Lifestyle modifications
Many modifiable epidemiological risk factors for OC have been described in the general population. In terms of reproductive history, increasing parity, breast-feeding, use of the combined oral contraceptive pill (COCP) and tubal ligation (sterilisation) are all known to protect against OC. This would appear to hold true in BRCA1 mutation carriers but is less clear in BRCA2 carriers (McLaughlin et al., 2007; Antoniou et al., 2009). Clearly, decisions to have children or undergo sterilisation are complex, and neither measure should be advocated purely as a means of reducing the risk of OC. However, it can be encouraging for women to know that they may have reduced their OC risk if they have had children or used the Pill. High-risk women considering tubal ligation should be aware of two issues. Firstly, adhesions following sterilisation could occasionally render subsequent RRSO more challenging, thus increasing the risk of complications. Secondly, if she is unwilling to undergo removal of her ovaries, consideration should be given to sterilisation via salpingectomy rather than tubal ligation alone. Although this slightly increases the procedural time and risks compared with tubal ligation, it should give greater protection against the development of cancer in BRCA1/2 carriers (Dubeau, 2008).
Despite early data to the contrary, infertility treatments do not appear to pose a significantly increased risk of OC, particularly if they succeed (Jensen et al., 2009). Given the association between BRCA1 and subfertility (Oktay et al., 2010), this information may be reassuring for women contemplating assisted conception.
The issue of the COCP is complex, as this has been associated with an increased risk of breast cancer in the general population (Collaborative Group on Hormonal Factors in Breast Cancer, 1996). Risk is thought to depend on current or recent COCP use and disappears 10 years after stopping it. This risk needs to be balanced against the following:
- 1 The COCP remains one of the most reliable and convenient forms of contraception.
- 2 BRCA1/2 carriers already have a very high lifetime risk of breast cancer and will usually undergo surveillance if they do not undergo risk-reducing mastectomy.
- 3 Recent data (Iodice et al., 2010) on COCP formulations since 1975 have not demonstrated an increased risk of breast cancer in BRCA1/2 carriers.
- 4 In the general population, the COCP offers significant reduction in the risk of OC (and also EC) (Beral et al., 2007), which usually carries a worse prognosis than breast cancer, especially if the woman undergoes breast cancer screening. There are also data from the BRCA population, suggesting a reduced risk of OC with COCP use (McLaughlin et al., 2007; Antoniou et al., 2009).
Given these points, rather than specifically advocating the COCP to reduce the risk of OC, it would seem reasonable to explain the advantages and disadvantages of the Pill to women at increased risk of OC and/or breast cancer and let them decide if they want to use it for contraception.
Other modifiable OC risk factors include lack of physical activity, obesity (also a risk factor for EC), smoking and asbestos exposure. Clearly, avoidance of these factors offers many other benefits, and maintaining a healthy weight and avoiding smoking should be encouraged in all women irrespective of their risk of OC. Data on the use of perineal talc as a risk factor for OC are conflicting. It is at worst only a minor risk factor and is easily avoided.
Use of aspirin (Burn et al., 2011) or the levonorgestrel IUS (Wan and Holland, 2011) may reduce the risk of EC in women with LS, but more evidence of efficacy is required.
It is important to note that modifying the above risk factors and protective factors cannot be guaranteed to negate the very high risk of OC and/or EC due to predisposing germline mutations. Consequently, high-risk women must understand that lifestyle modifications cannot be considered a safe alternative to RRSO.
