Space 01 · Understand

What is breast cancer?

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Chapter 01 · What is breast cancer?
THE QUESTION

Is a lump in the breast always cancer?

The answer in a few cards.

1 / 7

What is the breast?

The breast contains glands that make milk (the lobules), ducts that carry it to the nipple, fat and , especially under the arm.

Source: NCI, 2026

2 / 7

When cells get out of control

Our body constantly renews its cells. Sometimes cells multiply without control and form a mass: a tumour.

Source: NCI, 2026

3 / 7

Benign or malignant?

A tumour is not cancer: it does not spread. Most breast lumps are not cancer (cysts, fibroadenomas…). But only a test can tell.

Source: ACS, 2026

4 / 7

Where does it start?

Most often in the milk ducts: this is . At the CNO in Nouakchott, it accounts for 85% of the cases studied.

Source: ACS, 2026 · PAMJ, 2025

5 / 7

In situ or invasive

“”: the cancer stays inside the duct. “”: it has gone through the duct wall and can reach the tissue around it.

Source: ACS, 2026

6 / 7

It can travel

Without treatment, cells can move to the , then to the bones, liver, lungs or brain. These are called .

Source: NCI, 2026

7 / 7

The most common cancer in women

In Mauritania, it is the most common cancer in women. Worldwide, 2.3 million new cases were recorded in 2022.

Source: PAMJ, 2025 · WHO, 2024

DID YOU KNOW?

Worldwide, on average 1 woman in 20 will develop breast cancer during her lifetime.

Source: IARC, 2025

TRUE OR FALSE?

“A lump in the breast is always cancer.”

TRUE OR FALSE?

“Breast cancer can also affect men.”

KEY POINTS
  • Breast cancer starts when breast cells multiply without control.
  • Most lumps are not cancer, but you should always get checked.
  • It is the most common cancer in women in Mauritania.
SOURCES FOR THIS CHAPTER

Information based on publications by the WHO, the International Agency for Research on Cancer (IARC), the French National Cancer Institute, the American Cancer Society, the National Cancer Institute, Cancer Research UK and published scientific studies. The information on ROSE does not replace the advice of a health professional.

Chapter complete!

You now know more than many people. Pass it on.

Next chapter: The signs →
Sources: NCI, 2026 · ACS, 2026…

15 stories to understand it all

Pick a question and let the cards guide you.

01In progressWhat is breast cancer?Is a lump in the breast always cancer?5 min read02To readThe signsWould you recognise breast cancer?5 min read03To readRisk factorsWhy do some people get breast cancer and others don't?5 min read04To readScreening, by country and ageShould you wait for a sign before getting a test?5 min read05To readDiagnosis and testsThey found a lump: what happens next?5 min read06To readTypes: hormone-sensitive, HER2, triple-negativeAre all breast cancers the same?5 min read07To readStagesWhat does “stage 2” mean?5 min read08To readTreatmentsHow is breast cancer treated?5 min read09To readLiving with treatment side effectsFatigue, hair, morale: how to get through treatment?5 min read10To readLife afterAnd when treatment is over?5 min read11To readGenetics and BRCAIs breast cancer passed down in families?5 min read12To readBreast cancer in menCan a man get breast cancer?5 min read13To readYoung womenI'm under 40: can it happen to me?5 min read14To readSupporting a loved oneHow can you help someone with breast cancer?5 min read15To readPreventionCan you reduce your risk of breast cancer?5 min read

Information based on publications by the WHO, the International Agency for Research on Cancer (IARC), the French National Cancer Institute, the American Cancer Society, the National Cancer Institute, Cancer Research UK and published scientific studies. The information on ROSE does not replace the advice of a health professional.