| Background and purpose: Thyroid cancer(TC)and Breast cancer(BC)are among the most common cancers in female tumors.According to a number of previous meta-analyses,Breast cancer is one of the most common secondary cancers among women with thyroid cancer,while those with the first breast cancer also have a higher risk of thyroid cancer.Existing research suggests that there may be some common causes(hormonal,genetic and environmental factors)between breast and thyroid cancer.Therefore,In recent years,a number of studies have explored the possible link between breast cancer and thyroid cancer,such as Radiation therapy for breast cancer,Radiation therapy,RT)or radioactive iodine treatment for thyroid cancer(Radioiodine therapy,RAI)therapy or external local radiotherapy treatment in the second primary lung cancer,and thyroid hormone,found in the field of endocrine beta receptors thyroid hormone,estrogen,Molecular biology of sodium/iodide symporter(NIS)and iodine agents elucidate the relationship between the two types of cancer.It is the effects of this treatment that may be responsible for the development of secondary primary cancers and the increased cumulative risk of random genetic errors caused by endogenous and exogenous hormones that drive cell proliferation.This may partly explain why the incidence of another primary malignancy in clinically observed survivors of breast or thyroid cancer is significantly higher than in those who do not have cancer.But the pathogenesis of the two cancers is still unclear.Therefore,the purpose of this article is to investigate the different prognostic factors in patients with breast cancer combined with thyroid cancer and patients with single breast cancer.Methods: By selecting the U.S.national cancer institute SEER(Surveillance,Epidemiology,and End Results Program)eligible clinical data in the database in 2004-2012,according to the number of primary tumors in one of the main "only"(one primary only)to choose,on the basis of both tumor diagnosis time difference into thyroid cancer after breast cancer(B-T)and breast cancer after thyroid cancer group(T-B),Pearson chi-square(Pearson 's chisquare test)analysis combined with single breast cancer patients with breast cancer merging thyroid cancer patients,the difference between the two groups using COX regression model and single factor analysis and multifactor analysis of prognostic factors,study endpoints were Overall Survival(Overall Survival,OS),and follow-up of 10 years,the use of Kaplan Meier-Survival curve drawing method,P value is less than 0.05 think the difference was statistically significant.Results: We counted 440,642 cases of single breast cancer by the SEER database.breast cancer patients merging thyroid cancer accounted for 3,445 patients from 2004 to 2012.According to different diagnosis time of the two primary cancers,b-t patients accounted for 54.7% of the total,while t-b patients accounted for 43.1%.Kaplan-meier analysis showed that marital status,histological grade,tumor size,and estrogen receptor status were significantly associated with 10-year overall survival(OS)in patients with breast cancer merging thyroid cancer or single breast cancer.Prognostic factors for patients with breast cancer merging thyroid cancer included age of diagnosis,site of primary breast cancer,biological behavior,surgery,radiation,and chemotherapy.Considering the timing of the tumor diagnosis,the differences between the B-T group and the T-B group were as follows: primary site of breast cancer(p = 0.007 vs p = 0.287),and ER status(p = 0.140 vs p = 0.001).Conclusion:The age of diagnosis of breast cancer and thyroid cancer is an important prognostic factor in patients with breast cancer merging thyroid cancer.Moreover,the primary site of breast cancer is a unique prognostic factor,which is uncommon in patients with single breast cancer.Later individualized monitoring after diagnosis of primary tumor may have a better prognosis.At the same time,the key clinical combination therapy for two primary cancers should not be neglected.Moreover,the effect of mutual treatment on the other tumor during treatment should be fully considered. |
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