Age is one of the most important risk factors for breast cancer.
The likelihood of developing the disease generally increases as people grow older. Many diagnoses occur in women over the age of 50, although younger women can also develop breast cancer.
This is one reason screening recommendations often vary by age.
A younger person should not automatically dismiss a suspicious lump simply because breast cancer is less common in that age group.
Conversely, older age does not mean that every breast change indicates cancer.
Symptoms need to be evaluated according to the individual's circumstances rather than age alone.
Family History and Inherited Genetic Variants
Having a close relative with breast cancer can increase a person's risk, particularly when multiple relatives have been affected or when diagnoses occurred at relatively young ages.
Certain inherited genetic variants, including pathogenic variants in the BRCA1 and BRCA2 genes, can substantially increase the risk of breast and some other cancers.
Other genes can also be associated with hereditary cancer risk.
However, most breast cancers are not caused by an inherited pathogenic variant passed down through a family.
A person with no known family history can still develop the disease.
Likewise, having a relative with breast cancer does not mean that someone will inevitably develop it.
People with a strong family history or other indicators of hereditary risk may benefit from discussing genetic counseling and individualized screening with a qualified healthcare professional.
Hormonal and Reproductive Factors
Breast tissue responds to hormones, particularly estrogen and progesterone.
Several reproductive and hormonal factors are associated with breast cancer risk, including the timing of menstruation and menopause, certain reproductive histories, and some forms of hormone therapy.
These relationships are complex and should not be interpreted as evidence that ordinary hormonal changes directly cause breast cancer in every individual.
Hormonal changes during the menstrual cycle can also cause temporary tenderness, swelling, or lumpiness that resolves over time.
Such changes are common, but a new persistent abnormality should still be evaluated.
People considering menopausal hormone therapy should discuss the potential benefits and risks with their healthcare professional, taking into account their medical history and treatment goals.
Breast Density
Breast density describes the relative proportions of fibrous and glandular tissue compared with fatty tissue on a mammogram.
Dense breasts are common and are associated with an increased risk of breast cancer compared with breasts that contain less dense tissue.
Dense tissue can also make some cancers more difficult to see on a mammogram because both dense tissue and many tumors appear white on the image.
Breast density is not something that can be determined reliably by looking at or feeling the breasts.
It is assessed through mammography.
People with dense breasts may need a discussion with their healthcare professional about how density affects their individual risk and whether additional screening is appropriate under local guidance.
Lifestyle and Environmental Factors
Some lifestyle factors are associated with breast cancer risk.
Alcohol consumption increases breast cancer risk, and the risk generally rises with increasing intake.
Regular physical activity and maintaining a healthy weight, particularly after menopause, can help reduce risk. Excess body fat after menopause is associated with increased risk of certain types of breast cancer.
Other factors, including smoking and some aspects of reproductive history, may also influence risk.
However, breast cancer cannot be explained by lifestyle alone.
Many people who develop the disease have no identifiable modifiable risk factor, and some people with several risk factors never develop it.
Healthy habits can support general well-being and may reduce certain risks, but they cannot guarantee that breast cancer will be prevented.
Can Stress Cause Breast Cancer?
Stress can affect sleep, mood, appetite, and many aspects of everyday health.
However, there is no conclusive evidence that ordinary psychological stress directly causes breast cancer.
It is important not to blame people for developing the disease because they experienced a difficult period in life.
Breast cancer develops through complex biological processes involving genetic changes and other factors that are not fully predictable in an individual.
Reducing stress can improve quality of life, but it should not be presented as a substitute for screening or medical evaluation.
Can Breast Cancer Be Prevented Completely?
No current strategy can prevent every case of breast cancer.
Some risk factors cannot be changed, including age, certain inherited genetic variants, and aspects of reproductive history.
Nevertheless, people can take steps that may reduce risk or improve the chances of detecting cancer earlier.
These include regular physical activity, limiting alcohol, maintaining a healthy weight, understanding family history, and following appropriate screening recommendations.
People with substantially elevated inherited risk may have additional options that require specialist advice.
The aim is not to eliminate all uncertainty. It is to understand individual risk and make informed decisions based on the best available evidence.
CHAPTER 4: SCREENING, SELF-AWARENESS, AND THE IMPORTANCE OF EARLY DETECTION
One of the most important misunderstandings about breast cancer is the belief that a person must notice symptoms before the disease can be detected.
In reality, screening is designed to identify certain cancers in people who have no symptoms.
For eligible individuals, screening mammography can detect abnormalities before they become large enough to feel.
This can create opportunities for earlier diagnosis, although screening also has limitations and potential harms that should be discussed with healthcare professionals.
What Is a Screening Mammogram?
A mammogram is an X-ray examination of the breast.