Differentiated thyroid cancer in children and adults: same or distinct disease?
ABSTRACT Differentiated thyroid cancer (Dtc) is a rare disease, especially in children. Differences in the biology and clinical course of Dtc in children, when compared with adults, may be related both to pathogenesis as well as to clinical outcome of the disease. In childhood, the thyroid gland exhibits higher susceptibility to the carcinogenetic effect of ionizating radiation than in adulthood. Papillary thyroid cancer (Ptc) is more prevalent in children in comparison to adult patients. Among molecular events known to occur in papillary thyroid carcinoma, rEt/Ptc rearrangements exhibit higher prevalence in younger patients, while brAF mutations are very rare in this age group. cancer disease presents at a more advanced stage: 1) primary tumour at diagnosis is larger, especially in relation to the volume of the whole gland; 2) neck lymph node involvement is more commonly observed; 3) distant metastases are detected 3-4 times more frequently than in adults. the lungs are almost the sole distant metastatic site in children and pulmonary metastases are nearly always functional. Additionally, recurrence rates tend to be higher in children; nevertheless, cause-specific cancer mortality remains low. Up to now, thyroid cancer guidelines have been formulated on the basis of experience gained in the general population of patients. the peculiarities in childhood disease raise the question of whether it should be considered a distinct subtype, with specifically tailored therapy recommendations. A definitive answer to this question is not possible with the present state of knowledge. In the opinion of the authors, molecular analyses of childhood thyroid cancer may be crucial, as the clinical data have not satisfactorily answered this question.
SourceAvailable from: Sergei Jargin
[Show abstract] [Hide abstract]
ABSTRACT: There is no international consensus on surveillance strategies for differentiated thyroid carcinoma (DTC) after radiotherapy for childhood cancer. Ultrasonography could allow for early detection of DTC, however, its value is yet unclear since the prognosis of DTC is excellent. We addressed the evidence for the question: ‘is outcome of DTC influenced by tumor stage at diagnosis?’.MethodsA multidisciplinary working group answered the sub-questions: ‘is recurrence or mortality influenced by DTC stage at diagnosis? Does detection of DTC at an early stage contribute to a decline in adverse events of treatment?’ The literature was systematically reviewed, and conclusions were drawn based on the level of evidence (A: high, B: moderate to low, C: very low).ResultsIn children, level C evidence was found that detection of DTC at an early stage is associated with lower recurrence and mortality rates. No evidence was found that it influences morbidity rates. In adults, clear evidence was found that less advanced staged DTC is a favorable prognostic factor for recurrence (level B) and mortality (level A). Additionally, it was found that more extensive surgery increases the risk to develop transient hypoparathyroidism (level A) and that higher doses of radioiodine increases the risk to develop second primary malignancies (level B).Conclusion Identification of DTC at an early stage is beneficial for children (very low level evidence) and adults (moderate to high level evidence), even considering that the overall outcome is excellent. These results are an important cornerstone for the development of guidelines for childhood cancer survivors at risk for DTC.Cancer Treatment Reviews 11/2014; 41(1). DOI:10.1016/j.ctrv.2014.10.009 · 6.47 Impact Factor