"We have no breast cancer in the family": Why this does not mean you are at low risk

"Very often, when I deliver the news to a woman that she has been diagnosed with breast cancer, the immediate reaction is: How can this be? We don't have it in the family at all," says Prof. Tanir Allweis, Director of the Breast Health System and Director of the Breast Surgery Department at Hadassah Medical Center. "But that's just it, it's not. Morbidity data show that most new patients do not have a significant family history, and certainly not in the first degree, meaning a sister, mother, or daughter."

Contrary to popular perception, the absence of breast cancer cases in the family does not necessarily indicate a low risk of developing the disease. In fact, more than 80% of women diagnosed with breast cancer do not have a significant family history. About 20% of those diagnosed have such a history, and 5% to 10% of cases are related to a known hereditary predisposition.

Risk Factors and Heredity

Breast cancer is the most common malignant disease among women in Israel and worldwide, and one in eight women (about 12.5%) will develop it during her lifetime. The risk increases with age, and the disease is relatively rare before age 40. When it is diagnosed at a young age, the link to a hereditary predisposition is more common.

Also, the father's side of the family is considered a family history that increases the risk, especially when the disease was diagnosed in a first-degree relative (mother, sister, or daughter) at a young age. Family history is particularly significant when more than one relative has fallen ill, especially if the disease was diagnosed before age 50, or when cases of ovarian, pancreatic, or metastatic prostate cancer are also known in the family.

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Genetic Testing and Screening

There are several genes whose mutations are known to increase the risk of developing breast cancer. The most well-known are BRCA1 and BRCA2. Today, it is recommended for healthy women of Ashkenazi or Ethiopian descent to undergo a screening test from age 25 to detect common mutations. It is important to emphasize that a negative result does not rule out the existence of all possible mutations, and in the case of a suspicious history, one should seek genetic counseling.

According to Prof. Allweis, the screening test can save lives. In a retrospective Israeli study, it was found that knowledge of BRCA carrier status before breast cancer diagnosis was linked to diagnosis through monitoring at an earlier stage, less extensive treatments, and better survival.

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Modern Approaches to Diagnosis

Relying on family history alone may leave many women at risk outside of monitoring. A study published in the British Journal of Cancer found that existing criteria miss up to 95% of women under 50 who are at higher than average risk of developing breast cancer.

Prof. Allweis believes that in the era of personalized medicine, it is appropriate that screening tests should be adapted to the risk level of each woman. In the coming months, a system for personal risk assessment based on artificial intelligence and mammography images, called Mirai, is expected to be tested at Hadassah. This system analyzes mammography images and looks for subtle patterns that cannot be identified by the human eye to estimate the risk of developing breast cancer up to five years ahead.

What Should Women Do?

Alongside the recommended monitoring, Prof. Allweis emphasizes that women should be aware of their bodies. If a lump or swelling appears in the breast or armpit, a new change in the shape or size of the breast, a change in the skin, nipple, or discharge - one should turn to a check-up and not delay the clarification.

"It is important to remember that even if breast cancer is diagnosed, the chances of recovery today are better than ever, both thanks to early diagnosis and thanks to advanced treatments," concludes the professor.