ABSTRACT
Breast cancer (BC) and thyroid cancer (TC) are common malignancies among females. However, the connection between TC and BC is not well understood. To explore the relationship between these two cancers and to determine the effect of second metachronous TC on BC survival, we compared BC patients with or without second primary TC using data from the Surveillance, Epidemiology, and End Results (SEER) database. We extracted data from patients with only BC or TC and from BC patients with a second metachronous cancer from 2000-2014. Differences in the clinicopathological and treatment characteristics between BC patients with or without second metachronous TC were analyzed by chi-square tests. Multivariate analyses of BC survival were performed by using Cox regression models. Comparison of disease-specific survival (DSS) curves between these cohorts was performed with the log-rank (Mantel-Cox) test. Survival analyses were also performed using data from 1980-1994. Within this dataset, we found 1,262 BC cases in which a second metachronous TC (BC2TC) developed, accounting for 3.1% of all metachronous cancers following BC from 2000-2014. No significant differences were found in molecular markers. In addition, the mean age at BC diagnosis was younger in the BC2TC group than in the BC group (55.418 y vs 60.273 y). Half of the BC2TC patients developed TC in the first three years following BC diagnosis. Patients with BC2TC showed better DSS than those with BC alone from 2000-2014 (P<0.001). However, this superiority was not significant from 1980-1994 (P = 0.579) or for TNM stage I BC (P = 0.927) and grade I BC (P = 0.431) from 2000-2014. In conclusion, the incidence of BC2TC has increased dramatically during the past 15 years. In addition, patients with BC2TC showed better DSS than patients with BC alone, especially in cases from 2000-2014.
Subject(s)
Breast Neoplasms/diagnosis , Neoplasms, Second Primary/diagnosis , Thyroid Neoplasms/diagnosis , Adult , Breast Neoplasms/complications , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Databases, Factual , Female , Humans , Middle Aged , Neoplasm Grading , Neoplasm Staging , Neoplasms, Second Primary/complications , Prognosis , Proportional Hazards Models , Receptor, ErbB-2/metabolism , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism , Survival Analysis , Thyroid Neoplasms/complications , Thyroid Neoplasms/pathologyABSTRACT
INTRODUCTION: To explore the effect of a second thyroid cancer (TC) on ovarian cancer (OC) patient survival, we compared OC patients with or without a second primary TC using data from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Data for OC only, female TC only and OC patients with a second TC (OC2TC) from two periods, 2000-2014 and 1980-1994, were extracted from the SEER database. Differences in clinicopathological and treatment characteristics were analysed using the chi-square test. Cox regression analyses were used to identify risk factors associated with OC survival. Disease-specific survival (DSS) and overall survival (OS) curves were compared using the log-rank test. RESULTS: There were 109 OC2TC patients from 2000 to 2014, and significant differences (P < 0.001) in the mean age at OC diagnosis, TNM stage and surgical history were found between OC and OC2TC patients. Several factors, including age, grade, TNM stage, histological type and surgical history, influenced OC survival (P < 0.001). OC2TC patients showed better survival than OC patients from 2000 to 2014, regardless of age, TNM stage or surgical history. However, this superiority was not significant in cases from 1980 to 1994 (P = 0.222 for OS). CONCLUSION: Survival was better with OC2TC than with OC from 2000 to 2014 rather than 1980-1994, suggesting that TC improved the survival of OC patients from 2000 to 2014.
