RAI,scan showed no uptake. Followup Thyrogen stimulated scan showed no uptake either. PET scan was neg.Hashimotos antibodies are presenttherefore Tg is not valuable. Follow up CTs show suspicious nodes on the left side of the neck, submandibular. Recent USOctober 2005 showed the submandibular node to be 2.5cm in diameter. TSH is suppressed at .01. The patient is 2 years post initial diagnosis. My question is what is the likely hood that the nodes on the left side are residualcancer? At time of TT nodes on the left were sampled and found to be negative.Should the node be removed out of caution? If the node ispositive should I131 be repeated even though the variants do not seem to absorb iodineor follow with EBRT. What is the long term prognosis for the variants that do not respond to I131and are there other therapies that may be of value. Lungs are clear at this time. Are any of the clinical trials regarding THYCA promising?
Dr. Joshua J. Joaquin,MD, Jaffrey, NH
Response
I have the following thoughts: My question is what is the likely hood that the nodes on the left side are residualcancer? I would suspect that there is a very high likelihood that these are metastatic nodes, based on the size you describe as well as the fact that poorly differentiated carcinomas commonly metastasize locally. At time of TT nodes on the left were sampled and found to be negative.Should the node be removed out of caution? I would not advocate empiric surgery, but an ultrasound-guided fine needle aspiration would be appropriate. Our surgeons generally do not favor doing repeat surgery in the absence of pathology evidence of recurrent disease. If the node ispositive should I131 be repeated even though the variants do not seem to absorb iodineor follow with EBRT. I would not use further radioactive iodine, as you have had no evidence that previous radioiodine doses have accumulated or had any significant clinical impact on this patient's disease. Surgery should be the first option. Whereas one might have made an argument for adjuvant radiation therapy when his first radioactive iodine posttreatment scan was negative, at this point I might only use external radiation if his disease is not surgically resectable, or if surgery identifies significant involvement of major neck structures such as the trachea or esophagus. In general, I do try to minimize use of radiation therapy in such young patients. What is the long term prognosis for the variants that do not respond to I131and are there other therapies that may be of value. The failure of the disease to concentrate meaningful amounts of radioiodine may be a surrogate marker for disease of poorer prognosis, or simply may indicate that other treatment options are less effective in such patients. Rarely do we recommend systemic therapy such as chemotherapies for residual neck disease, or in a postoperative adjuvant mode. Instead, it is usually reserved for those patients with progressive, symptomatic distant metastatic disease unresponsive to radioodine. All other treatments are of experimental value only, except of course for the primary modalities of surgery and thyroid hormone suppression. Lungs are clear at this time. Are any of the clinical trials regarding THYCA promising? He probably would not readily qualify for existing clinical trials, in the absence of distant metastases and in the presence of presumably surgically resectable disease. At present, there are about a dozen phase II clinical trials of investiagational therapies for thyroid carcinoma. Whereas it would be premature to say that one trial is more promising than another, a fairly complete listing can be found at www.clinicaltrials.gov.
Steven I. Sherman, M.D. UTMD Anderson Cancer Center