Radioactive Iodine Therapy Did Not Significantly Increase the Incidence and Recurrence of Subsequent Breast Cancer.

Abstract

CONTEXT:

Previous studies on the extent to which radioactive iodine (RAI) therapy for thyroid cancer increases the risk of subsequently developing breast cancer have given conflicting results.

OBJECTIVE:

This study aimed to evaluate the effect of RAI treatment on breast cancer development and recurrence among female patients with primary thyroid cancer.

DESIGN:

This was a retrospective cohort study. The risk of subsequent breast cancer associated with RAI and its dose in hazard ratios (HRs) with 95% confidential intervals (CIs) were calculated using time-dependent Cox proportional hazard models.

PATIENTS:

A total of 6150 patients with thyroid cancer enrolled between 1973 and 2009 were followed until December 2012. Of these, 3631 (59.0%) received RAI therapy. During the follow-up period, 99 primary breast cancers were diagnosed.

MAIN OUTCOME MEASURE:

Risk of breast cancer development according to RAI therapy and RAI dose during treatment for primary thyroid cancer.

RESULTS:

RAI therapy did not significantly increase the incidence of subsequent breast cancer among female patients (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.22-1.06) when a 2-year latency period was accounted for. High-dose RAI (≥120 mCi) was associated with a reduced incidence of subsequent breast cancer (HR, 0.17; 95% CI, 0.05-0.62) in the cohort with a 2-year latency period.

CONCLUSIONS:

The long-term follow-up results of this study suggest that RAI treatment for patients with thyroid cancer may not increase the risk or recurrence of breast cancer.

• Authors: Hwa Young Ahn, Hye Sook Min, Yohwan Yeo, Seung Hyun Ma, Yunji Hwang, Jee Hyun An, Hoon Sung Choi, Bhumsuk Keam, Seock-Ah Im, Do Joon Park, In Ae Park, Dong-Young Noh, Yeo-Kyu Youn, June-Key Chung, Bo Youn Cho, Sue K Park, Young Joo Park
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 100 Issue 9 Pg. 3486-93 (Sep 2015) ISSN: 1945-7197 [Electronic] United States
• PMID: 26147607 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Iodine Radioisotopes

Topics

• Adult
• Breast Neoplasms (epidemiology, etiology)
• Female
• Follow-Up Studies
• Humans
• Incidence
• Iodine Radioisotopes (adverse effects)
• Middle Aged
• Neoplasm Recurrence, Local (epidemiology, etiology)
• Retrospective Studies
• Thyroid Neoplasms (radiotherapy)