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Radiation Therapy for Breast Cancer: How It Works and What to Expect
By Prashant Baghel
Getting diagnosed with breast cancer can feel scary and confusing. There are many treatments, and one of the most helpful is radiation therapy for breast cancer. This treatment helps lower the chance of the cancer coming back by killing any cancer cells left behind after surgery.
But what exactly is radiation therapy? How does it work? And what should you expect during the process? In this article, we’ll explain everything in simple words, so you can feel more prepared and less worried about what’s coming next.
What Does Radiation Therapy Do?
Radiation therapy, also called radiotherapy, uses high-energy beams, like X-rays or particles, to damage the DNA in cancer cells. When DNA is too damaged to fix, cancer cells die or stop dividing. Normal cells can be affected too, but cancer cells are more likely to be affected because they grow faster.
After surgery (lumpectomy or mastectomy) for breast cancer, radiation is often used to kill any cancer cells that might still be in the breast, chest wall, or nearby lymph nodes. It can also be used before surgery to shrink a tumor or to ease symptoms when cancer has spread.
Why Use Radiation Therapy for Breast Cancer?
Here are the main reasons doctors say you should do it:
Lower risk of recurrence: Radiation lowers the risk of cancer coming back to the same breast after breast-conserving surgery (lumpectomy).
Improved survival: Many studies have shown that adding radiation to surgery can help people live longer by stopping local relapse.
After mastectomy: After a mastectomy, radiation may be used on the chest wall and nearby lymph nodes if the tumor was big, affected the skin, chest wall, or a lot of lymph nodes.
Target lymph nodes: Radiation can treat lymph nodes that have cancer in them, such as those under the arm, above the clavicle, or in the internal mammary.
Palliative use: In advanced cases, radiation can help reduce pain, stop bleeding, or stop metastases (for example, in the brain or bones).
Types and Techniques of Radiation Therapy for Breast Cancer
There are a few different ways to give radiation for breast cancer, depending on the patient, the tumor's location, and the risk zones.
External Beam Radiation Therapy (EBRT): This is the most common type. A machine outside the body sends beams to the breast, chest wall, and sometimes lymph nodes.
Whole-breast irradiation: Radiation is given to the whole breast after a lumpectomy.
Boost: A concentrated ("boost") dose may be given to the tumor bed, which is the area where the tumor was removed, to improve local control.
Regional nodal radiation: If nodes were involved, radiation may reach the axilla (underarm), supraclavicular, or internal mammary nodes.
Modern EBRT techniques include:
3D conformal radiotherapy (3D-CRT): Uses 3D imaging to shape the beams to the breast anatomy.
Intensity-modulated radiation therapy (IMRT): Modulates beam strength so higher doses go where needed and lower doses to healthy tissue.
Proton therapy (in select centers): It uses protons instead of X-rays to lower the amount of radiation that reaches nearby organs like the heart and lungs.
Deep Inspiration Breath Hold (DIBH): Patients hold their breath to move their heart away from the radiation field, which is especially helpful for left-side breast cancers.
Internal radiation therapy (brachytherapy)
A radioactive source is put inside or near the tissue where the cancer was removed (tumor bed) during brachytherapy. It sends radiation from inside instead of from outside. For certain patients, this method is sometimes used as "accelerated partial breast irradiation." It can cut down on the total time of treatment and save more healthy tissue.
These are some types:
Intracavitary brachytherapy: The radiation source is put into a space left over from a lumpectomy.
Interstitial brachytherapy: Several small radioactive tubes (catheters) are put into the breast tissue around the tumor.
Brachytherapy can be used on its own or as an extra treatment with external beam radiation.
What Happens Before the First Radiation Session: Treatment Planning
Before treatment starts, a number of steps are taken to make sure everything is safe and correct.
Talking to a radiation oncologist
The doctor looks over your surgery, pathology, imaging, and past treatments. They choose the areas that need radiation (breast, chest wall, nodes) and how much radiation is needed.
Scans for planning and simulation
To map out your body, you get a CT scan of your chest (and sometimes your breast in position. In each session, skin marks or tattoos may be used to help with alignment. You can also use a mold or "vac-lock" to keep the body still.
Calculating the dose and arranging the beams
Radiation physicists and dosimetrists figure out how much radiation each beam will give off, making sure not to hurt organs like the heart and lungs.
Check / dry run
Before treatment begins, a "mock treatment" or verification run is sometimes done to check the position and beam angles.
What to Expect When You Get Radiation Treatment
Length & Schedule
- Most of the time, treatment is given once a day, Monday through Friday.
- Depending on the protocol (longer traditional schedules or shorter hypofractionated ones), a full course may last anywhere from 3 to 6 weeks.
- Some protocols only need five days for certain early-stage cases.
- The actual radiation beam is delivered in minutes or less, but each session usually lasts 10 to 40 minutes.
What Happens During a Session
- You will lie on a treatment table in the same position that was planned during the simulation.
- Skin marks and immobilization devices help make sure things are right.
- Machines will send radiation beams from different angles to focus the dose where it is needed.
- The process doesn't hurt; you won't feel the radiation itself, but the position might be uncomfortable.
Doses of Boost
After radiation to the whole breast or chest wall is done, a boost may be given to the tumor bed to help keep it under control. This may require more sessions (for example, 4 to 5 more days), but it is focused on a small area.
What to Expect in the Short and Long Term with Side Effects
Short-Term (During and Right After Treatment)
- Skin reactions: redness, irritation, peeling, and effects that look like sunburn in the area that was treated.
- Breast swelling and tenderness: The breast that was treated may feel heavier or sore.
- Fatigue: Many patients feel more tired as time goes on.
- Darkening of the skin: The skin may temporarily darken or change texture.
- Breast firmness: Some parts may get a little firmer or swell up.
These effects usually get worse near the end of radiation and then get better over weeks to months.
Long-Term (Months to Years Later)
- Changes in the size or shape of the breasts: Radiation can make things smaller, firmer, or uneven.
- Fibrosis or scarring: The tissues underneath may form scar tissue that makes them stiff or a little.
- Risk to the heart or lungs: There is a small chance of damage to the heart or lungs in the long run, especially with radiation on the left side. The goal of modern planning is to reduce this.
- Lymphedema: If lymph nodes were exposed to radiation, the arm or chest wall may swell.
Conclusion
Radiation therapy is a key part of treating breast cancer. It helps kill any remaining cancer cells, lowers the risk of recurrence, and makes outcomes better. Even though there are side effects and long-term risks, new methods make the process safer and more accurate than ever.
Radiation therapy may be an important part of the plan for you or someone you know who has breast cancer. You deserve a care center that uses advanced planning, skilled staff, and personalized care to make sure you get the best balance of safety and benefit.
Frequently Asked Questions
No, you won't feel the beams themselves. The only pain comes from lying still or having mild skin irritation.
It can make reconstruction harder, especially with implants. Experts need to carefully plan the timing and technique.
Some patients with low risk might not need it, but the type, size, margins, age, and risk of the tumor all play a role in the decision. Your oncologist will tell you what to do.
Changes in the skin usually start after a week or two of treatment. Fatigue usually builds up slowly.
During treatment, many patients go back to doing normal things. After finishing, take a break for a few weeks. It may take months to get all your energy back.