Oral contraceptives and breast disease in premenopausal northern albertan women

Abstract

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).

Oral contraceptive use and early abortion as risk factors for breast cancer in young women

“…Secondly, OC needs to be used with caution in all women with a history of BBD. The amount of data we have on this latter point is very small, but it agrees with the studies of Lees et al (1978) and Brinton et al (1979) both of which suggest that OC at any time in women with BBD may increase the risk of breast cancer. The results of the two studies of Paffenbarger and his colleagues (1977,1979) contradict one another on this point.…”

“…PREVIOUS CASE-CONTROL STUDIES have shown no evidence or, at most, little evidence of an increased risk of breast cancer in users of oral contraceptives (Arthes et al, 1971;fHenderson et al, 1974;Fasal & Paffenbarger, 1975: Paffenbarger et al, 1977Sartwell et al, 1977;Lees et al, 1978;Brinton et al, 1979;Paffenbarger et al, 1979;Vessey et al, 1979). However, large-scale use of these compounds did not begin until the mid-1960s, and it is possible that these studies did not find much evidence of an association because long-term use of oral contraceptives was still uincommon, and there may be a long latent period between first exposure and disease.…”

Breast cancer and combined oral contraceptives: results from a multinational study

“…Most studies have also not found an increase in risk in relation to oral contraceptive use in women with a prior history of benign breast disease (Kelsey et al, 1978;Brinton et al, 1982;Vessey et al, 1983;Rosenberg et al, 1984;CASH, 1986), including the two that specifically assessed risk in women who used oral contraceptives after a benign breast lesion developed (Brinton et al, 1982;CASH, 1986). Lees et al (1978), however, did find an increasing risk with duration of use in women with prior benign lesions and Paffenbarger et al (1980) reported a similar result, but with a less striking trend, in premenopausal women only ;Miller et al (1989) also found an increase in risk in users with prior cystic disease. Pike et al (1981) reported risk in relation to use before a woman's first term pregnancy to be particularly enhanced in women with a history of benign breast disease.…”

Corpus luteum dysfunction and the epidemiology of breast cancer: A reconsideration

“…Janerich et al urged caution in interpreting this finding because benign breast disease may be considered by some physicians a contra-indication for oral contraceptive use (71). However, the association of oral contraceptive use with protection has also been shown prospectively (69). A number of epide-…”