As an endocrinologist who sees many patients with thyroid carcinoma and is active in postgraduate teaching, I must voice my reservations about some of the recommendations made in the Society of Surgical Oncology (SSO) practice guidelines published in the August 1997 issue of oncology.
Treatment of Papillary Cancer, Benign Nodules
The guidelines mention that, in patients with papillary thyroid cancer, a lobectomy and isthmectomy are sufficient if the other lobe is grossly normal, and that a total thyroidectomy should be considered only in patients with a tumor that is bulky or involves both lobes. The guidelines also state that high-risk patients should be treated with radioiodine ablation, implying that low-risk patients should not receive this therapy.
It is typically impossible to adequately scan for small metastases in patients who have not received remnant ablation. Mazzaferri and Jhiang analyzed the treatment of 1,355 patients with differentiated thyroid cancer over a 40-year period. They found that near-total thyroidectomy plus radioiodine therapy resulted in a distinct outcome advantage in patients with solitary tumors greater than 1.5 cm. I find it difficult to ignore their data. DeGroot has echoed these findings.
The multicentric nature of papillary carcinoma must also be considered. If a patient has a tumor in one lobe, how can one be certain that foci do not exist in the other lobe, unless it is removed? I am not aware of any diagnostic studies that can exclude disease with complete efficiency.
The SSO guidelines recommend that patients with benign nodules be treated with levothyroxine therapy for 3 to 6 months. Although this has been a traditional mode of therapy, numerous recent articles[3-6] refute its effectiveness. One article showed that significant regression occurred only with suppressive doses, which are well known to have adverse effects (eg, osteoporosis).
Use of Radionuclide Scans, Thyroglobulin Levels
The guidelines also recommend obtaining a radionuclide scan for lesions showing follicular cells on fine-needle aspiration (FNA) and observing whether the scan is hot. I feel that all follicular lesions should be removed, given the 10% to 15% chance of concurrent malignancy in a follicular adenoma; although hot nodules are less likely to be malignant, I have seen several cases of thyroid cancer arising from hot follicular adenomas. A scan cannot reliably distinguish benign from malignant lesions and should not be used for this purpose.
The guidelines recommend obtaining thyroglobulin levels for patients with papillary thyroid cancer. I maintain that this test is only of value in thyroidectomized patients who undergo radioiodine remnant ablation; the test would be of little utility in the low-risk patients for whom the guidelines recommend subtotal thyroidectomy, as these patients would still have considerable normal thyroid tissue present.
Finally, I am disturbed that the SSO has recommended these guidelines as a reference for health maintenance organization directors. I feel that many patients would receive inferior care if these guidelines were followed. I will still recommend aggressive therapy for my patients.
Co-Director of Endocrinology
Ball Memorial Hospital