OverviewThyroid Cancer Epidemiology and Prognostic Variables
Section snippets
Statement of Search Strategies Used and Sources of Information
PubMed was searched using the keywords: differentiated thyroid cancer, TNM staging, BRAF, lymph node metastases, recurrence, mortality, radioactive iodine, incidence, radiation, and surgery. The National Cancer Institute Website was used to access the SEER monographs and the Cancer Facts and Figures Pages. Globocan was also accessed on the internet.
Incidence Rates
A study by Hundahl et al. [1] of the US National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) database found 53 856 cases of thyroid cancer treated in the USA, and summarised the incidence and mortality rates of thyroid cancer from 1985 to 1995 (Table 1). This study is of considerable importance as cancers of the thyroid are relatively uncommon, comprising only 2% of all cancers diagnosed in 2009 in the USA, but involve slightly more than 95% of all cancers of the
Mortality Rates
Mortality records in the SEER database from 1973 to 2001 show relatively stable or slightly improved mortality rates for thyroid cancer per 100 000 patients [5], [9], [10]. However, over the same period, SEER mortality rates measured in terms of relative survival show an overall significant decline (P < 0.05 for trend) in mortality rates in women and an increase in mortality rates in men (P < 0.05 for trend) (Fig. 4) [5], [8].
Clinical Ramifications of Epidemiological Studies
The epidemiological features of thyroid cancer are important to clinicians for several reasons. First, PTC is the main cause of the steadily increasing incidence of thyroid cancer, mainly because it comprises about 85% of all thyroid cancers. Second, during the same period, the incidences of FTC and MTC have remained relatively stable in some studies, and the incidence of ATC has declined. Finally, perturbations of the incidence and mortality rates relate directly to decisions concerning the
Histology
Tumour histology is a critical determinant of patient outcomes; DTC is associated with the best survival rates, and MTC and ATC have significantly poorer outcomes (see Table 1) [1]. There are several histological subtypes of PTC based on the architectural features of the tumour. The most common subtype (follicular variant) has the typical cellular features of PTC with the nuclear grooves and ‘orphan Annie eye’ nuclei, but differs in that most of the tumour has a microfollicular pattern on
Conclusion
Thyroid cancer is on the rise. The reason for this increase is not clear, but it seems to be multifactorial with increased rates of detection only representing part of the equation. Numerous factors affect outcome for patients with DTC, including age, gender, tumour histology, presence of extracapsular extension, tumour size, presence of lymph node or distant metastases, and oncogene expression of the tumour. In spite of these various factors that influence the prognosis of these tumours, only
Conflict of Interest
None declared.
References (78)
- et al.
Variation in relative survival of thyroid cancers in Europe: results from the analysis on 21 countries over the period 1983–1994 (EUROCARE-3 study)
Eur J Cancer
(2006) - et al.
Occult papillary thyroid carcinoma in postmortem species: prevalence at autopsy
Am J Otolaryngol
(2005) - et al.
The thyroid cancer epidemic: is it the dark side of the CT revolution?
Eur J Radiol
(2006) A perspective on the potential health risks of PBDEs
Chemosphere
(2002)- et al.
Papillary and follicular variant of papillary carcinoma of the thyroid: initial presentation and response to therapy
Otolaryngol Head Neck Surg
(2005) - et al.
Long-term impact of initial surgical and medical therapy on papillary and follicular thyroid cancer
Am J Med
(1994) Management of low-risk differentiated thyroid cancer
Endocr Pract
(2007)- et al.
Role of preoperative ultrasonography in the surgical management of patients with thyroid cancer
Surgery
(2003) population-based analysis of survival factors in differentiated and medullary thyroid carcinoma
Otolaryngol Head Neck Surg
(2003)- et al.
Thyroid tumors with preoperative recurrent laryngeal nerve palsy: clinicopathologic features and treatment outcome
Surgery
(2006)
A National Cancer Data Base report on 53,856 cases of thyroid carcinoma treated in the U.S., 1985–1995
Cancer
Anaplastic thyroid cancer: molecular pathogenesis and emerging therapies
Endocr Relat Cancer
Cancer facts and figures 2009
GLOBOCAN 2000: cancer incidence, mortality and prevalence worldwide. Ver. 1.0. IARC Cancer Base No. 5
Cancer of the thyroid
SEER Cancer statistics review, 1997–2003
International patterns and trends in thyroid cancer incidence, 1973–2002
Cancer Causes Control
SEER Cancer statistics review, 1975–2001
SEER stat fact sheets
Increasing incidence of thyroid cancer in the United States, 1973–2002
JAMA
Prevalence of papillary microcarcinoma of the thyroid in Brazilian autopsy and surgical series
Endocr Pathol
Prevalence rate of thyroid diseases among autopsy cases of the atomic bomb survivors in Hiroshima, 1951–1985
Radiat Res
Rising thyroid cancer incidence in the United States by demographic and tumor characteristics, 1980–2005
Cancer Epidemiol Biomarkers Prev
Increasing incidence of differentiated thyroid cancer in the United States, 1988–2005
Cancer
Time trends for thyroid cancer in northwestern Spain: true rise in the incidence of micro and larger forms of papillary thyroid carcinoma
Thyroid
Managing small thyroid cancers
JAMA
Follicular variant of thyroid papillary carcinoma: a clinicopathologic study of six cases
Am J Surg Pathol
Risk of differentiated thyroid cancer in relation to adult weight, height, and body shape over life: the French E3N cohort
Int J Cancer
Health outcomes of low-dose ionizing radiation exposure among medical workers: a cohort study of the Canadian national dose registry of radiation workers
Int J Occup Med Environ Health
An epidemiologic study of thyroid cancer in Hawaii
Cancer Causes Control
A population-based case–control study of thyroid cancer
J Natl Cancer Inst
Children’s exposure to polybrominated diphenyl ethers
Acta Paediatr Suppl
Follicular variant of papillary thyroid carcinoma: a long-term follow-up
Arch Surg
Pure versus follicular variant of papillary thyroid carcinoma: clinical features, prognostic factors, treatment, and survival
Cancer
Clinical features and outcome of the tall cell variant of papillary thyroid carcinoma
Laryngoscope
Poorly differentiated thyroid carcinoma: the Turin proposal for the use of uniform diagnostic criteria and an algorithmic diagnostic approach
Am J Surg Pathol
Thyroid carcinoma: papillary and follicular
Value of preoperative ultrasonography in the surgical management of initial and reoperative papillary thyroid cancer
Arch Surg
Prophylactic lymph node dissection for papillary thyroid cancer less than 2 cm: implications for radioiodine treatment
J Clin Endocrinol Metab
Cited by (426)
Cancer survival in the northwestern of São Paulo State, Brazil: A population-based study
2023, Cancer EpidemiologyImpact of fine-needle aspiration cytology in thyroidectomy extent and associated surgical morbidity in thyroid cancer
2024, Langenbeck's Archives of SurgeryA study of variation in therapeutic approach to low-risk differentiated thyroid cancer in the UK
2024, Journal of Laryngology and Otology