Don’t Skip the Checkup: The Science Behind Breast Cancer Screening

• What is Breast Cancer?
• Who is at Risk for Developing Breast Cancer?
• The Importance of Screening for Breast Cancer
• How Do I Know My Breast Cancer Risk?
• Breast Cancer Screening Options
  • Screening Guidelines for Women Age 40 and Younger
  • Screening Guidelines for Women Age 40–49
  • Screening Guidelines for Women Age 50–74
  • Screening Guidelines for Women 75 Years and Older
  • Young Women at High Risk for Breast Cancer
  • Screening for Women With Breast Implants
  • Breast Lump Evaluation While Pregnant or Breastfeeding
  • Screening Dense Breasts
  • Transgender Women With Breasts
• Summary

Key Takeaways

• Breast cancer is the most prevalent cancer worldwide.
• It is also one of the leading causes of cancer death worldwide.
• Mammography screening is the most effective way to find cancer in its early stages.
• Early-stage cancers are easier to treat.
• You are less likely to die from cancer found in its earlier stage than the advanced stage.
• Two main risk factors for breast cancer are being female and advancing age.
• Most women diagnosed with invasive breast cancer do not have identifiable risk factors. Therefore, an average risk is not permission to omit screening.
• Some young women are at high risk for breast cancer despite their age, for example, women who test positive for genetic mutations such as BRCA and those previously treated with radiation therapy.

What is Breast Cancer?

Breast cancer is a condition where the tissue in your breast grows out of control. According to the World Health Organization, as of the end of 2020, breast cancer is the most prevalent cancer worldwide. It is also one of the leading causes of death worldwide, accounting for 685,000 deaths in 2020.

In the United States, except for skin cancer,  breast cancer is the most commonly diagnosed cancer in women. It is the second leading cause of cancer death among American women and the leading cause among Hispanic women. A woman’s lifetime risk of developing breast cancer is approximately 12%, or 1 in 8.

Who is at risk for developing Breast Cancer?

The first risk factor for breast cancer is being female.

• more than 99% of cases occur in women
• a woman’s lifetime risk is 1 in 8
• a man’s lifetime risk is 1 in 883

The second leading risk factor for breast cancer is advancing age. As women get older, their breast cancer risk increases.

Although other risks have been associated with breast cancer, most women diagnosed with invasive breast cancer do not have identifiable risk factors.

Risk Factors You Cannot Control:

• Family history of breast cancer, ovarian cancer, or other hereditary breast and ovarian syndrome-associated cancer
• Gene mutation (BRCA mutations)
• Prior breast biopsy with specific pathology
  • Atypical hyperplasia (Lobular or Ductal)
  • Lobular carcinoma in situ
• Young age at onset of menstruation
• Older age at menopause
• Increasing age
• Dense breasts on mammography
• Having received chest radiation in the past
• Certain ethnicities (e.g., increased risk of BRCA mutation in Ashkenazi Jewish women)
• DES (diethylstilbestrol) Exposure

Risk Factors You Can Control:

• Menopausal hormone therapy
• Never being pregnant
• Older age at first pregnancy
• Never breastfeeding
• Being overweight or obese
• Alcohol consumption
• Smoking

The Importance of Screening for Breast Cancer

Breast cancer screening means a woman with no signs of breast cancer is checked to ensure she does not have this condition.

Mammography screening is the most effective way to find cancer in its early stages. Early-stage cancers are easier to treat. There are more treatment options at the early stage, and treatment is more likely to be successful. You are also less likely to die from cancer found in its earlier stage than the advanced stage.

How Do I Know My Breast Cancer Risk?

Most women have an average risk of breast cancer. A lifetime risk of less than 15% of developing breast cancer is considered an average risk.

If you have certain risks, as mentioned above, your lifetime risk of developing breast cancer is likely higher than 15%.

Women with a 20% or greater risk of developing breast cancer in their lifetime are considered high risk. Moderate risk lies between 15-20%.

Discussing with your doctor or healthcare provider is the best tool to calculate your risk. They can make a thorough assessment based on your personal and family history. You and your doctor can discuss your history to determine your risk category. Online calculators for breast cancer risk assessment are also available.

Remember, half of women diagnosed with breast cancer have no identifiable risk factors. An average risk is not permission to omit screening.

Breast Cancer Screening Options

Doctors use several methods to screen women for breast cancer:

• Breast self-examination: routine exam of your breasts in a systematic fashion.
• Breast self-awareness: awareness of your breast’s usual look and feel.
• Clinical breast examination: examination of your breasts and armpit by your health care provider.
• Mammography: x-ray of the breasts. It is the most effective and commonly used screening tool in women 40 and older.
• Breast Ultrasound: a machine that uses sound waves instead of radiation. Sometimes, it is used in younger patients with dense breasts, but it is not recommended as a screening tool. It may be used to evaluate further a lump found on a mammogram.
• Breast MRI: is not recommended for average-risk patients. It may be used in selective high-risk patients or in conjunction with a mammogram to further evaluate a lump or mass.

Screening Guidelines for Women Age 40 and Younger

No screening is recommended for women in this age group at average risk of breast cancer. The number of women with breast cancer in this group is low. Additionally, screening is limited due to dense breast tissue.

If you have discovered a lump or are concerned about your breast health and are under age 40, speak with your doctor or healthcare provider about the best approach for you.

Screening Guidelines for Women Age 40–49

Screening guidelines for average-risk women in this age group vary. Your healthcare provider will discuss the options with you, and you will decide together.

The recommendations are not cut and dry due to the number of false positive results that can occur in younger women. A false positive means that your test has discovered a mass. You undergo further testing, which may include a biopsy, only to be told that this is normal tissue. These tests can create anxiety and stress for certain women and discourage them from future testing.

On the other hand, this process will detect early-stage cancer and be life-saving for a few women. You will decide with your doctor the best approach for your breast health. The most effective screening method used in this age group is a mammogram.

Screening Guidelines for Women Age 50–74

The recommendation for breast cancer screening in this age group at average risk is consistent – mammograms.

The frequency of screening may be yearly or every two years. Most women in the United States are screened annually.

Mammograms have consistently been shown to reduce deaths due to breast cancer in women aged 50 to 74. The benefits of mammographic screening far outweigh the harm if you are 50 or older.

Screening Guidelines for Women 75 Years and Older

If you are 75 or older and healthy, with a life expectancy greater than ten years, you may continue mammographic screening. You and your doctor will discuss whether screening every two years is appropriate.

Some organizations recommend stopping screening mammograms at age 75. This may be reasonable for those in poor health with a life expectancy of less than ten years.

Women in poor health may have difficulty undergoing the rigors of evaluation of mass. Additionally, breast cancer treatment may cause more harm than benefit if their baseline health is not good.

While this may be a difficult decision, we always want to focus on treating the whole person and not just one condition. You and your doctor will decide based on the overarching best interest of your health.

Young Women at High Risk for Breast Cancer

Some young women are at high risk for breast cancer despite their age. Women who test positive for genetic mutations such as BRCA and survivors of childhood cancers who may have been treated with radiation therapy fall in this category.

While no hard and fast rule fits all cases, the screening recommendations for average-risk women will not apply. In this case, screening recommendations will be more aggressive.

You and your doctor will discuss the best regimen for you and the possibility of cancer reduction measures, such as medication or surgery. A consultation with an oncologist may be prudent in determining your best screening regimen.

Screening for Women with Breast Implants

For women who have undergone breast augmentation solely as a cosmetic procedure, the screening guidelines remain the same as with average-risk women.

The implant may create challenges in the imaging test. It may be difficult to compress the breasts, making the interpretation or reading more difficult. But no change in recommendation is made as far as routine screening.

Mammograms are no longer recommended for women with breast implants following breast cancer removal. There is a small risk of cancer recurrence along the chest wall. The screening method recommended is self-breast awareness and exams.

Your doctor or healthcare provider will also physically examine your breast and armpit at annual visits. If there is a concern about a recurrence of your breast cancer after mastectomy, you’ll need an MRI for further evaluation. You and your oncologists will decide if screening with an MRI at regular intervals is needed.

Breast Lump Evaluation While Pregnant or Breastfeeding

When pregnant or breastfeeding, your doctor will not offer screening. Screening is the term used for routine evaluation of your breasts when you have no symptoms.

If you are concerned about a breast lump you have discovered, you may undergo a diagnostic evaluation. A mammogram will not be performed during pregnancy. You can, however, safely undergo a breast ultrasound or MRI.

Typically, the first step is a breast ultrasound. Depending on the results, your doctor may recommend halting further evaluation until you have your baby. If there is a concern for malignancy, your doctor may recommend a biopsy immediately.

For the breastfeeding mom, your options will be more liberal. You can choose to undergo testing while breastfeeding. Your doctor will counsel you about whether it is safe to continue breastfeeding.

If you or your doctor are concerned about the safety of your breast milk during testing, you may pump and discard (pump and dump) the milk produced during your testing period. You may also choose to discontinue breastfeeding, depending on how involved your testing will be.

Screening Dense Breasts

As we get older, the breast tissue is replaced with fat cells. The fat cells are easy to compress and make a clearer breast image on mammograms and ultrasounds.

Increased breast density makes the visualization of breast cancer cells more difficult.

In the US, recent regulations by the Food and Drug Administration require mammogram providers to inform patients about the density of their breasts.

This would allow you to make more informed decisions with your doctor about the best screening tools for your breast health.

Transgender Women with Breasts

There are no standard breast cancer screening guidelines for transgender women. Without guidelines, most healthcare providers follow the same guidelines outlined for cisgender females.

The risk of breast cancer in transgender women is less than that of cisgender women. However, hormone therapy increases their baseline breast cancer risk.

Summary

Breast cancer remains one of the leading causes of death worldwide. Women and age are the most decisive risk factors for developing breast cancer.

A woman’s risk of breast cancer increases with age. Half of the women diagnosed with breast cancer do not have any identifiable risks beyond their age and gender. Having an average risk does not reduce the importance of breast cancer screening.

Speak with your doctor about the best screening regimen for your breast health. If you cannot afford a mammogram, you may contact the Center for Disease Control and Prevention (CDC) for assistance with free or low-cost mammograms.

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Copyright: myObMD, Inc | Author: Lisa Shephard, MD and Dayna Smith, MD | Editor: Jennifer Abayowa | Reviewed September 29, 2023.

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