Therapy of Thyroid Cancer with Know Positive Neck Nodes, Elevated Tg, And Negative Scan?

Question

I am writing to seek your opinion on a patient who has been treated and followed up by one of my colleagues and recently I was involved in his management. A detailed medical report is attached but briefly he is a 33-year-old man who had papillary thyroid cancer of 4.5 cm size with lymph node mets. He underwent total thyroidectomy and bilateral modified neck dissection in May 1999. He was subsequently treated with 136 mci iodine-131 for local neck uptake and unsuppressed Tg of 0.7 mcg/l. His follow up was marked by slightly elevated unsuppressed Tg levels ( 2.7 and 3.5 mcg/l) but negative diagnostic WBS and essentially negative US examinations. In June 2002, his Tg rose to 1.4 mcg/l while he was on 0.2 mg L-thyroxine. In October 2002, Tg was 29 mcg/l off treatment. Radioiodine Whole body scan is negative but US showed 5 and 8 mm right cervical lymph nodes and FNA from one of them was positive. PET scan showed uptake in the lower neck but no other uptake. CT chest showed no lung mets. The question basically is what would you recommend at this stage? Thank you in advance for your help.

Ali Alzahrani, M.D.,King Faisal Specialist Hospital & Research Center,MBC-46, P.O. BOX 3354, Riyadh 11211, Saudi Arabia.

Response

Your patient has residual tumor at least in neck node(?s). Possibly the nodes would take up RAI and be treated to some extent by a large RAI dose at this point. This approach is followed by some physicians when the source of the TG is unknown. However I would favor first removal of the known positive node (or more likely nodes) by surgery. The stimulated TG of 29 indicates a significant amount of functioning tumor, so the neck nodes may be only part of the problem. If the TG remains signficantly elevated after node resection, and no other source can be identified by neck MRI and US, and his chest CAT is negative, RAI therapy may then be appropriate. You may also want to do abdominal CAT and bone scan in your survey for mets. Of course the value of treating such TG levels “blindly” with large doses of RAI is still debated, but your patient is young and thus aggressive therapy is reasonable.

Leslie J De Groot,MD