Israel Medical Association Journal

Background: More than 90% of all thyroid cancers are differentiated thyroid carcinomas (DTC) with a 10 year survival rate greater than 90%. The commonly used risk stratification systems for DTC include: European Organization for Research and Treatment of Cancer (EORTC), AGES (Age, histologic Grade, Extent of tumor, Size), AMES (Metastasis) and MACIS (Completeness of resection, local Invasion). Other systems are also utilized. Several new factors that may be involved in DTC risk stratification have emerged in recent studies, with other "traditional" factors being challenged. 

Objectives: To present recent updates in the literature on new potential prognostic factors for DTC.

Methods: We conducted a literature review and analysis of publications regarding DTC prognostic factors or risk stratification published in the last 10 years. 

Results: Several new factors with potential prognostic implications for DTC were noted, including family history, lymph node involvement parameters, positive PET-CT findings, multifocal disease, thyroglobulin level and several molecular markers including BRAF. Increasing age is associated with poorer outcome in DTC; however, recent studies suggest that the cutoff point of 45 years may be contested. Furthermore, several studies have shown contradictory results regarding male gender as a negative prognostic factor, thus questioning its prognostic significance. 

Conclusions: A number of new factors with potential prognostic implications for DTC have emerged and should be addressed. However, their role and possible inclusion in new staging systems has yet to be determined.

 

Background: Radiation exposure is a well-known risk factor for well-differentiated thyroid cancer (WDTC). However, disease characteristics, optimal treatment, time from exposure to disease appearance, and the effect on outcome of age at initial exposure have yet to be determined. 

Objectives: To identify the characteristics of radiation-induced thyroid carcinoma.

Methods: We retrieved the charts of all patients previously exposed to radiation who were diagnosed with WDTC between the years 1985 and 2013 in a tertiary referral center. 

Results: Forty-four patients were reviewed. Median time from radiation exposure to diagnosis was 23 years. These patients had higher rates of aerodigestive symptoms and distant metastases on presentation than seen in non-radiated patients. Patients who were exposed to radiation before age 15 years tended to develop the disease at a younger age but had a longer latency period (34.7 ± 15.3 vs. 16.3 ± 10 years, P < 0.001) and none had significantly higher rates of vocal cord palsy, hoarseness on presentation, or aggressive variants on histology compared to patients exposed to radiation at an older age. Disease-specific survival (DSS) was the same for both groups and were similar to that seen in the general population (95% 20 year DSS).

Conclusions: Radiation-induced thyroid cancer has a more aggressive presentation and the age at exposure affects the presentation of disease. Nonetheless, appropriate treatment leads to a favorable prognosis.