Thyroid nodule medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Medical Therapy
| Thyroid nodule | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Malignant | Benign | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Radioiodine therapy | Hyrperthyroidism evaluation | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hyperthyroidism | Euthyroid | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Antithyroid drugs | No medical treatment required Monitor nodule | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Medical therapy goals in thyroid malignancies and differentiated thyroid cancers (DTC) include:
- To remove:
- Primary tumor
- Disease that has extended beyond the thyroid capsule
- Involved cervical lymph nodes
- To minimize treatment-related morbidity.
- To permit accurate staging of the disease.
- To facilitate postoperative treatment with radioactive iodine, where appropriate.
- To permit accurate long-term surveillance for disease recurrence. Both RAI whole-body scanning (WBS) and measurement of serum Tg are affected by residual normal thyroid tissue. Where these approaches are utilized for long-term monitoring, near-total or totalthyroidectomy is required[1]
- To minimize the risk of disease recurrence and metastatic spread. Adequate surgery is the most important treatment variable influencing prognosis, while radioactive iodine treatment, TSH suppression, and external beam irradiation each play adjunctive roles in at least some patients[2]
A complete surgical resection of involved lymph nodes is one of the most important determinants of prognosis. Presence of lymph node involvement after the resection surgery represent a metastatic disease. The primary tumor in this case is mainly in the site of involved lymph node.[3][4][5]
There is a high risk of complication in thyroid nodule surgery. The most important factors determining surgical complications are:[6]
- The extent of surgery
- The experience of the surgeon
Removal of all thyroid tissue (both normal and nodular) in patients undergoing radioactive iodine remnant ablation or radioactive iodine treatment of residual or metastatic disease, is an important element of initial surgery. It has been recommended to perform a near total or total thyroidectomy, as evidences show it may reduce the risk for neoplasia recurrence within the contralateral lobe. [7][8]
Some experts recommend thyroid hormone administration in the case of benign thyroid nodule in iodine insufficient areas as a treatment. Thyroid hormone administration in larger than needed doses that decrease the serum TSH to subnormal levels, may lead to a decrease in nodule size and may be beneficial in regions of the world with borderline low iodine intake, as it may prevent new nodule formation. However, in iodine sufficient areas, there are insufficient evidences that administrating thyroid hormone may have a beneficial effect on benign thyroid nodules.
If findings of FNA is suspicious for or diagnostic of PTC in a pregnant woman, LT4 therapy should be considered as a primary therapy in order to keep the TSH in the normal range to avoid thyroid related problems in newborn.[9][10]
postoperative RAI remnant ablation
If after complete thyroidectomy, still thyroid tissue is found, ablation of the remaining lobe with radioactive iodine can be considered as an alternative way to complete the resection of tissue.[11]
Recombinant human TSH–mediated therapy
Indications of recombinant human TSH–mediated therapy may be indicated in selected patients with underlying comorbidities making iatrogenic hypothyroidism potentially risky, in patients with pituitary disease who are unable to raise their serum TSH, or in patients in whom a delay in therapy might be deleterious. Such patients should be given the same or higher activity that would have been given had they been prepared with hypothyroidism or a dosimetrically determined activity[12]
Metastases treatment:
Treatment of endocrine metastases should be based on:
- Size of metastatic lesions (macronodular typically detected by chest radiography; micronodular typically detected by CT; lesions beneath the resolution of CT)
- Avidity for RAI and, if applicable, response to prior RAI therapy
- Stability absence of metastatic lesions
| Metastases | Treatment | |
|---|---|---|
| pulmonary metastases | Micrometastases | RAI therapy, and repeated every 6–12 months as long as disease continues to concentrate RAI and respond clinically, because the highest rates of complete remission are reported in these subgroups |
| macronodular metastases | RAI and treatment should be repeated when objective benefit is demonstrated (decrease in the size of the lesions, decreasing Tg), but complete remission is not common and survival remains poor. The selection of RAI activity to administer can be made empirically (100–200 mCi) or estimated by lesional dosimetry or dosimetry to limit wholebody retention to 80 mCi at 48 hours and 200 cGy to the red bone marrow. | |
| brain metastases | Complete surgical resection of CNS metastases should be considered regardless of RAI avidity
CNS lesions that are not amenable to surgery should be considered for external beam irradiation. Whole brain and spine irradiation could be considered if multiple metastases are present. | |
| bone metastases | Complete surgical resection of isolated symptomatic metastases
RAI therapy of iodine-avid bone metastases | |
Pulmonary pneumonitis and fibrosis are rare complications of high-dose radioactive iodine treatment
References
- ↑ Mazzaferri EL (1999). "An overview of the management of papillary and follicular thyroid carcinoma". Thyroid. 9 (5): 421–7. doi:10.1089/thy.1999.9.421. PMID 10365671.
- ↑ Kim TH, Yang DS, Jung KY, Kim CY, Choi MS (2003). "Value of external irradiation for locally advanced papillary thyroid cancer". Int. J. Radiat. Oncol. Biol. Phys. 55 (4): 1006–12. PMID 12605980.
- ↑ Wang TS, Dubner S, Sznyter LA, Heller KS (2004). "Incidence of metastatic well-differentiated thyroid cancer in cervical lymph nodes". Arch. Otolaryngol. Head Neck Surg. 130 (1): 110–3. doi:10.1001/archotol.130.1.110. PMID 14732779.
- ↑ Hay ID, Bergstralh EJ, Goellner JR, Ebersold JR, Grant CS (1993). "Predicting outcome in papillary thyroid carcinoma: development of a reliable prognostic scoring system in a cohort of 1779 patients surgically treated at one institution during 1940 through 1989". Surgery. 114 (6): 1050–7, discussion 1057–8. PMID 8256208.
- ↑ Ito Y, Miyauchi A (2010). "Thyroidectomy and lymph node dissection in papillary thyroid carcinoma". J Thyroid Res. 2011: 634170. doi:10.4061/2011/634170. PMC 2989453. PMID 21113383.
- ↑ Sosa JA, Bowman HM, Tielsch JM, Powe NR, Gordon TA, Udelsman R (1998). "The importance of surgeon experience for clinical and economic outcomes from thyroidectomy". Ann. Surg. 228 (3): 320–30. PMC 1191485. PMID 9742915.
- ↑ Lin JD, Chao TC, Huang MJ, Weng HF, Tzen KY (1998). "Use of radioactive iodine for thyroid remnant ablation in well-differentiated thyroid carcinoma to replace thyroid reoperation". Am. J. Clin. Oncol. 21 (1): 77–81. PMID 9499265.
- ↑ Esnaola NF, Cantor SB, Sherman SI, Lee JE, Evans DB (2001). "Optimal treatment strategy in patients with papillary thyroid cancer: a decision analysis". Surgery. 130 (6): 921–30. doi:10.1067/msy.2001.118370. PMID 11742318.
- ↑ Kuy S, Roman SA, Desai R, Sosa JA (2009). "Outcomes following thyroid and parathyroid surgery in pregnant women". Arch Surg. 144 (5): 399–406, discussion 406. doi:10.1001/archsurg.2009.48. PMID 19451480.
- ↑ Rosen IB, Korman M, Walfish PG (1997). "Thyroid nodular disease in pregnancy: current diagnosis and management". Clin Obstet Gynecol. 40 (1): 81–9. PMID 9103951.
- ↑ Randolph GW, Daniels GH (2002). "Radioactive iodine lobe ablation as an alternative to completion thyroidectomy for follicular carcinoma of the thyroid". Thyroid. 12 (11): 989–96. doi:10.1089/105072502320908321. PMID 12490076.
- ↑ Braga M, Ringel MD, Cooper DS (2001). "Sudden enlargement of local recurrent thyroid tumor after recombinant human TSH administration". J. Clin. Endocrinol. Metab. 86 (11): 5148–51. doi:10.1210/jcem.86.11.8055. PMID 11701668.