Hormonal content and potency of oral contraceptives and breast cancer risk among young women

Abstract

Recent use of oral contraceptive pills is associated with a modest risk of breast cancer among very young women. In this US population-based case -control study, we evaluated whether the excess risk associated with recent oral contraceptive use is ubiquitous for all pill types or attributable to specific oral contraceptive preparations. Hormonal content and potency of combination oral contraceptives used for the longest duration within 5 years of interview for breast cancer cases aged 20 -44 years (N ¼ 1640) were compared with age-matched community controls (N ¼ 1492). Women who recently used oral contraceptives containing more than 35 mg of ethinyl oestradiol per pill were at higher risk of breast cancer than users of lower dose preparations when compared to never users (respective relative risks of 1.99 and 1.27, P trend o0.01). This relationship was more marked among women o35 years of age, where risks associated with high-and low-dose ethinyl oestradiol use were 3.62 and 1.91 (P trend o0.01), respectively. We also found significant trends of increasing breast cancer risk for pills with higher progestin and oestrogen potencies (P trend o0.05), which were most pronounced among women aged o35 years of age (P trend o0.01). Risk was similar across recently used progestin types. Our findings suggest that newer low-potency/low oestrogen dose oral contraceptives may impart a lower risk of breast cancer than that associated with earlier high-potency/high-dose preparations.

Oral Contraceptives and Survival in Breast Cancer Patients Aged 20 to 54 Years

“…Furthermore, pill types are not prescribed randomly, and no data were available on the reasons women used certain pill formulations. However, our results for high-dose estrogen pills mirror results observed in the parent case-control study for incidence (4). Mortality was higher among recent OC users, regardless of dose and formulation.…”

“…Modeling was done separately for each attribute of OC use: ever use for z6 months, duration, age at first use, age at last use, duration of use before age 25, duration of use before a first birth, time since first use, and time since last use. To be consistent with previous analyses based on the same group of breast cancer patients (4,25), the reference group for all analyses reported here is non-OC users, defined as those who used OCs for less than 6 months (including never users). Results were similar when never users were used as the reference (data not shown).…”

“…To analyze OC dose, potency, and formulation, those who could not recall dates of use or pill types (202 women, 22.5% of users) or used progestin-only pills (6 women, <1% of users) were excluded, similar to our previous analyses (4). Because classification of pill content was complicated for use of multiple pills at different times for varying durations, components of combination OCs used during various periods were analyzed (4).…”

“…Among younger women, current or recent OC use and use of higher dose and potency pills have been associated with modestly higher breast cancer incidence (3,4), but effects on survival are unclear (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). To date, no studies have examined pill characteristics and survival.…”

Efeitos morfológicos, histológicos e moleculares dos moduladores seletivos dos receptores de estrogênios tamoxifeno e raloxifeno na prevenção primária de tumores mamários quimicamente induzidos em ratas

“…Determinados fatores de risco têm influenciado esse aumento (Collaborative, 1996(Collaborative, , 1997(Collaborative, , 2002Garland et al, 1998;Colditz e Rosner, 2000;Lipworth et al, 2000;McPherson et al, 2000;Bernstein, 2002;Marchbanks et al, 2002;Althuis et al, 2003;Colditz et al, 2004;Friman et al, 2007), como as mudanças nos hábitos (maior consumo e ingesta de gorduras não saudáveis, sedentarismo e, conseqüente, aumento no índice de massa corpórea, consumo exagerado de álcool (Fan et al, 2000;Prentice et al, 2006;Michels et al, 2007;Tworoger et al, 2007) e, sobretudo, os fatores reprodutivos que favorecem a maior exposição estrogênica (menarca precoce; uso de anticoncepcionais precocemente e por longos períodos; terapia hormonal; gestação cada vez mais tardia; menor número de gestações; menor tempo de amamentação).…”