Neoplastic Risk of Hormonal Contraception
For   several   years   the   role   of   hormonal   contraceptives (HCs)  in   the development of cancer has been explored, in all countries. Their beneficial effects were well documented, but many questions are still raised concerning a possible connexion with malignant tumours ^(1,2). 

Breast Cancer Risk
The clinical impact of the association between hormonal contraceptives use and breast cancer risk is very important considering the widespread HCs use and, that more than a quarter of a million women are diagnosed as having breast cancer in the United States,  annually ⁽³⁾.

Women who are currently combined oral contraceptives (COCs)users or have used them in the past 10 years are at a slightly increased risk of having breast cancer during the next 10 years;  although the additional cancers diagnosed tend to be localized to the breast and they are less advanced clinically than the cancers diagnosed in those who have never used HCs ⁽⁴⁾.

Particular   interest   was   devoted   to   predisposed   women   as   the BRCA1/BRCA2 mutation carriers; although recent international studies reported in those no evidence that the current use of combined oral contraceptives (COCs) might be associated with a risk more strongly than in the general population.

However,  duration of use,  especially before first full-term pregnancy,  may be associated with an increasing risk of breast cancer among both BRCA 1 and BRCA2 mutation carriers ^(5,6,7). Some researchers have suggested that there may be an increase in the risk of breast cancer associated with a prior induced abortion in users or past users of HCs. 

The risk,  if present,  may vary according to the duration of the pregnancy in which the abortion occurred, or to a woman’s age or parity at that time,or the age at menarche, and to have used oral contraceptives for an extended period of time. The breast cancer relative risk (RR) in those with one or more induced abortion was 1.2 fold to women with no history of abortion and was reported greatest (2.0) among nulliparous women whose abortion or abortions occurred prior to 8 weeks’  gestation ⁽⁸⁾.

This risk was slightly higher when the abortion was performed before 20 years of age or after 29 years of age with a relative risk (RR)  of 1.5. The data from these studies do not permit a causal interpretation at this time, nor do they identify any particular subgroup of women with induced abortion histories at enhanced risk of breast cancer ^(8,9,10). In general, no association has been found between spontaneous abortion and the risk for breast cancer ^(1,10).

An association between breast cancer and long-term HC use among young women, beginning close to menarche suggests that puberty, a time when breast epithelial cells are undergoing considerable proliferative activity, are susceptible to genetic damage. In addition, the frequency in this age group of imbalances of adrenal-ovarian maturation might have importance   ^(11,12).