Rising incidence of second cancers in patients with low-risk (T1N0) thyroid cancer who receive radioactive iodine therapy Journal Article
| Authors: | Iyer, N. G.; Morris, L. G. T.; Tuttle, R. M.; Shaha, A. R.; Ganly, I. |
| Article Title: | Rising incidence of second cancers in patients with low-risk (T1N0) thyroid cancer who receive radioactive iodine therapy |
| Abstract: | BACKGROUND: American Thyroid Association guidelines currently recommend the selective use of radioactive iodine (RAI) therapy in patients with well differentiated thyroid cancer (WDTC). Despite these guidelines, RAI ablation has been used routinely in all but the very lowest risk patients with thyroid cancer over the last 30 years. The objective of this study was to evaluate patterns of RAI use and elevated risk of secondary primary malignancies (SPM) in patients with low-risk (T1N0) WDTC. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used to analyze trends in RAI use over time in the United States. To determine the excess risk of SPM, the standardized incidence ratio (SIR) and excess absolute risk (EAR) of various cancers were calculated in the 2 cohorts. Between 1973 and 2007, 37,176 patients with WDTC were followed in the SEER Program, equating to 408,750 person-years at risk (PYR). In total, 14,589 patients received RAI, and SPMs were observed in 3223 patients. RESULTS: During the study period, the rate of RAI use in patients with low-risk (T1N0) WDTC increased from 3.3% to 38.1%. For low-risk patients, the SIR of SPM was 1.21 (95% confidence interval [CI, 0.93-1.54), and the EAR was 4.6 excess cases per 10,000 PYR. SPM with significantly elevated risk because of RAI were salivary gland malignancies (SIR = 11.13; 95% CI, 1.35-40.2) and leukemia (SIR = 5.68; 95% CI, 2.09-12.37). The excess risk of leukemia was significantly greater in patients aged <45 years (SIR = 5.32; 95% CI, 2.75-9.30) compared with the excess risk in older patients (SIR = 2.26; 95% CI, 1.43-3.39). CONCLUSIONS: The increased risk of a SPM in patients with low-risk (T1N0) WDTC, along with a lack of data demonstrating improved survival outcomes with adjuvant RAI, provide a compelling argument in favor of rationing the use of RAI in this patient population. © 2011 American Cancer Society. |
| Keywords: | cancer survival; middle aged; leukemia; survival rate; overall survival; cancer risk; united states; adjuvant therapy; cancer adjuvant therapy; cancer incidence; incidence; carcinoma, papillary; risk factors; cell differentiation; age; radioactive iodine; iodine radioisotopes; neoplasms, radiation-induced; cancer registry; seer program; thyroid neoplasms; salivary gland cancer; neoplasms, second primary; second cancer; epidemiology; trend study; adenocarcinoma, follicular; surveillance; standardized incidence ratio; differentiated thyroid cancer; radiation-induced; second primary cancer; and end results; radioiodine |
| Journal Title: | Cancer |
| Volume: | 117 |
| Issue: | 19 |
| ISSN: | 0008-543X |
| Publisher: | Wiley Blackwell |
| Date Published: | 2011-10-01 |
| Start Page: | 4439 |
| End Page: | 4446 |
| Language: | English |
| DOI: | 10.1002/cncr.26070 |
| PROVIDER: | scopus |
| PMCID: | PMC3155861 |
| PUBMED: | 21432843 |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 1" - "Export Date: 3 October 2011" - "CODEN: CANCA" - "Source: Scopus" |
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