An evidence-based review of poorly differentiated thyroid cancer
- 763 Downloads
Poorly differentiated thyroid cancer (PDTC) presents the endocrinologist and surgeon with challenges of recognition and treatment given the lack of consensus on histopathologic definition and limited literature on surgical and nonsurgical treatment.
We offer an operational pathologic definition for PDTC, which should help guide future work in this area. Poorly differentiated thyroid cancer should include insular and trabecular variants but should not include solid type lesions (included by other workers) or more differentiated tumors that may have poor prognosis such as tall cell, columnar, diffuse sclerosing, and oncocytic lesions. Systematic evidence-based literature reviews focusing on two questions were carried out: (1) is PDTC associated with an intermediate prognosis relative to anaplastic and WDTC? and (2) What are the postoperative treatment options for poorly differentiated thyroid cancer?
We have found level IV evidence that PDTC is intermediate between WDTC and anaplastic cancers in terms of prognosis. It represents a disease where appropriate administration of aggressive treatment not typically necessary for routine WDTC and not effective for anaplastic disease may uniquely result in substantial benefit. Limited level IV data show conflicting results regarding 131I treatment benefit. Given lack of morbidity and potential for benefit, we recommend that 131I therapy be considered in all patients postoperatively. Recommendation regarding external beam radiotherapy (XRT) is based primarily on extrapolation from studies in forms of poor-prognosis WDTC where substantial data exist regarding treatment benefit. We recommend that external beam treatment be considered in all patients with PDTC with T3 tumors without distant metastasis, all patients with T4 tumors, and all patients with regional lymph node involvement.
KeywordsThyroid Cancer Papillary Carcinoma Differentiate Thyroid Cancer Differentiate Thyroid Carcinoma Anaplastic Thyroid Cancer
- 7.Rosai J, Carcangiu ML, DeLellis RD (1992) Tumors of the Thyroid Gland. AFIP fascicle series 3, no.4. Armed Forces Institute of Pathology, Washington, DCGoogle Scholar
- 17.Volante M, Collini P, Nikiforov, Y, et al. (2007) Poorly differentiated thyroid carcinoma: the Turin proposal for the use of uniform diagnostic criteria and an algorithmic diagnostic approach. Am J Surg Pathol in pressGoogle Scholar
- 21.Sobrinho-Simoes M, Sambade C, Fonseca E, et al. (2002) Poorly differentiated carcinomas of the thyroid gland: a review of the clinicopathologic features of a series of 28 cases of a heterogeneous, clinically aggressive group of thyroid tumors. Int J Surg Pathol 10:123–131CrossRefPubMedGoogle Scholar
- 32.Wreesman V, Ghossein R (2002) Genome-wide appraisal of thyroid cancer progression. Am J Pathol 161:1549–1556Google Scholar
- 40.Ford D, Giridharan S, McConkey C, et al. (2003) External beam radiotherapy in the management of differentiated thyroid cancer. Clin Oncol (R Coll Radiol) 15:337–341Google Scholar
- 47.O’Connell M, RP AH, Harmer CL (1994) Results of external beam radiotherapy in differentiated thyroid carcinoma: a retrospective study from the Royal Marsden Hospital. Eur J Cancer 30A:733–739Google Scholar
- 51.Auersperg M, Us-Krasovec M, Petric G, et al. (1990) Results of combined modality treatment in poorly differentiated and anaplastic thyroid carcinoma. Wien Klin Wochenschr 27:267–270Google Scholar
- 56.McConahey WM Hay ID, Woolner LB, et al. (1986) Papillary thyroid cancer treated at the Mayo Clinic 1946 through 1970: initial manifestations, pathologic findings, therapy and outcome. Mayo Clinic Proc 61:978Google Scholar