PDFQuestion
I would appreciate your input. This is a 51 year-old lady who was diagnosed with papillary cancer of the thyroid (4 cm , right lobe), s/p total thyroidectomy on 2/2005.Her primary MD gave her a 30 mCi RAI ablative dose. Themetastatic search showed increase uptake in the thyroid bed. The baseline thyroglobulin was 87.1 ng/ml (NV=0.5-43) with a TSH of 27.0 uiu/ml (NV=0.3-5.0). She was then treated with Synthroid and her subsequent TSH was maintained < 0.5 uiu/ml. The follow-up thyroglobulin on 7/2005 was 7.5 ng/ml. This rose to 11.3 ng/ml on 10/2005. The patient underwent a thyrogen scan showing increase activity in the neck area, and a thyroglobulin level was26.8 ng/ml on 11/2005. Her primary MD then gave a 200 mCi ablative dose on 1/2006. The subsequent metastatic search revealed area of increased accumulation in the neck with physiologic distribution throughout the body. She was then referred to me on 5/2006.She was on 150 mcg of Synthroid and her TSH was 0.22 uiu/ml.Throglobulin level at 3.6 ng/ml. ng/ml. On 11/2006, I did a thyrogen scan and metastatic searchwith no abnormal activity in the neck identified. Unfortunately, my lab did not do the thyroglobulin as requested. After 6 months, on 5/2007, TSH = 0.04 with a Thyroglobulin of 1.5 ng/ml. On 11/2007, a thyrogen scan and metastatic search revealed no uptake in the neck area with physiologic uptake throughout the rest of the body.TSH of 19.2 uiu/mland thyroglobulin of 9.0 ng/ml. Since the 2 previous metastatic searches were negative and with a significant rise in the thyroglobulin, I did a neck ultrasound rather than a radionuclide studyand this revealed on the right a hypoechoic0.7x0.9x0.4 cm nodule, isoechoic lesion in right thyroid bed 0.7x0.3x0.5 cm., mildly hypo/isoechoic tissue in left thyroid bed 0.5x0.7x0.5 cm. I ordered an FNA of the three masses but the radiologist could ony sample the right-sided masses:0.9 cm mass negative for malignancy, 0.7 cm mass positive for metastatic papillary carcinoma. I am in a quandary as to my next step. Would it be better for the patient to undergo surgical removal of all three masses oragain subject her to a 200 mCi RAIablative dose? The surgeon is understandably reluctant to go after the sub-centimeter masses, and she already received 230 mCiover the past 2 years and this may potentially increase her risk of radiation-induced carcinoma. I thank you in advance for your insight.
Patrick Litonjua, MD
Lourdes Hospital
Response
I will offer my view, and note that there may be differing opinions. Concern about leukemia is appropriate, but the total projected RAI dose would be <600mCi even if re-treated, so probably safe. However the prior dose of 200mCi failed to ablate this tumor. Thus I would be strongly in favor of careful reoperation and node removal, and re-evaluation with US, TG and scans at a later date. Treatment with RAI might still be tried if TG remains elevated. Possibly this is a difficult tumor, and even radiotherapy may be indicated at some point in the future. As noted, it would be of interest for readers to write in if they have differing view-points on this case.
Best regards,
L De Groot, MD