Screening high-risk populations for thyroid cancer.

Area of Science:

• Oncology
• Radiology
• Diagnostic Accuracy

Background:

• Children exposed to radiation (radiotherapy or environmental) face increased risk of developing thyroid cancer.
• Optimal screening methods for these high-risk pediatric populations remain undetermined.
• This review assesses diagnostic test accuracy for thyroid nodules and cancer in radiation-exposed children.

Purpose of the Study:

• To systematically review the accuracy of ultrasound and palpation in detecting thyroid nodules.
• To evaluate the diagnostic performance of fine needle aspiration (FNA) for thyroid cancer.
• To compare screening strategies for radiation-exposed children at risk for thyroid cancer.

Main Methods:

• Systematic literature search of MEDLINE (since 1966) using "thyroid neoplasms" and diagnostic test terms.
• Inclusion of studies reporting test performance, gold standard, and biases; analysis of patient surgical outcomes.
• Development of decision models for screening 10,000 medically and 10,000 environmentally irradiated patients.

Main Results:

• Ultrasound sensitivity for nodules (10-41%) surpasses palpation, which is size-dependent (95-100% specificity).
• Fine needle aspiration (FNA) sensitivity (71-95%) and specificity (52-99%) are affected by exclusion of non-diagnostic results.
• Ultrasound screening detects more thyroid cancer (e.g., 275 vs. 125 cases in 10,000 medically irradiated patients) but increases surgeries for benign nodules.

Conclusions:

• Initial ultrasound screening identifies more thyroid cancer cases than palpation across exposure types.
• Ultrasound screening leads to a higher rate of surgeries for non-malignant nodules compared to palpation.
• Palpation screening offers limited reassurance due to a significant rate of undetected nodules in high-risk patients.