Daily aspirin reduces risk of breast cancer, study finds
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《英国医生杂志》
Taking aspirin seven or more times a week reduces the risk of breast cancer by 28%, a study has found (JAMA 2004;291:2433). The drug reduced the risk of hormone receptor positive tumours but not hormone receptor negative tumours.
In an accompanying editorial, Dr Raymond DuBois of Vanderbilt University, Nashville, Tennessee, described the biochemical mechanism by which inhibition of cyclooxygenase by aspirin could result in lower concentrations of oestrogen (JAMA 2004;291:2488-9).
The retrospective, case controlled study looked at women who had new diagnoses of invasive breast cancer or breast cancer in situ from 1 August 1996 to 31 July 1997 in the Long Island breast cancer study project. The study examined the high rate of breast cancer in this mostly middle class area within 125 miles of New York city. Research had already identified local risk factors as lower parity, late age at first birth, little or no breast feeding, and a family history of breast cancer.
A total of 1508 women with breast cancer and 1556 control patients were interviewed. Most women were white. The women were asked if they had taken aspirin once a week for more than six months. If so, they were asked how often and how many tablets a week they took in the two to five years up to one year before their diagnosis of breast cancer. Women in the control group were asked about use up to one year before their interview. Both groups were asked about use of ibuprofen and also of paracetamol, an analgesic and antipyretic rather than a non-steroidal anti-inflammatory drug. The study did not look at dosages or whether the women used coated or uncoated aspirin.
The lead author, Mary Beth Terry, assistant professor of epidemiology at the Mailman School of Public Health at Columbia University, New York, said the group looked at recent aspirin use. 揑n studies of 慺ormer users挆women who used it five or more years ago梚t didn抰 seem to have any protective effect,?she said. Laboratory studies indicate that aspirin inhibits synthesis of prostaglandin, which in turn inhibits oestrogen production in the breast.
She said that women who used aspirin regularly梥even or more times a week梙ad a 28% reduction in risk (odds ratio 0.72 (95% confidence interval 0.58 to 0.90)). Less frequent users had only a 5% reduction, which was not statistically significant. Women who took ibuprofen also had a lower risk of breast cancer than control patients, but the reduction was less than in women taking aspirin. Paracetamol had no effect.
Aspirin reduced the risk of breast cancer in premenopausal women and postmenopausal women, but the effect was more pronounced in postmenopausal women because there were more of them in the study.
If further studies confirm that aspirin reduces breast cancer risk, women would need to continue taking it regularly. 揊requent use would be predicted to lead to a steady-state reduction in intramammary estrogen and thereby reduce the risk of breast cancer,?the authors write.
揂spirin has side effects, and so do other drugs such as tamoxifen for breast cancer prevention. If we figure out the mechanism of action, we might develop a combination that gets maximum benefits and minimal side effects,?Dr Terry said.(New York Janice Hopkins T)
In an accompanying editorial, Dr Raymond DuBois of Vanderbilt University, Nashville, Tennessee, described the biochemical mechanism by which inhibition of cyclooxygenase by aspirin could result in lower concentrations of oestrogen (JAMA 2004;291:2488-9).
The retrospective, case controlled study looked at women who had new diagnoses of invasive breast cancer or breast cancer in situ from 1 August 1996 to 31 July 1997 in the Long Island breast cancer study project. The study examined the high rate of breast cancer in this mostly middle class area within 125 miles of New York city. Research had already identified local risk factors as lower parity, late age at first birth, little or no breast feeding, and a family history of breast cancer.
A total of 1508 women with breast cancer and 1556 control patients were interviewed. Most women were white. The women were asked if they had taken aspirin once a week for more than six months. If so, they were asked how often and how many tablets a week they took in the two to five years up to one year before their diagnosis of breast cancer. Women in the control group were asked about use up to one year before their interview. Both groups were asked about use of ibuprofen and also of paracetamol, an analgesic and antipyretic rather than a non-steroidal anti-inflammatory drug. The study did not look at dosages or whether the women used coated or uncoated aspirin.
The lead author, Mary Beth Terry, assistant professor of epidemiology at the Mailman School of Public Health at Columbia University, New York, said the group looked at recent aspirin use. 揑n studies of 慺ormer users挆women who used it five or more years ago梚t didn抰 seem to have any protective effect,?she said. Laboratory studies indicate that aspirin inhibits synthesis of prostaglandin, which in turn inhibits oestrogen production in the breast.
She said that women who used aspirin regularly梥even or more times a week梙ad a 28% reduction in risk (odds ratio 0.72 (95% confidence interval 0.58 to 0.90)). Less frequent users had only a 5% reduction, which was not statistically significant. Women who took ibuprofen also had a lower risk of breast cancer than control patients, but the reduction was less than in women taking aspirin. Paracetamol had no effect.
Aspirin reduced the risk of breast cancer in premenopausal women and postmenopausal women, but the effect was more pronounced in postmenopausal women because there were more of them in the study.
If further studies confirm that aspirin reduces breast cancer risk, women would need to continue taking it regularly. 揊requent use would be predicted to lead to a steady-state reduction in intramammary estrogen and thereby reduce the risk of breast cancer,?the authors write.
揂spirin has side effects, and so do other drugs such as tamoxifen for breast cancer prevention. If we figure out the mechanism of action, we might develop a combination that gets maximum benefits and minimal side effects,?Dr Terry said.(New York Janice Hopkins T)