Breast Cancer, from the CureRays guide library.

Breast cancer begins when cells in the breast's ducts or lobules grow out of control; caught early, it is highly treatable.

What it is.

The breast is made of ducts that carry milk and lobules that make it. Breast cancer starts when cells lining these structures grow uncontrollably, forming a lump that can invade nearby tissue and, over time, spread elsewhere. Found early, the 5-year survival rate is about 99%.

How radiation treats it.

Radiation uses focused high-energy x-rays to damage cancer-cell DNA so the cells can no longer divide. Healthy cells repair this damage better than cancer cells, so fractionated treatment clears cancer while sparing normal tissue. Sessions are painless and brief; the main side effects are a sunburn-like skin reaction and some fatigue that settle after treatment.

The ways we can treat it.

Whole-breast irradiation (WBI). Treats the whole breast after lumpectomy. Standard today is hypofractionation — slightly larger daily doses over ~3 weeks (e.g., 40 Gy in 15 fractions).

Accelerated partial-breast irradiation (APBI). Targets only the area around the tumor bed for select early cancers, over 1-2 weeks, with fewer side effects.

Advanced external-beam (IMRT/IGRT/breath-hold). Shapes and aims the dose precisely; breath-hold moves the heart away for left-sided cancers.

Questions we hear often.

Will radiation make me radioactive? No. External-beam radiation passes through and leaves no radioactivity. You are safe around family, including children.

How many treatments will I need? Often 15-20 short daily sessions over about 3 weeks, and sometimes fewer with partial-breast approaches.

Can I keep working? Most people continue normal activities, fitting brief daily visits around their day.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.