Lees A W, Burns P E, Grace M
Int J Cancer. 1978 Dec;22(6):700-7. doi: 10.1002/ijc.2910220611.
The results of a prospective study on oral contraceptive use and breast disease in northern Alberta are presented. The study groups comprised all women aged 30 to 49 examined in diagnostic breast clinics at the Cross Cancer Institute between 1971 and 1974. Three hundred and one patients had breast cancer, 692 had a subsequent biopsy for a benign breast condition, and 548 had no subsequent biopsy. A tendency for an increased relative risk (RR) of breast cancer in women taking oral contraceptives for periods of 1 to 5 years was evident, with relative risk decreased or unaffected in users of less than 12 months (RR = 0.6) or more than 5 years (RR = 1.0). A slightly increased risk was apparent in patients using oral contraceptives within a year prior to attendance at the clinic (recent users); this increase was emphasized when recent users with a prior biopsy for benign breast disease were analyzed alone (RR = 5.0). In women with a prior breast biopsy, use of oral contraceptives for more than 5 years increased risk of breast cancer nine-fold. Former users who had taken oral contraceptives for less than a year showed a significant reduction in breast cancer risk (RR = 0.3). The risk of benign breast disease was also reduced in former users (RR = 0.6) as well as in long-term users (RR = 0.5).
本文呈现了一项关于艾伯塔省北部口服避孕药使用与乳腺疾病的前瞻性研究结果。研究对象包括1971年至1974年间在十字癌症研究所诊断乳腺门诊接受检查的所有30至49岁女性。301例患者患有乳腺癌，692例因乳腺良性疾病接受了后续活检，548例未接受后续活检。服用口服避孕药1至5年的女性患乳腺癌的相对风险（RR）有增加趋势，服用时间少于12个月（RR = 0.6）或超过5年（RR = 1.0）的使用者相对风险降低或未受影响。在就诊前一年内使用口服避孕药的患者（近期使用者）中，风险略有增加；单独分析有乳腺良性疾病既往活检史的近期使用者时，这种增加更为明显（RR = 5.0）。在有乳腺既往活检史的女性中，服用口服避孕药超过5年使患乳腺癌的风险增加了9倍。服用口服避孕药少于一年的既往使用者患乳腺癌的风险显著降低（RR = 0.3）。既往使用者（RR = 0.6）以及长期使用者（RR = 0.5）患乳腺良性疾病的风险也降低了。
