Radiation therapy is a common and highly effective treatment for breast cancer. It uses high-energy radiation to target and destroy cancer cells. But the side effects of radiation for breast cancer can be uncomfortable and impact your daily life during and after treatment.

As an oncology physical therapist, I often help people recover after breast radiation therapy, so here’s what to expect and what you can do to manage these side effects.

What Is Radiation Therapy for Breast Cancer?

Radiation therapy is one of the most effective ways to treat breast cancer. Research shows that it significantly reduces the risk of cancer coming back.

High-energy rays damage the DNA of cancer cells, stopping them from growing and dividing.

Your radiation oncologist can deliver this treatment in two ways: externally with a machine that directs beams at the affected area (external beam radiation therapy), or internally by placing radioactive implants near the tumor (brachytherapy).

An advanced type of external beam radiation is intensity modulated radiation therapy (IMRT). This technique allows your radiation oncologist to shape the radiation beams more precisely to match your tumor, delivering higher doses to cancer cells but minimizing exposure to surrounding healthy tissue.

Most often, you’ll have radiation after surgery to destroy any remaining cancer cells. 

That said, sometimes it’s also used before breast cancer surgery to shrink tumors and improve surgical outcomes.

Common Anxieties with Breast Radiotherapy

Many people feel anxious before starting radiation therapy. It’s completely normal to feel worried and have questions. Most of my patients have similar concerns, so let’s address them.

First, undergoing radiation therapy doesn’t make you radioactive.

You won’t pose any risk to your family, friends, or pets. The radiation is targeted only to the treatment area, so it’s safe for everyone around you. That said, you should avoid getting pregnant during radiation therapy because of potential risks to a developing baby.

Many breast cancer patients worry about the side effects of radiation therapy.

It’s true that you’ll likely experience things like fatigue, skin irritation, or changes in appetite, but these effects are usually temporary.

There are some long-term side effects and risks, but as a physical therapist who specializes in oncology, I can tell you that there are steps you can take to manage them.

If you want to be better prepared for the side effects of radiation for breast cancer or are already dealing with the symptoms and want to improve them, you can find a lot of practical education and guidance in my program, Breast Cancer Rehab.

What Are the Side Effects of Radiation for Breast Cancer?

Radiation therapy is one of the best ways to treat breast cancer, but, unfortunately, it comes with unpleasant side effects. The good news is that many of them are short-term and will go away gradually after you finish treatment.

Short-term side effects like fatigue, skin irritation, and breast swelling are challenging while you’re going through them, but they’re manageable and temporary.

Long-term side effects are fewer, but some issues can stick around or show up months or even years after treatment ends. Their severity often depends on how much radiation you receive and which techniques your oncologist uses.

Someone with early-stage breast cancer typically needs a lower radiation dose than someone with advanced cancer, which usually means fewer long-term effects.

There’s plenty of information about how radiation works, but practical guidance on managing side effects is much harder to find. Most people are told that these side effects exist, but are given little information on what to do about them.

By 2030, over 4 million breast cancer survivors will have been treated with radiation therapy. That’s millions of people who need to know how to manage these side effects, especially the long-term ones.

As an oncology physical therapist, I’ve seen firsthand that early intervention makes a huge difference.

The sooner you address these effects, the better your quality of life will be. For example, you can try these exercises after breast cancer radiation.

Short-Term Side Effects of Radiation Therapy

1. Skin Irritation

Skin irritation is one of the most common side effects you’ll experience, especially on your breast skin where radiation is targeted. Your skin may become red, sensitive, and dry, similar to a sunburn. Some people also experience itching, peeling, or blistering.

These skin reactions are uncomfortable, but there are things you can do to help your skin heal faster:

• Wash the treated area gently with mild, fragrance-free soap and lukewarm water, and then pat it dry with a soft towel.
• Stay out of direct sunlight and extreme temperatures.
• Avoid tight clothing that rubs against your skin.
• Ask your healthcare team about over-the-counter creams or ointments that can ease symptoms.

These steps may seem simple and small, but taking them can make a big difference in how quickly your skin heals and how comfortable you feel during treatment.

2. Fatigue

Radiation therapy can make you feel exhausted during and after treatment sessions. This fatigue can make it hard to keep up with your normal routine, but it should start to improve once your treatment is complete.

Rest as much as you can while you’re going through radiation.

If you feel up to it, gentle exercise like walking or yoga can boost your energy levels. Eating balanced meals and limiting caffeine also helps fight fatigue.

3. Breast Swelling and Tenderness

Your breasts may become swollen and tender because of inflammation and fluid buildup in the treated area. This radiation therapy side effect can be very uncomfortable, but it should start to resolve after your last dose.

A well-fitted, supportive bra can help reduce movement and minimize pain and swelling.

Cool compresses on the affected area can also bring relief. Your radiation therapy team may also suggest taking over-the-counter pain relievers if needed as you receive radiation therapy.

4. Changes in Breast Appearance

Radiation therapy can temporarily change how your breasts look and feel.

You might notice skin discoloration, thickening of breast tissue, or changes in breast size or shape. The treated breast may feel firmer or denser, and the skin might look darker or more tanned.

Most of these changes resolve within a few weeks of finishing treatment, but sometimes they stick around longer.

Moisturizing regularly helps with dryness and tightness, and a well-fitted bra provides support as your breasts change. Gentle stretching exercises can improve flexibility and comfort in the affected area.

5. Hair Loss

Hair loss can happen as a side effect of breast cancer radiation therapy.

For many people, this is one of the most emotionally difficult side effects.

It doesn’t feel physically painful, but it can be very challenging to mentally cope with.

If hair loss affects your scalp, you should use mild shampoos and skip heat styling tools to protect the hair that remains. Soft hats, scarves, or wigs can also provide coverage if you want it.

6. Feeling Sick

Some people feel nauseated or generally unwell during radiation therapy. It’s important to remember that these symptoms are temporary, and you will feel healthy again.

Here are a few tips that can help you feel better during treatment:

• Eat small, frequent meals instead of large ones to keep nausea under control.
• Choose bland, easy-to-digest foods that are easier on your stomach.
• Try gentle activities like walking, deep breathing, and meditation.
• Ask your healthcare provider about anti-nausea medications if symptoms persist.

Nausea and the general feeling of being unwell should go away gradually after your treatment plan is complete.

Learn more about how to reduce the side effects of radiation therapy.

Long-Term Side Effects of Radiation for Breast Cancer

1. Breast Changes

You may experience long-term breast changes after radiation exposure.

Over time, your breast tissue may become firmer and denser because of radiation fibrosis, which is a process where connective tissue thickens and hardens.

This can make your breast feel heavy or uncomfortable and may change its symmetry and shape. The skin in the treated area might also show permanent discoloration or have a leathery texture.

However, you can take steps to minimize these changes:

• Moisturize regularly with gentle, fragrance-free skincare products.
• Do targeted stretches and exercises to maintain tissue flexibility.
• Start early, because the sooner you begin, the better your results.

These changes can affect how you feel about your body, but it’s possible to minimize them over time with physical therapy. Start with these exercises:

2. Skin Changes

After radiation therapy, you may experience chronic skin changes like persistent dryness, increased sensitivity, and thickening in the treated area.

Your skin may develop a darker, more pigmented tone compared to surrounding areas and become more prone to irritation and injury.

To manage these skin changes long-term, you should:

• Use mild, fragrance-free moisturizers daily.
• Protect the treated area from sun exposure.
• Be gentle when washing and drying your skin.

Over time, your skin reactions will get less intense with consistent daily care.

3. Lymphedema

Radiation therapy raises your lifelong risk of developing lymphedema.

It’s a chronic condition that causes swelling in your arm, hand, or chest because of lymph fluid buildup. Your risk is higher if your lymph nodes were affected during the radiation treatment.

Physical therapy and staying active in general can help prevent lymphedema and lower your risk of developing the condition. 

It’s important to do exercises that support lymphatic drainage, which keeps fluid moving properly through your body, such as walking, swimming, or using vibration plates and rebounders at home.

Manual lymphatic drainage (a gentle massage technique that encourages lymph fluid to flow in the right direction) can also be part of your prevention routine. 

Here are a few helpful guides you can follow:

It’s important to watch for early signs like heaviness, tightness, or subtle swelling because lymphedema is much easier to manage in its early stages.

When caught early, it’s sometimes even possible to reverse the swelling completely.

4. Cardiovascular Complications

Radiation therapy can have long-term effects on your cardiovascular system and increase the risk of heart disease and other cardiac complications.

Living a heart-healthy lifestyle, such as eating well and staying active, helps reduce your risk.

It’s also important to schedule regular cardiac screenings with your doctor.

Your healthcare team may have more specific suggestions for how to manage your cardiovascular risk and the important things to pay attention to, depending on your treatment plan. 

Learn more about the 5 things they never tell you about life after cancer.

5. Loss of Range of Motion and Tightness

Radiation therapy can affect your muscle tissue and tendons. 

Radiation fibrosis can build up in and around these tissues, causing them to lose elasticity. This leads to tightness and reduced range of motion. For example, you might struggle to reach high cupboards or clasp your bra. 

Shoulder pain after breast cancer is another common problem I see as an oncology physical therapist.

Physical therapy is the best way to improve your range of motion and reduce tightness after breast cancer treatment.

You can find many exercises to help you build up strength and flexibility in Breast Cancer Rehab, but here are a few simple guides to help you get started:

Side Effects of 5-Day Radiation for Breast Cancer

5-day radiation therapy delivers higher doses over just 5 days instead of multiple weeks.

This can be more convenient, but the higher doses may also cause more intense side effects compared to conventional radiation therapy.

You can expect short-term effects like skin irritation, fatigue, and breast swelling, which should improve once the treatment is complete. However, they can be quite intense during the treatment.

Similar to conventional radiation therapy, long-term side effects may include skin and breast changes, along with a risk of lymphedema. It’s possible to manage and improve all of them with physical therapy.

Side Effects of Radiation for Breast Cancer After Lumpectomy

After a lumpectomy, you’ll likely need radiation therapy to target any remaining cancer cells in your breast and reduce the risk of recurrence.

Once treatment begins, you may experience common side effects like skin irritation, fatigue, and breast swelling. Your skin may become red, dry, and sensitive.

These side effects should subside once your treatment ends, but some changes in your skin and breast appearance may stick around.

Radiation therapy also increases your risk of developing lymphedema later in your life.

That said, you can manage and improve all of these side effects of radiation for breast cancer with consistent physical therapy. It’s one of the most important parts of breast cancer rehabilitation.

Do You Ever Fully Recover from Radiation Therapy?

Unfortunately, radiation therapy for breast cancer often comes with unpleasant side effects, and some of them can stay with you long-term. However, most of them are manageable with proper care and physical therapy.

Short-term side effects like fatigue and skin irritation typically resolve on their own after treatment ends, so you should fully recover from them over time.

Long-term side effects of radiation therapy, such as radiation fibrosis, limited range of motion, and lymphedema, are where consistent physical therapy makes the biggest difference.

As an oncology physical therapist, I, unfortunately, often see people years after their radiation therapy who are still struggling with long-term side effects. They often tell me that they assumed they just had to live with the tightness, swelling, or limited movement.

Many didn’t know that physical therapy could help, or they weren’t given resources on how to manage these effects.

Physical therapy can help a lot, even if it has been years since your treatment. You can manage side effects like struggling to lift your arm overhead or experiencing tightness in your chest and shoulder with exercises and manual therapy.

I want to make physical therapy more accessible to everyone who needs it, so I turned my knowledge as an oncology PT into an online program, Breast Cancer Rehab.

It has a dedicated module on how to recover from radiation therapy and manage side effects, even if you’ve been experiencing them for a long time.

FAQs

What to expect from radiation therapy for breast cancer?

After you finish radiation treatment, your body needs time to recover. Short-term side effects like skin irritation, fatigue, and breast swelling may stick around for a few weeks, but they typically improve as your body heals. Some changes in your skin and breast appearance can become long-term. Radiation therapy also increases your lifelong risk of developing lymphedema. However, you can often successfully manage these long-term side effects with physical therapy.

What can you not do after radiation treatment?

There are a few things you should avoid after radiation treatment to help your body heal faster. Most importantly, don’t expose the treated area to direct sunlight because radiation makes your skin more likely to sunburn. You should also skip harsh skincare products and tight-fitting clothes that can irritate your skin. Overall, focus on protecting the skin that your radiation oncologist targeted during treatment and resting as much as you can.

What will my breast look like after radiation therapy?

Your breasts’ appearance and texture may change during radiation therapy. You might notice redness, darkening of the skin, or a sunburn-like rash in the treated area. Over time, your skin may become dry, sensitive, and prone to peeling. The breast tissue may feel firmer or denser due to fibrosis, and you might see slight changes in size or shape. Most of these changes improve gradually, so your breast should go back to normal at some point after the treatment. However, some changes can be long-term.

When do radiotherapy side effects start?

Most side effects from radiation therapy start a couple of weeks into treatment. Skin irritation and fatigue typically show up first. Side effects tend to peak toward the end of treatment or shortly after you finish. You can expect them to gradually improve over the following weeks and months.

What is the life expectancy after radiation?

Radiation therapy for breast cancer is effective at reducing recurrence and improving survival rates, so many people go on to live long lives after treatment.

But life expectancy isn’t the same as your quality of life. If you experience long-term side effects like lymphedema, limited range of motion, or chronic tightness, they can significantly impact how you feel day-to-day. Physical therapy can help with these issues so that you can not only live long, but live well.

Get More Support During and After Breast Cancer Radiotherapy

You can’t prevent all side effects from radiation therapy, but you can manage them and reduce their impact.

I created Breast Cancer Rehab to share the strategies and exercises I use with my patients at the physical therapy clinic with more people and make them more accessible.

Taking early steps can help you prevent long-term effects from developing or keep them from becoming severe. This is especially important for lymphedema after breast cancer, where early intervention makes a huge difference.

Learn more about Breast Cancer Rehab and join!