Overview
Breast cancer begins when cells in the breast grow abnormally and form a lump or thickening. WHO reports 2.4 million diagnoses worldwide in 2024, making it the commonest cancer in women in most countries.
Most breast lumps are not cancer. The reason to check any new lump promptly is that when it is cancer, finding it early changes the outcome profoundly. WHO reports five-year survival above 90% in high-income countries, and 40% in South Africa, a gap driven by how late the diagnosis is made and what treatment is available.
Disease Summary
- Category
- Non-Communicable Disease
- Cause
- Abnormal growth of cells in breast tissue
- Transmission
- Not transmissible
- Body System
- Reproductive System
- Preventable
- No
- Curable
- Yes
Symptoms
Common Symptoms
Knowing how your breasts normally look and feel is what allows you to notice a change. Any of the following is a reason to be seen.
A New Lump or Thickening
In the breast or the armpit. It is often painless, which is precisely why it should not be dismissed.
A Change in Size or Shape
One breast becoming noticeably different from the other, or from how it was.
Dimpling or Puckering of the Skin
Skin that looks pulled in, or has the texture of orange peel.
Discharge From the Nipple
Particularly if it is bloody, from one breast only, and occurs without squeezing.
A Nipple That Has Turned Inwards
A new change in the nipple, including it pulling inwards or changing position.
Redness, Warmth or a Rash on the Breast
Particularly if it does not settle, since this can indicate an uncommon but fast-moving form.
Persistent Pain in One Area
Breast pain is usually not cancer, but pain in one fixed spot that does not vary with the cycle deserves checking.
Swelling in the Armpit or Around the Collarbone
Swollen glands in these areas can be the first sign noticed.
Danger Signs
Seek urgent medical attention immediately if any of the following symptoms develop.
A Hard, Fixed Lump That Does Not Move
A lump that feels tethered to the skin or the chest wall needs urgent assessment.
A Red, Hot, Swollen Breast That Does Not Settle
Particularly outside breastfeeding, or where antibiotics have not helped. This needs urgent review.
Skin Changes or an Ulcer on the Breast
Any breakdown of the skin over a lump requires urgent assessment.
Bloody Discharge From One Nipple
Spontaneous bloody discharge from a single duct needs investigating.
New Persistent Bone Pain, Breathlessness or Weight Loss
In someone with a breast lump or a previous breast cancer, these need urgent assessment.
Diagnosis
Breast Awareness and Prompt Presentation
WHO’s early diagnosis strategy rests on people being aware of the signs and seeking advice for abnormal findings, followed by timely evaluation and referral.
Clinical Examination
Examination of both breasts and the armpits by a clinician, which establishes what needs further investigation.
Imaging
Mammography, which CDC describes as an x-ray of the breast, and ultrasound, which is often more useful in younger women whose breast tissue is denser.
Biopsy
A sample of the lump is taken with a needle and examined. This is the only way to establish whether a lump is cancer.
Establishing the Type and Stage
Testing the sample establishes the type of cancer and whether it responds to hormone or targeted treatment, which shapes the whole treatment plan.
Laboratory Tests
Mammogram
The test used for screening and for assessing a lump in older women. CDC describes it simply as an x-ray of the breast.
Breast Ultrasound
Often more useful than mammography in younger women, and used to guide a biopsy needle accurately.
Needle Biopsy
The test that confirms or excludes cancer. Everything else points towards the diagnosis, this establishes it.
Receptor Testing on the Biopsy Sample
Establishes whether the cancer responds to hormone-blocking or targeted treatment, which makes a substantial difference to what can be offered.
Staging Scans
Establish whether the cancer has spread, which determines the treatment plan.
Treatment
Surgery
Either removal of the lump with a margin of tissue, or removal of the breast. The choice depends on the size and type of the cancer and on the woman’s preference.
Radiotherapy
Uses high-energy rays to destroy any remaining cancer cells, usually after surgery that conserves the breast.
Hormone Treatment
For cancers that respond to hormones. These tablets substantially reduce the chance of the cancer returning, and they are taken for years rather than weeks.
Chemotherapy and Targeted Treatment
Medicines that kill cancer cells or block the specific signals a particular cancer depends on. Which are used depends on the receptor testing done on the biopsy.
Supportive and Palliative Care
Pain control, management of side effects, and psychological and practical support run alongside cancer treatment rather than replacing it.
Prevention
Know your breasts and act on changes
WHO’s strategy places awareness of signs and symptoms and timely presentation at the centre, because most breast cancers are found by the woman herself.
Attend screening where it is offered
WHO describes screening as mammography in apparently healthy women, usually aged 50 to 69. National programmes vary, so follow the one where you live.
Limit alcohol
WHO names harmful use of alcohol among the modifiable risk factors, and CDC states risk rises with the amount consumed.
Stay physically active and maintain a healthy weight
CDC lists physical inactivity and being overweight after the menopause among the risk factors that can be changed.
Breastfeed where you can
CDC lists not breastfeeding among the factors associated with higher risk.
Avoid tobacco
WHO lists tobacco use among the risk factors for breast cancer.
Risk Factors
Women Over 40
WHO states that breast cancer occurs at any age after puberty, with rates increasing in later life.
- CDC states that most breast cancers are diagnosed after age 50
- Risk increases steadily with age
- WHO reports that 80% of cases occur in women with no modifiable risk factor other than being female and over 40
- This is the group most screening programmes are designed around
Women With a Family History or Inherited Gene Change
A minority of breast cancers run in families, and these need different management.
- A mother, sister or daughter diagnosed with breast cancer, particularly when young
- Several relatives on the same side of the family affected
- A known inherited gene change in the family
- These women may be offered earlier or more frequent screening
Women With Modifiable Risk Factors
These raise risk but account for a minority of cases.
- Regular alcohol consumption
- Being overweight after the menopause
- Physical inactivity
- Some hormone treatments used for several years after the menopause
Women Without Access to Early Diagnosis
This is the factor that most affects survival rather than incidence.
- Women in settings where a lump cannot be assessed quickly
- WHO reports five-year survival of 40% in South Africa against over 90% in high-income countries
- Late presentation is the main driver of that gap
- WHO notes that breast cancer mortality fell 40% in high-income countries between the 1980s and 2020, a fall not matched in low-income settings
Complications
Spread to the Lymph Nodes
Spread to the glands in the armpit is common and affects both the treatment plan and the outlook.
Spread to Bones, Liver, Lungs or Brain
Breast cancer that has spread is treatable and controllable, often for years, though not usually curable.
Arm Swelling After Treatment
Removal of lymph nodes or radiotherapy can cause persistent arm swelling, which is manageable with specialist support.
Side Effects of Treatment
Fatigue, early menopause, effects on the heart and on bone strength all occur, and all are monitored for and managed.
Emotional and Psychological Impact
Anxiety, low mood and effects on body image, relationships and work are common and deserve support rather than endurance.
Recurrence
Breast cancer can return years later, which is why follow-up continues long after treatment ends.
When to Seek Medical Care
Any New Lump in the Breast or Armpit
Most are not cancer. Have it checked anyway, and quickly.
Any Change in the Skin or the Nipple
Dimpling, puckering, a rash, an ulcer, or a nipple that has newly turned inwards.
Bloody Discharge From One Nipple
Particularly if it happens without squeezing.
A Red, Hot, Swollen Breast That Does Not Settle
Especially outside breastfeeding, or where antibiotics have not worked.
For Screening When You Are Invited
Screening is for women with no symptoms at all, and that is precisely the point of it.
Prognosis
Early Breast Cancer Has a Good Outlook
Breast cancer found early and treated properly carries a high chance of cure.
The Survival Gap Between Countries Is Large
WHO reports five-year survival above 90% in high-income countries, 66% in India and 40% in South Africa. The difference is late diagnosis and access to treatment.
Treatment Often Continues for Years
Hormone treatment is typically taken for 5 to 10 years, long after the visible treatment has finished.
Advanced Disease Is Treatable
Breast cancer that has spread can often be controlled for years with treatment, even where cure is not the goal.
Differential Diagnosis
Benign Breast Lumps
Fibroadenomas and cysts are common, especially in younger women, and feel like lumps. Only assessment can tell them apart.
Breast Infection
Causes a red, hot, painful breast, usually during breastfeeding. It responds to antibiotics, and a breast that does not respond needs further assessment.
Cyclical Breast Pain
Pain and lumpiness that varies with the menstrual cycle is common and is not cancer, but a fixed lump within it still needs checking.
Blocked Milk Ducts
Cause a tender lump during breastfeeding that settles with feeding and massage.
Swollen Glands From Infection
Armpit swelling can follow an infection elsewhere, and is separated by examination and the course over time.
References
World Health Organization: Breast cancer
WHO fact sheet on burden, risk factors, symptoms, early detection and treatment.
World Health Organization: Global Breast Cancer Initiative
WHO’s strategy for early detection and treatment, and the survival gap between countries.
CDC: Breast Cancer Symptoms
The changes to look for and when to see a health worker.
CDC: Screening for Breast Cancer
What screening involves, who it is for and the place of other tests.
Frequently Asked Questions
Does a breast lump mean cancer?
Usually not. Most breast lumps are benign, particularly in younger women. That is a reason to have a lump checked without fear rather than a reason to delay, because when a lump is cancer, finding it early changes the outcome substantially.
What should I be looking for?
A new lump or thickening in the breast or armpit, a change in size or shape, dimpling or puckering of the skin, a nipple that has newly turned inwards, discharge from the nipple, or redness or a rash that does not settle. Knowing how your breasts normally feel is what makes a change noticeable.
At what age should screening start?
WHO describes screening as mammography in apparently healthy women, usually aged 50 to 69. CDC, following United States guidance, describes mammography every two years for women aged 40 to 74 at average risk. National programmes differ, so follow the one where you live and ask if you have a family history.
Can breast cancer be prevented?
Only partly. WHO states that approximately 80% of breast cancers develop in women with no modifiable risk factor other than being female and over 40. Limiting alcohol, staying active, maintaining a healthy weight and breastfeeding all reduce risk, but early detection matters more than prevention alone.
Why do survival rates differ so much between countries?
Because of how late the cancer is found and what treatment is available. WHO reports five-year survival above 90% in high-income countries, 66% in India and 40% in South Africa. The biology of the disease is not what differs.