Second primary malignancy risk in thyroid cancer survivors: a systematic review and meta-analysis.
OBJECTIVE
To determine the risk of second primary malignancies (SPMs) in thyroid cancer survivors.


METHODS
We performed a systematic review and meta-analysis examining the standardized incidence ratios (SIRs) of SPMs in thyroid cancer survivors (compared to individuals without thyroid cancer). Two independent reviewers screened citations and reviewed all full-text papers deemed potentially relevant. Final consensus was reached on inclusion of papers in the review. Data were pooled using fixed effects models.


RESULTS
Thirteen full-text papers were included. The incidence of SPMs in thyroid cancer survivors was increased with an SIR of 1.20 (95% confidence interval 1.17, 1.24) (based on pooled data from six studies of 70,844 thyroid cancer survivors). The SIR of the following SPMs was significantly increased: salivary gland, stomach, colon/colorectal, breast, prostate, kidney, brain/central nervous system, soft tissue sarcoma, non-Hodgkin's lymphoma, multiple myeloma, leukemia, bone/joints, and adrenal. A significantly reduced risk of lung and cervical cancers was observed.


CONCLUSIONS
Thyroid cancer survivors are at increased risk of SPMs, which may be related to disease-specific treatments or genetic predisposition.
Subramanian
Shoba
S
Endocrinology, Stanford University, Palo Alto, California, USA.
Goldstein
David P
DP
Parlea
Luciana
L
Thabane
Lehana
L
Ezzat
Shereen
S
Ibrahim-Zada
Irada
I
Straus
Sharon
S
Brierley
James D
JD
Tsang
Richard W
RW
Gafni
Amiram
A
Rotstein
Lorne
L
Sawka
Anna M
AM
D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D016609:Neoplasms, Second Primary / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D012307:Risk Factors; D013964:Thyroid Neoplasms