Breast cancer is an invasive cancer. It most commonly occurs due to a genetic mutation or damage to DNA. Treatment may involve surgery, radiation therapy, or chemotherapy.

Breast cancer can affect females or males, but this article will focus on the condition in females. Although most breast cancers do not have symptoms, a person may feel a lump in the breast, changes to the nipple, and armpit or breast pain.

Anyone with symptoms of breast cancer should speak with a healthcare professional. Prompt diagnosis and treatment may improve a person’s outlook.

This article explains the symptoms, causes, and types of breast cancer. It also explores treatment options and outlook.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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According to the American Cancer Society (ACS), the most common symptom of breast cancer is a mass or a lump in the breast or an armpit.

Other symptoms may include:

The ACS highlights that most breast lumps are not cancerous. However, anyone who notices a breast lump should see a healthcare professional.

Learn more about breast cancer symptoms.

Breast cancer develops due to genetic changes that can be inherited or acquired (not inherited).

Researchers associate an increased risk of breast cancer with factors such as:

The immune system typically attacks atypical DNA or growths, but it does not do this when a person has cancer.

As a result, cells within breast tissue multiply uncontrollably and do not die as usual. This excessive cell growth forms a tumor that deprives surrounding cells of nutrients and energy.

Learn how breast cancer spreads.

After puberty, female breasts consist of:

  • fat
  • connective tissue
  • lobes, which contain tiny milk-producing glands called lobules

The most common types of breast cancer are lobular carcinoma, which begins in a lobule, and ductal carcinoma, which begins in one of the tiny ducts that carry milk from the lobules to the nipples.

Invasive vs noninvasive

Invasive breast cancer involves cancerous cells spreading to nearby tissue. Cancer may then spread to other parts of the body.

In contrast, noninvasive breast cancer remains in its place of origin. Doctors may consider this a “precancerous lesion.” These cells may eventually become invasive.

Learn more about breast cancer types.

A healthcare professional may stage breast cancer using something called the TNM system, which consists of five different stages. To do this, doctors examine:

  • primary tumor size (T)
  • regional lymph node status (N)
  • distant metastasis (M)

Each category contains substages, which can indicate specific tumor characteristics, such as whether it is positive or negative for a protein called human epidermal growth factor receptor 2 (HER2).

Staging helps healthcare professionals learn whether cancer has spread and determine the best treatment options. People can speak with a doctor about cancer stages and what they mean.

Learn what happens at each breast cancer stage.

The following factors may make developing breast cancer more likely.


The risk of breast cancer increases with age.

According to a 2024 article that cites older research, around 95% of new cases occur in females older than 40.

It states that breast cancer affects 1.5 in every 100,000 females ages 20 to 24, increasing to 421.3 in every 100,000 of those ages 75 to 79.


Females who inherit certain mutations in the BRCA1 and BRCA2 genes have a higher chance of developing breast cancer, ovarian cancer, or both. Mutations in the TP53 gene also have links to an increased breast cancer risk.

If a close relative experiences breast cancer, a person’s chance of developing breast cancer increases.

Testing guidelines

Current guidelines recommend people have genetic testing if their family history includes:

  • breast cancer
  • ovarian cancer
  • fallopian tube cancer
  • peritoneal cancer
  • breast cancer related to BRCA gene mutations

Around 1 in 40 females of Ashkenazi Jewish heritage have a BRCA gene mutation. This can raise their risk of breast cancer.

Experts recommend people with this heritage consider genetic testing if a first-degree relative, such as a sister, experiences breast cancer. They also recommend it if two second-degree relatives, such as a grandmother, on the same side of the family have a history of the condition.

History of breast cancer or breast lumps

A person with a previous history of breast cancer is more likely to develop the condition than a person who has not had it before.

Having some types of noncancerous breast conditions, including atypical ductal hyperplasia or lobular carcinoma in situ, also increases the risk of developing breast cancer.

Estrogen exposure and hormone treatments

Extended exposure to estrogen and progesterone may increase the risk of breast cancer. This exposure could involve starting periods early or entering menopause late.

Some research associates hormone replacement therapy (HRT), specifically estrogen-progesterone therapy, with an increased risk of breast cancer.

The National Cancer Institute (NCI) also highlights studies suggesting that oral contraceptives may slightly increase the risk of breast cancer. However, this risk declined after stopping the use of oral contraceptives.


Although some research suggests breast cancer rates are highest in the non-Hispanic white population, the Centers for Disease Control and Prevention (CDC) states breast cancer mortality is higher among Black females than white females.

According to a 2021 study, Black females may be more susceptible to developing aggressive breast tumors.

Other research points out that other factors, such as socioeconomic disparities, contribute to racial differences in treatment options and cancer mortality.

For example, a 2020 study suggests difficulty accessing quality health insurance may contribute to late breast cancer diagnoses among people from marginalized groups.

Even with treatment, people are less likely to have a positive outcome when doctors diagnose breast cancer at a late stage.

Other risk factors

The following factors may also increase the risk of breast cancer:

  • Obesity: Obesity after menopause may contribute to a greater likelihood of developing breast cancer, possibly due to increased estrogen levels.
  • Regular alcohol consumption: According to the NCI, studies consistently find that females who consume alcohol have a higher risk of breast cancer than those who do not.
  • Dense breast tissue: Dense breast tissue is a risk factor for breast cancer.
  • Radiation therapy: Undergoing mantle field irradiation treatment for a different cancer may increase the risk of developing breast cancer later in life.

Learn more about dense breast tissue.

Cosmetic implants and breast cancer survival

Some research in a 2023 systematic review associates certain rare cancers, such as lymphoma or squamous cell carcinoma, with breast implants.

However, the review highlights that experts generally consider breast augmentation to be safe. Other research had the following findings:

  • A 2015 meta-analysis of 17 studies that included participants who had undergone cosmetic breast augmentation found no increased risk of breast cancer associated with the procedure. The incidence among these participants was lower than expected.
  • Research from 2021 suggests females with cosmetic implants have significantly lower rates of breast cancer than those without.
  • A 2020 study into the risk of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) in 3,546 people with macro-textured breast implants found the overall BIA-ALCL risk was higher than previous literature stated. The authors highlight the need for further evaluation.

Learn more about breast implants and cancer.

A doctor may diagnose breast cancer during routine screening or when a person reports symptoms. The following tests and procedures can help with a diagnosis:

Breast exams

This involves checking the breasts for lumps and other possible indications of cancer.

During the examination, the person may need to sit or stand with their arms in different positions, such as above their head or by their sides.

Imaging tests

The following scans may help detect breast cancer:

  • Mammogram: Doctors commonly use this type of X-ray during initial breast cancer screening. It produces images that can show lumps or irregularities.
  • Ultrasound: This scan helps a doctor evaluate the size and consistency of a lump. It may help differentiate between a solid mass and a fluid-filled cyst.
  • MRI: This combines different images to help doctors identify cancer or other irregularities. A doctor may recommend an MRI as a follow-up to a mammogram or ultrasound.


A biopsy involves extracting a tissue sample and sending it to a laboratory for analysis. The results can show:

  • if cells are cancerous
  • the type of cancer, if present
  • whether the cancer is hormone-sensitive

The doctor then stages the cancer using information such as the tumor size and how far the cancer has spread. This can provide information about the person’s outlook and the best course of treatment.

Further resources

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Treatment may depend on:

  • the type and stage of the cancer
  • the tumor’s sensitivity to hormones
  • the person’s age, overall health, and preferences

Cancer treatments can have adverse side effects. Before deciding on a treatment, people can discuss the potential risks with a doctor.

Treatment options include the following:


If surgery is necessary, the type will depend on the diagnosis and the person’s preferences. Types include:

  • Lumpectomy: A lumpectomy involves removing the tumor and a small amount of healthy tissue around it. It may be an option if the tumor is small and easy to separate from surrounding tissue.
  • Mastectomy: A mastectomy involves removing the breast’s lobules, ducts, fatty tissue, nipple, areola, and some skin. In some types, a surgeon also removes the lymph nodes.
  • Sentinel node biopsy: This procedure involves the removal of lymph nodes to help doctors see how far cancer has spread and decide the best treatment.
  • Axillary lymph node dissection: If a doctor finds cancer cells in the sentinel nodes, they may recommend removing additional lymph nodes in the armpit with an axillary lymph node dissection.

Following a mastectomy, a surgeon can reconstruct the breast so that it looks more natural. This can help a person cope with the psychological effects of breast removal.

The surgeon can reconstruct the breast during the mastectomy or at a later date. They may use a breast implant or tissue from another body part.

Learn about breast reconstruction surgery.

Radiation therapy

A person may undergo radiation therapy during or after surgery. It is most common following a lumpectomy, but some people may require radiation after a mastectomy.

This therapy involves targeting the tumor with controlled doses of radiation that kill any remaining cancer cells.

Learn more about radiation therapy.


A doctor may prescribe chemotherapy if there is a high risk of recurrence or spread. Chemotherapy after surgery is called adjuvant chemotherapy.

A doctor may recommend chemotherapy before surgery to shrink the tumor and make it easier to remove. This is called neoadjuvant chemotherapy.

Hormone-blocking therapy

Hormone-blocking therapy may help treat estrogen receptor-positive and progesterone receptor-positive cancers. Healthcare professionals may administer it after surgery to prevent recurrence or beforehand to shrink the tumor.

Hormone-blocking therapy may be an option for people who cannot have surgery, chemotherapy, or radiotherapy.

Examples of hormone-blocking medications may include:

Learn more about hormone therapy for breast cancer.

Biological treatment

Targeted drugs, such as trastuzumab (Herceptin) and lapatinib (Tykerb), can destroy specific types of breast cancer.

There is no way to prevent breast cancer. However, the following steps may help reduce the risk:

Preventive surgery may also be an option for people with a high breast cancer risk.

The Bezzy Breast Cancer app provides access to an online breast cancer community where users can connect with others and gain advice and support through group discussions.

Learn more about breast cancer prevention.

Breast cancer screening

Multiple different guidelines for screening exist. The following are some recommendations for females with an average risk of breast cancer:

United States Preventive Services Task Force, 2024• Ages 40 to 74: Have screenings every 2 years.
ACS, 2023• Ages 40 to 45: Have screenings every year if they wish.
• Ages 45 to 54: Have screenings every year.
• Ages 55 years and older: Have screenings every year or 2 years.
American College of Physicians, 2019• Ages 40 to 49 years: Discuss the benefits and risks of regular screenings with a doctor.
• Ages 50 to 74: Have screenings every 2 years.
• Ages 75 or older: Continue with screenings if they have a life expectancy of 10 or more years.

Despite the slight variations, most experts recommend at least speaking with a doctor about breast cancer screening from the age of 40 onward.

People can speak with their doctor about breast screening guidelines and create a screening plan that works for their circumstances.

According to a 2019 article, breast cancer death rates declined by around 40% between 1989 and 2017. However, a 2019 study suggested the rate in the United States may no longer be declining among females ages 20 to 39 years.

A survival rate describes how long a person with breast cancer is likely to live after diagnosis compared with someone who does not have the condition.

The NCI currently estimates that about 91% of females with breast cancer will survive for at least five years after diagnosis.

It is important to remember that researchers use survival rates to assess large populations. In calculating this rate, they exclude the risk of dying from other causes.

A survival rate cannot predict a specific individual’s outlook.

Learn more about breast cancer survival statistics.

Is breast cancer painful?

A lump or a mass in the breast is the most common symptom of breast cancer. These lumps are usually painless. However, a person may experience pain in the nipple or breast area that appears connected to their menstrual cycle.

Anyone who experiences breast pain, especially if it is severe or persistent, should consult a healthcare professional.

How long can someone have breast cancer without knowing?

How long a person has breast cancer without knowing may depend on the type of breast cancer, their symptoms, and screenings.

For example, inflammatory breast cancer is a rare, aggressive type of breast cancer that does not usually cause a lump and may not show on a mammogram. Diagnosis may only occur when symptoms appear during advanced stages.

What is the life expectancy for someone with breast cancer?

According to research, around 91% of females with breast cancer will survive for at least five years following a diagnosis. However, the ACS suggests the outlook for a person who receives a diagnosis now may be better than this due to old data and constant improvements in treatment.

Breast cancer may cause symptoms such as a lump, pain, or skin changes to the breast or nipple. Anyone with a breast lump should see a healthcare professional.

Treatment options may include chemotherapy, radiation, or surgery. The most appropriate treatment may depend on the cancer type and stage.

A person can take steps to reduce their risk of breast cancer, such as maintaining a healthy lifestyle and speaking with their doctor about the best pace of screening.

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