| Risk categories |
|---|
| Average risk |
< 1.5 times population risk |
| Moderate risk (Somewhat increased) |
1.5 to 3 times population risk |
| High risk (Substantially increased) |
> 3 times population risk |
The estimated effect of any risk-reducing intervention is calculated by applying the following reductions to both the residual lifetime risk and the 10-year risk (see footnote):
- Risk reducing salpingo-oophorectomy prior to age 45 – a 50% reduction is applied
- Five years of tamoxifen use – a 33% reduction is applied
- Five years of raloxifene use – a 25% reduction is applied
- Five year of exemestane or anastrazole use – a 50% reduction is applied
The estimated breast cancer risk is presented as the risk over the next 10 years as well as residual lifetime risk (up to age 80). This risk is presented in 3 ways, as a statistic, as a pictogram, and as a graph, to account for different preferences for risk communication. The woman’s individual risk is compared to that of an average risk woman of the same age, using age specific breast cancer rates from the Australian Cancer Incidence and Mortality (ACIM), for 2009[5].
After presenting the breast cancer risk, iPrevent™ presents screening and prevention options appropriate to the estimated risk, based on Australian guidelines [4,6]. Options presented may include risk-reducing bilateral mastectomy, risk reducing salpingo-oophorectomy, risk-reducing medication such as tamoxifen, lifestyle modifications such as weight loss and reducing alcohol intake, and breast cancer screening.
Summary of risk reducing options shown according to the risk category:
| Risk Reducing Option Shown | Recommended Risk Category |
|---|
| Risk reducing mastectomy |
High risk category |
Risk reducing salpingo-
oophorectomy |
<=45 years of age and High risk category and
BRCA1/2 mutation
<=45 years of age and High risk category and
at least one relative with ovarian cancer
|
| Risk reducing medication |
| Premenopausal: |
Moderate risk and age >=35
High risk
|
| Post menopausal: |
Moderate risk and age >=35
High risk
|
| Screening: |
All women |
| Lifestyle modifications: |
All women |
Summary of breast screening recommendations:
| Risk Category | Age | Breast Screening Recommendations |
|---|
|
Population risk
|
< 40 years
|
No screening
|
>= 40 and
< 50 years |
2nd yearly mammograms optional
through Breastscreen |
| > 50 years |
2nd yearly mammograms
recommended |
| Moderate risk |
< 40 years
|
No screening
|
| >= 40 years |
Annual mammograms recommended |
| High risk |
< 25 years
|
No screening
|
>= 25 and
< 50 years |
Annual examination and screening -
mammograms /MRI/US |
| >= 50 years |
Annual examination and
mammography
- MRI not usually recommended |
For risk-reducing mastectomy, salpingo-oophorectomy and medication the estimated effect of each option is then presented as a statistic, a pictogram and a graph.
The estimated risk reduction afforded by these strategies is applied according to the following logic (see footnote):
- Risk reducing mastectomy – 90% reduction
- Risk reducing salpingo-oophorectomy under age 45 – 50% reduction
- Five years of tamoxifen– 33% reduction
- Five years of raloxifene – 25% reduction
See links provided on this web page to view prescribing information for risk reducing medications.
iPrevent generates a printable summary report incorporating the risk factors that were inputted, the estimated residual lifetime breast cancer risks and the risk management options and associated risk reductions.
iPrevent was last reviewed for accuracy in May 2018.
Footnote:
This method is only approximate, since these interventions should multiply breast cancer incidence rather than residual lifetime risk. For a woman with high pre-intervention risk, this approximation can underestimate her post-intervention residual lifetime risk, especially for young women. In absolute terms, the underestimation of residual lifetime risk, where it occurs, is at worst no more than 9 percentage points for tamoxifen and 3 percentage points for mastectomy. However, the approximation is very accurate for calculating the post-intervention residual lifetime risks of women with average or moderate pre-intervention risks, and also for calculating the post-intervention 10-year risks of all women, regardless of their pre-intervention risks.
REFERENCES:
- Phillips KA, Liao Y, Milne R L et al. (2019) Accuracy of Risk Estimates from the iPrevent Breast Cancer Risk Assessment and Management Tool. JNCI Cancer Spec. 19;3(4):pkz066.
- Lee AJ, Cunningham AP, Kuchenbaecker KB, Mavaddat N, Easton DF, Antoniou AC, Consortium of Investigators of Modifiers of BRCA1/2, Breast Cancer Association Consortium (2014). BOADICEA breast cancer risk prediction model: updates to cancer incidences, tumour pathology and web interface. British Journal of Cancer. 110(2):535-45.
- Antoniou AC, Cunningham AP, Peto J, Evans DG, Lalloo F, Narod SA, Risch HA, Eyfjord JE, Hopper JL, Southey MC, Olsson H, Johannsson O, Borg A, Pasini B, Radice P, Manoukian S, Eccles DM, Tang N, Olah E, Anton-Culver H, Warner E, Lubinski J, Gronwald J, Gorski B, Tryggvadottir L, Syrjakoski K, Kallioniemi OP, Eerola H, Nevanlinna H, Pharoah PD, Easton DF (2008). The BOADICEA model of genetic susceptibility to breast and ovarian cancers: updates and extensions. British Journal of Cancer. 98(8):1457-66
- Cancer Australia (2010). Advice about familial aspects of breast cancer and epithelial ovarian cancer (accessed September 2015).
- Australian Institute of Health and Welfare (AIHW) (2012). Australian Cancer Incidence and Mortality (ACIM) workbooks (accessed September 2015).
- eviQ Cancer Treatments Online (accessed December 2016).
