|
Risk:
It has been hypothesized that antibiotics may be associated with an increased risk of cancer. This effect in breast cancer may be because of immune function, inflammation and metabolism of estrogen and phytochemicals. However, this potential relationship has not been fully elucidated.
In a case-control study, 2,266 women at least 19 years of age with primary, invasive breast cancer were compared with 7.953 randomly selected female controls to determine if there is an association between the use of antibiotics and the risk of breast cancer. Of the antibiotics dispensed in the study, 97% were in the following classes: macrolides, tetracyclines, penicillins, cephalosporins, sulfonamides, and quinolones. When patients were divided into 5 groups according to cumulative days of antibiotic use (1 to 51, 51 to 100, 101 to 500, 501 to 1000, and greater than or equal to 1001 days), increasing days of antibiotic use were associated with an increased risk of breast cancer. Similar results were observed for cumulative number of antibiotic prescriptions. These results were noted for all antibiotic classes.
To determine if the indication for the antibiotic is responsible for the relationship rather than the antibiotic itself, 136 patients with acne or rosacea were compared with 65 patients with respiratory tract infections, all of whom took tetracyclines or macrolides for at least 50 days. Results showed no difference in incidence of breast cancer between these groups.
|
