The development of breast cancer is primarily influenced by what factor in women of average risk?

The development of breast cancer in women of average risk is primarily influenced by age. As women get older, their risk of developing breast cancer increases significantly. This is due to a combination of factors such as longer exposure to estrogen, which can promote the growth of certain types of breast cells. Although younger women can also develop breast cancer, the majority of cases are diagnosed in women over the age of 50. Therefore, age serves as a crucial indicator of breast cancer risk in the general population.

While genetic predisposition does play a role in breast cancer risk—especially in women with a family history of the disease—most cases occur in those without known genetic mutations. Environmental exposure and dietary habits can also contribute to risk factors, but age remains the most significant and well-established factor in the general population. This understanding helps in guiding screening strategies and informing women about their risk levels as they age.