[Oral contraceptives and breast tumors: which pill?]

Data in 2 epidemiological studies published recently (Pike et al., 1983; McPherson et al., 1983) have suggested, but not demonstrated with certainty, that prolonged use of oral contraceptives (OCs) at an early age, particularly before the 1st full term pregnancy, has been associated with an increased risk of breast cancer. The 1st of these studies, a case-controlled study conducted in California of 314 women under the age of 37 with breast cancer and 314 controls, demonstrated an increased risk when OC use occurred before the age of 25, exhibited a direct relation with duration of use, and essentially refers to contraceptives with elevated "progestagen potency" as primary factors. The preliminary data of another case-controlled study conducted in Great Britain (McPherson et al., 1983), confirmed the hypothesis of increased risk with OC use before the 1st full term pregnancy. However, in this study no significant difference was seen on the basis of type of OC used. These are the 1st studies to show plausible evidence of an association between OC use and breast cancer, they have resulted in various interpretations, and have been received with critical caution. In particular, 1 of the major areas of controversy following publication of Pike's article was the criteria on which he based his "progestagen potency" values. Actually, OCs with elevated progestagen potencies tend also to have elevated estrogen potencies, and it is difficult, if not arbitrary, to discriminate between the effects of the 2hormones. Whether these reports significantly alter OC use remains to be seen, particularly when taking into account the protective effect of OC use against endometrial and ovarian cancer, with an estimated reduction of risk at 40-50% and persisting for many years after cessation of use. It appears prudent, in the face of uncertainty over safety, to discourage use of the preparations associated in Pike's study with elevated risk of breast cancer. On the basis of common sense it is unjustifiable to use preparations with elevated doses when more limited doses are sufficient to obtain the desired effect. Therefore, the OCs currently marketed in Italy are presented and those with elevated estrogen and progestagen potency are identified. The most commonly used OC in Italy, containing 150 mg of levonorgestrel, is situated in an intermediate place in terms of progestagen potency. It should be remembered, finally, that the risk of breast cancer in OC users is considerably less of a worry than concern over vascular pathology.