Breast and Thyroid Cancer Association

Abstract

To the Editor: We thank Sioka et al.( 1 Sioka C. Fotopoulos A. Thyroid cancer as second primary malignancy in breast cancer patients. Int J Radiat Oncol Biol Phys. 2009; 73 ([Letter]): 1604 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar ) for their interest our article ( 2 Yadav B.S. Sharma S.C. Patel F.D. et al. Nonbreast second malignancies after treatment of primary breast cancer. Int J Radiat Oncol Biol Phys. 2009; 73: 1489-1492 Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar ). None of the patients in the present study had had a second malignancy before the development of breast cancer. The patient with thyroid cancer developed it 1 month after the breast cancer. It is possible that that the thyroid cancer was pre-existing and was detected by chance after breast surgery or vice versa. She was 35 years old, the age group found to have this association ( 3 Brown A.P. Chen J. Hitchcock Y.J. et al. The risk of second primary malignancies up to three decades after the treatment of differentiated thyroid cancer. J Clin Endocrinol Metab. 2008; 93: 504-515 Crossref PubMed Scopus (257) Google Scholar ). She had no history of cancer in her family. Because she developed thyroid cancer before undergoing radiotherapy, that risk factor was also excluded. She had Stage I, infiltrating ductal breast cancer with estrogen receptor/progesterone receptor-positive tumor status. The histologic type of the thyroid cancer was papillary. Thus, we are with the hypothesis put forward by Sioka et al.( 4 Sioka C. Zouboulidis A. Fotopoulos A. et al. Risk of second primary malignancies in women with papillary thyroid cancer. Am J Epidemiol. 2007; 165: 473 Crossref PubMed Scopus (6) Google Scholar ) that patients diagnosed with either thyroid or breast cancer might have a greater predisposition to develop other cancers and the possible existence of common risk factors for both malignancies. Regarding the possible association of thyroid cancer with breast cancer, Sandeep et al.( 5 Sandeep T.C. Strachan M.W. Reynolds R.M. et al. Second primary cancers in thyroid cancer patients: A multi-national record linkage study. J Clin Endocrinol Metab. 2006; 91: 1819-1825 Crossref PubMed Scopus (136) Google Scholar ) found a 30% increased risk of a second primary cancer after the development of thyroid cancer. They also found an increased risk of thyroid cancer after the occurrence of a variety of these cancers, suggesting possible shared risk factors and treatment effects in the development of these cancers. In contrast, Mayr et al.( 6 Mayr A. Fuger B. Staudenherz A. “Increased incidence of secondary tumours in thyroid cancer patients”: A fact or a sophism?. Eur J Endocrinol. 2007; 157 (369) Crossref PubMed Scopus (3) Google Scholar ) have argued that the investigation for thyroid malignancy in all women with a history of mammary carcinoma should include thyroid ultrasonography in the routine follow-up after surgical intervention for mammary carcinoma. Thyroid Cancer as Second Primary Malignancy in Breast Cancer PatientsInternational Journal of Radiation Oncology, Biology, PhysicsVol. 73Issue 5PreviewTo the Editor: We read with great interest the article titled “Nonbreast Second Malignancies after Treatment of Primary Breast Cancer” in the September 2008 issue by Yadav et al.(1). The authors studied the incidence and risk factors of nonbreast second malignancies among 1,084 treated breast cancer patients with a median follow-up of 12 years. Of these patients, the authors identified 29 patients (3%) with second primary nonbreast cancer that occurred after a median of 7 years. Only 1 case of thyroid cancer developed among all the second non-breast cancers (0.1%). Full-Text PDF