Women showing at least three cellular atypia in their breast tissue are eight times more likely to develop breast cancer compared to healthy patients.
Atypical proliferation
Several previous studies have shown that atypical proliferation (also called atypia) in breast tissue is a major risk factor for breast cancer. Women who are found to have atypia after a breast biopsy are at the highest risk of developing breast cancer. Many such patients are advised to take preventive treatment with drugs such as tamixofen or to take other steps to reduce their risk of breast cancer.
Despite the many studies conducted on this topic, the question still remains whether a family history of breast cancer increases the risk of breast cancer in women with atypia and for how long this increased risk persists in women with atypia.
The Gail model
"The most commonly used tool for predicting breast cancer risk in women with atypia is the Gail model. Applying this model to women with atypia and a family history of breast cancer did not significantly change the estimated risk, which may indicate the low accuracy of this method in predicting for such cases," - believes study author Dr Amy Degnim, a surgeon at the Mayo Clinic. "The results we obtained indicate that women with atypia have a higher absolute risk regarding the development of breast cancer than we expected. This risk is 25 per cent over a 25-year period and is significantly higher in women with calcification and atypia present at multiple sites."
The Gail model is used to estimate risk and uses the following to calculate: age of onset of first menstruation, age of birth of first child, number of previous breast biopsies, presence of atypia and number of close relatives with breast cancer.
It was found that the age of diagnosis of atypia influences the risk of developing cancer - for younger women (under 45 years of age), the risk is twice as high compared to patients diagnosed with atypia after 55 years of age. The number of areas of atypical growths was also significant. With one detected area with atypia, the risk of breast cancer increased 2.3-fold compared to the general female population; the risk is even twice as high when two areas of lesions are detected, and for three or more sites with atypia, the risk increases 8-fold.
The results presented here were obtained from a data review of a group of 331 female patients with atypia. More than half of the patients were aged 55 years when they were diagnosed with atypia (55.9 % of the group) and 42.9 % of the patients had a family history of breast cancer. The majority of women in the study group (68.6 %) had calcification in the tissue taken for biopsy, and 40 % showed multiple sites of atypical lesions.
