Breast Cancer Risk of Hormonal Contraception

Although seems that in younger women baseline risk for breast cancer is extremely low   (13).  Scarce data are available to assign a risk for progestin-only-pill (11).However, the effects of medroxy-  progesterone acetate (MPA)as well as norethisterone (NET)  were investigated in the presence of a growth factor mixture and/ or estradiol in normal and neoplastic human epithelial breast cells,  and it seems that MPA may increase breast cancer risk in women when used in long-term treatment. In this respect NET reacts neutral. The mitosis of pre-existing cancerous cells may be partly inhibited by the addition of both progestogens (14). Thus, these results indicate that it is necessary to differentiate between   normal   and   malignant   breast   cells   concerning   the   assessment   of progestogens as a risk factor for the breast.Data regarding injected or implanted hormonal contraceptives are limited. 

However,  it seems that implants could induce higher risk for breast cancer than injected preparations (OR 8.59); while, associations between injected HC use and breast cancer in women are consistent with   modestly   increased   risk   among   recent   users   and   for   ER   (estrogen receptors) negative tumors.  Based on a small number of users of subdermal implant contraceptives in this study,  a significant increase in breast cancer risk was observed;  continued surveillance of implant users may be warranted (15).

Early breast cancer and ovarian cancer screening are recommended for women with BRCA1/2 mutations. Inherited breast and ovarian cancers account for 10% of all breast and ovarian cancers (16). Relative to sporadic breast and ovarian cancers, these cancers tend to occur at an earlier age and grow more aggressively.

Identification of patients with the mutation is therefore crucial, because preventive measures   such   as   prophylactic   bilateral   mastectomy,  prophylactic   bilateral salpingo-oophorectomy and chemoprevention with Tamoxifen can prevent breast and ovarian cancer (17,18). Likewise,  genetic counseling prior to testing is important,  considering the major impact of the test results on an individual’s life (19,20)  No absolute recommendation is made for or against prophylactic surgery; these surgeries are an option for mutation carriers,but evidence of benefit is lacking,and case reports have documented the occurrence of cancer following prophylactic surgery (21)

Many women would prefer fewer bleeding episodes while taking oral contraceptives.  For this reason and with the intention of reducing menstruation-associated symptoms,  an extended-cycle contraceptive is often considered.  The results of a study ”  in vitro”  indicate that continuously administered ethinylestradiol may not increase breast cancer risk in comparison to intermittent application (22).

However, it remains unknown whether this long-term treatment is associated with a different breast cancer risk from that of the usual treatment.

Another   study   in   vitro   assessed   the   effects   of progesterone (P), testosterone (T),  chlormadinone   acetate   (CMA), medroxyprogesterone (MPA), norethisterone (NET), levonorgestrel (LNG), dienogest (DNG), gestodene (GSD) and 3-ketodesogestrel (KDG) in normal human breast epithelial MCF10A cells and in estrogen and progesterone receptor positive HCC1500 human primary breast cancer cells. The results showed that MPA and CMA,  with growth factors   (GFs),  induced proliferation of MCF10A cells.

While,P,  T,  NET,  LNG,  DNG,  GSD and KDG had no significant effect.  In HCC1500 cells,  MPA and CMA with GFs had an inhibitory effect NET,  LNG, DNG,  GSD,  KDG and T enhanced the proliferative effect of GFs.  P had no significant effect.

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