TY  - JOUR
A1  - Reiners, Christoph
A1  - Schneider, Rita
A1  - Platonova, Tamara
A1  - Fridman, Mikhail
A1  - Malzahn, Uwe
A1  - Mäder, Uwe
A1  - Vrachimis, Alexis
A1  - Bogdanova, Tatiana
A1  - Krajewska, Jolanta
A1  - Elisei, Rossella
A1  - Vaisman, Fernanda
A1  - Mihailovic, Jasna
A1  - Costa, Gracinda
A1  - Drozd, Valentina
T1  - Breast Cancer After Treatment of Differentiated Thyroid Cancer With Radioiodine in Young Females: What We Know and How to Investigate Open Questions. Review of the Literature and Results of a Multi-Registry Survey
JF  - Frontiers in Endocrinology
N2  - Published studies on the risk of radiation-induced second primary malignancy (SPM) after radioiodine treatment (RAI) of differentiated thyroid cancer (DTC) refer mainly to patients treated as middle-aged or older adults and are not easily generalizable to those treated at a younger age. Here we review available literature on the risk of breast cancer as an SPM after RAI of DTC with a focus on females undergoing such treatment in childhood, adolescence, or young adulthood. Additionally, we report the results of a preliminary international survey of patient registries from academic tertiary referral centers specializing in pediatric DTC. The survey sought to evaluate the availability of sufficient patient data for a potential international multicenter observational case–control study of females with DTC given RAI at an early age. Our literature review identified a bi-directional association of DTC and breast cancer. The general breast cancer risk in adult DTC survivors is low, ~2%, slightly higher in females than in males, but presumably lower, not higher, in those diagnosed as children or adolescents than in those diagnosed at older ages. RAI presumably does not substantially influence breast cancer risk after DTC. However, data from patients given RAI at young ages are sparse and insufficient to make definitive conclusions regarding age dependence of the risk of breast cancer as a SPM after RAI of DTC. The preliminary analysis of data from 10 thyroid cancer registries worldwide, including altogether 6,449 patients given RAI for DTC and 1,116 controls, i.e., patients not given RAI, did not show a significant increase of breast cancer incidence after RAI. However, the numbers of cases and controls were insufficient to draw statistically reliable conclusions, and the proportion of those receiving RAI at the earliest ages was too low.In conclusion, a potential international multicenter study of female patients undergoing RAI of DTC as children, adolescents, or young adults, with a sufficient sample size, is feasible. However, breast cancer screening of a larger cohort of DTC patients is not unproblematic for ethical reasons, due to the likely, at most slightly, increased risk of breast cancer post-RAI and the expected ~10% false-positivity rate which potentially produced substantial “misdiagnosis.”
KW  - differentiated thyroid carcinoma
KW  - radioiodine therapy
KW  - iodine-131
KW  - long-term complications
KW  - young females
KW  - childhood and adolescence
KW  - second primary malignancy
KW  - breast cancer
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-207766
SN  - 1664-2392
VL  - 11
ER  -