Abstract | PURPOSE: The actuarial risk for developing benign or malignant thyroid disease following radiation therapy (RT) is controversial, but may be as high as 50% at 20 years. An effective screening modality should be specific but not overly sensitive, a limitation of ultrasound. We questioned whether Technetium-99 m pertechnetate ((99m)Tc TcO(4)(-)) scanning could detect clinically significant disease in ostensibly disease-free cancer survivors. METHODS AND MATERIALS: Eligibility criteria included an interval of at least 5 years after RT to the cervical region, a thyroid gland that was normal to palpation, euthyroid status determined by clinical examination, free T4 and TSH. The 34 patients scanned included 16 children (<18 years old) and 18 adults at the time of RT, 16 females and 18 males. The mean age at RT was 20 years (range, 2.1-50.3 years), and the mean age at (99m)Tc TcO(4)-scanning was 33 years (range, 13.6-58 years), providing a mean interval of 13 years (range, 5.3-26.6 years). The mean RT dose to the thyroid was 36.4 Gy (range, 19.5-52.5). Thyroid scanning was performed with a 5 mCi dose of (99m)Tc TcO(4)(-) obtaining flow, immediate and delayed static, and pinhole collimator images. RESULTS: Seven patients (21.6%) had abnormal scans, and the percentage was higher among children (25%) and females (25%) compared to adults (16.7%) and males (16.7%), respectively. Two of 34 patients (5.9%) were discovered to have a thyroid cancer; histopathologies were papillary and follicular carcinoma. CONCLUSION: In this population of clinically normal cancer survivors who had been irradiated to the cervical region, subclinical thyroid disease, of potential clinical significance, was detected by (99m)Tc TcO(4)(-) in about 20%. Children may be more commonly affected. Although the cost effectiveness of screening will require a larger sample number, we propose a surveillance schema for this patient population.
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Authors | A Sandhu, L S Constine, R E O'Mara, A Hinkle, A G Muhs, P D Woolf |
Journal | International journal of radiation oncology, biology, physics
(Int J Radiat Oncol Biol Phys)
Vol. 48
Issue 1
Pg. 181-8
(Aug 01 2000)
ISSN: 0360-3016 [Print] United States |
PMID | 10924988
(Publication Type: Case Reports, Journal Article)
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Chemical References |
- Radiopharmaceuticals
- Sodium Pertechnetate Tc 99m
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Topics |
- Adolescent
- Adult
- Carcinoma
(diagnostic imaging, etiology)
- Cerebellar Neoplasms
(radiotherapy)
- Child
- Child, Preschool
- Female
- Hodgkin Disease
(radiotherapy)
- Humans
- Male
- Medulloblastoma
(radiotherapy)
- Neoplasms, Radiation-Induced
(diagnostic imaging, etiology)
- Neoplasms, Second Primary
(diagnostic imaging, etiology)
- Radionuclide Imaging
- Radiopharmaceuticals
- Sodium Pertechnetate Tc 99m
- Thyroid Gland
(diagnostic imaging, radiation effects)
- Thyroid Neoplasms
(diagnostic imaging, etiology)
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