Risk of contralateral breast cancer in Denmark 1943-80

Risk of second primary breast cancers among women with ductal carcinoma in situ of the breast

“…Studies have reported varying degrees of contralateral breast cancer risk related to previous use of radiotherapy [30,42,44,51,54,55]. The deleterious effect of radiation therapy on the risk of contralateral breast cancer has been shown to be more apparent after 5 years of follow-up [35,56]; in our cohort, the risk did not differ by radiation therapy status after 5 years of follow-up (data not shown).…”

“…After an invasive breast cancer, young age at onset has been found to be a risk factor for ipsilateral tumor recurrence [13] as well as contralateral breast cancer [40][41][42]. Other studies, however, have found no such association [43,44].…”

A case-control study of unilateral and bilateral breast carcinoma patients

“…During 1985 through 1987, Harvey and Brinton, 36 Storm and Jensen, 6 and Horn, Thompson, and Schwartz 35 all reported that a history of radiation therapy for the first primary breast carcinoma was a risk factor for subsequent contralateral disease. Additionally, history of chest-wall radiation for Hodgkin disease of adolescence and early adulthood is well known to result in higher rates of breast carcinomas after an interval of more than 5-10 years.…”

“…[1][2][3][4][5][6] For selected high-risk populations, this incidence rate may double. 10 Nonetheless, patients who have a first primary breast carcinoma generally are not encouraged to undergo prophylactic, contralateral mastectomy for the reasons discussed below.…”

Incidence and risk factors associated with bilateral breast cancer in area with early age diagnosis but low incidence of primary breast cancer: analysis of 10-year longitudinal cohort in Taiwan

“…It is well documented that women who have been diagnosed with a first primary breast cancer had 2-6-fold risk for developing a second contralateral breast cancer compared with normal women who developed primary breast cancer [1][2][3][4][5][6][7][8][9][10][11] Despite a number of studies addressing occurrence and relevant risk factors of bilateral breast cancer, these Western studies have focused on primary breast cancer with age at diagnosis more than 50 years. While most of studies showed the risk for bilateral breast cancer decreased with advancing age, little is known about whether risk factors responsible for occurrence of bilateral cancer in population with late age at diagnosis of primary breast cancer different from those in population with early age at diagnosis of primary breast cancer, such as Korean, China, and Taiwan [12][13][14].…”