Calculate your risk

Calculate your risk for breast, ovarian, and prostate cancer

It can be hard to know if a hereditary cancer test is relevant for you. CanRisk is an online tool you can use to calculate the likelihood that you carry a pathogenic variant associated with hereditary breast, ovarian, and/or prostate cancer – it’s free! The genes accounted for in CanRisk’s calculation are BRCA1, BRCA2, PALB2, ATM, CHEK2, RAD51D, RAD51C, and BRIP1.

In addition to calculating the likelihood of being a carrier, CanRisk can even be used to calculate a woman’s lifetime risk for breast and ovarian cancers. CanRisk considers various parameters in its risk calculation, including lifestyle factors and family history.

Build your family tree

The first step in calculating your likelihood of being a carrier is building a family tree in CanRisk, preferably including both sides of the family. The next step is to fill in any incidences of cancer that could be related to hereditary breast, ovarian, or prostate cancer. For female family members this includes breast, ovarian, and pancreatic cancer. For male family members the relevant cancer types include male breast, prostate, and pancreatic cancer.

Below are three example calculations based on fictitious families.

Family 1

A healthy 35-year-old woman is wondering about her breast cancer risk and the likelihood that she is a carrier of a pathogenic variant. Her mother and aunt (mother’s sister) were diagnosed with breast cancer at ages 50 and 55, respectively, and her grandmother (mother’s mother) was diagnosed with ovarian cancer at age 55. With CanRisk she is able to calculate that her risk of carrying a pathogenic variant in BRCA1 is 4.8 percent, and 7.7 percent in BRCA2. Her total risk of being a carrier, further inclusive of PALB2, ATM, CHEK2, RAD51D, RAD51C, and BRIP1, is 14.8 percent. The woman’s lifetime risk of developing breast cancer is estimated to be 25 percent in the case that no one in the family has undergone genetic testing (the average woman has a lifetime risk of about 10 percent). Should the woman undergo genetic testing of the aforementioned genes and test negative, then her lifetime risk would instead be 17.7 percent. The reason her risk would still be increased is because not all hereditary breast cancer is caused by the genes included in CanRisk.

Family 2

A healthy 20-year-old woman is wondering about her breast cancer risk and the likelihood that she is a carrier of a pathogenic variant. Her grandmother (mother’s mother) and aunt (father’s sister) were diagnosed with breast cancer at ages 70 and 60, respectively. With CanRisk she is able to calculate that her risk of carrying a pathogenic variant in BRCA1 is 0.2 percent, and 0.6 percent in BRCA2. Together with PALB2, ATM, CHEK2, RAD51D, RAD51C, and BRIP1, her total risk of being a carrier is 2.5 percent. Her lifetime risk of developing breast cancer is estimated to be 14.8 percent.

The reason the woman in family one has a significantly higher risk than the woman in family two, both of being a carrier and of developing cancer, is because all incidences of cancer occurred on the same side of the family. Additional factors that contribute to her higher risk are younger age of onset and incidence of both breast and ovarian cancers.

Family 3

A 50-year-old man newly diagnosed with prostate cancer wonders if he carries a pathogenic variant in the BRCA2 gene. His father was diagnosed with prostate cancer at age 65, his mother and aunt (father’s sister) with breast cancer at age 55, and his grandfather (father’s father) with pancreatic cancer at age 60. With CanRisk he is able to calculate that the likelihood of carrying a variant in BRCA1 is 0.8 percent, and 17.6 percent in BRCA2. Together with the aforementioned additional genes his total risk of being a carrier is 20.2 percent.

In the above examples you can see that the risk of being a carrier differs from family to family based on the family’s history. In family 3 there is a significant difference between the risk of carrying a variant in BRCA1 versus BRCA2, because hereditary prostate cancer is most closely associated with pathogenic variants in BRCA2.

Would you like help assessing your risk? Contact our genetic counselor at vagledning@icellate.se or by phone at +46 (0) 8 - 400 548 00.