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There may be some side effects from radiation therapy for certain types of treatments. Your doctor can explain the potential risks in detail – and, if necessary, give you some medications to help.

Is radiation therapy radioactive?

Radiation therapy doesn’t make you radioactive. When your treatment is finished, you can go home, play with your children or grandchildren, carry on working, and resume your normal routine. You don’t need to worry about putting anyone around you at risk.

Will I feel tired?

Feeling tired is the most common side effect of radiation therapy.

You feel tired because your body has to use more energy to heal itself after each treatment.

People have described this feeling as the entire body feeling too heavy to move.

Stress, medications and the time spend travelling to medical appointments can also make you feel more tired than usual.

How can I manage the tiredness?

During your treatment program, it’s important to rest a lot – and nap during the day if you can.

Managing your time, prioritising your essential tasks, and asking – and accepting – help from others will also help you manage your tiredness.

While we want you to get enough rest, we don’t recommend complete bed rest or being too still all the time. Light exercise – even a 20-minute walk – can also help to make you feel less tired.

Establish a good sleep routine, and practice relaxation techniques if you’re feeling anxious about your treatments.

If you’re finding it hard to sleep, please talk to your doctor.

Will my skin change?

Because your skin constantly regenerates, it often reacts to radiation.

The most common reaction is erythema—a drying and reddening of the skin that can appear on or within the treated area.

Other reactions can be skin inflammation, dry skin, moist skin, and skin peeling.

In the pelvis, skin reactions with modern radiation therapy aren’t common until later on in your treatment course – and you might not need to use moisturiser at first.

In more sensitive areas, like the pubic area, groin, perineum and between the buttocks, you may notice reactions such as:

  • Skin becoming pinker than normal
  • Skin becoming irritated dry or flaky
  • Skin becoming red, sore or sensitive toward the end of treatment
  • Temporary hair loss in the pubic area

Before your treatment begins, our nursing staff will give you advice and resources to help you care for your skin.

burn side effect cancer genesis cancer care

Some general tips to help you look after your skin during treatment include:

  • Use moisturiser or vitamin E cream – apply cream to the treated area to help keep your skin nourished. This also maintains skin integrity and reduces the chance of reddening. Choose moisturisers that don’t contain alcohol or fragrances, so they don’t irritate your skin.
  • Take care of the treatment area – don’t rub it or scratch it, and try to keep it cool and away from extreme heat.
  • Avoid deodorants in the treated area – underarm deodorants are fine, but avoid using them in the treated area if it starts to become sensitive. You will be given advice from your local nursing team about how best to use deodorants.

Will I lose any hair?

Hair loss is an unfortunate side effect of radiation therapy, and you may find you lose some underarm hair – either temporarily or permanently – in the area that’s being treated.

When you have radiation therapy, you will only experience hair loss in the area that’s being treated – so you won’t lose any hair on your head or legs, for example.

In many cases, your hair will grow back when your treatment has finished – though it may not be as thick as it was before your treatment.

How long will my hair take to grow back?

This depends on the dose of radiation therapy you have received – as well as how long you were receiving treatment for. For most people, hair grows back within 6-12 months of finishing their treatment.

Sometimes, after a large dose, your hair may not recover completely and may appear patchy.

What changes will I notice in my bladder?

During your treatment course, you may develop an uncomfortable feeling – or a burning sensation – when urinating.

You might notice that you need to urinate more often – especially at night, and often with a slower stream.

If you’re experiencing these types of symptoms, the following tips can help:

  • Avoid eating acidic foods, such as orange, tomatoes and fruit juices
  • Avoid alcohol and caffeine containing drinks including coffee
  • Drink plenty of water, and stay well hydrated at all times

Your radiation oncologist can prescribe medication to reduce bladder irritability and improve urine flow. Your symptoms will usually subside in the weeks after radiation therapy has finished.

What bowel changes will I notice?

You may notice you have more frequent bowel movements and are passing more gas than usual.

Stool softeners can help to keep bowel motions soft and void the need to strain.

Diarrhoea is less common, but you may experience it later on in your treatment course.

This can be minimised by eating a diet with a high amount of fibre. Cutting out foods that irritate the bowel can also help.

If none of those changes work, over-the-counter medication can help (but should be used sparingly).

Irritation or soreness of the rectum might last for a few weeks after your treatment. Medicated ointment and suppositories can help with this symptom, so speak to your radiation oncologist for a treatment recommendation.

Do I need to change my diet whilst having radiation treatment?

It is important to keep your bowel motions soft and regular during treatment.

Eating a well-balanced diet with sufficient fibre will help to keep the bowels soft.

If you become constipated, fibre supplements or stool softeners can help.

Later in your treatment course, you may need to reduce the amount of fibre you eat if your bowel motions become very soft or loose.

Dietary fibre also causes gas. Cutting back on very high fibre foods, such as broccoli, cabbage and other leafy greens, can help to manage this symptom.

Other foods to avoid which may cause bowel irritability include:

  • Nuts and seeds, multigrain bread with lots of seeds
  • Vitamin capsules with oily contents and fish oil capsules
  • Foods which are deep fried or cooked in oil
  • Spicy foods or foods that contain chili, cayenne or black pepper
  • Acidic foods and drinks – orange, pineapple and tomato juices
  • Alcoholic Beverages and drinks high in caffeine

It’s not necessary to completely eliminate these foods and drinks from your diet. But if you do experience these symptoms, consuming less of these foods can be helpful

Also, remember to drink plenty of water throughout the day to stay well hydrated.

Cigarette smoking significantly increases both short term and long term bowel and bladder side effects. We strongly recommend you quit smoking before your radiation therapy commences. Speak to your radiation oncologist if you need help or support quitting.

When can I resume sexual intercourse?

You don’t need to stop sexual activity during or after your treatment. A burning sensation on ejaculation is not unusual.

We recommend you use contraception during and for a minimum of 6 months after your radiation treatment.

What are the long term side effects of radiation therapy?

Long term effects on the prostate can occur between 3 and 24 months after treatment has finished.

Bowel changes

It’s not uncommon for the bowels to work twice a day, or occasionally more often, when before treatment they only opened once a day

Over time, this does improve. Other changes, such as passage of rectal mucus - a clear discharge - commonly settle and resolve in the first 6-12 months.

If you notice rectal bleeding later on, there could be a degree of chronic radiation proctitis. This would be coming from the front wall of the rectum, next to the treated area of the prostate or prostate bed.

This symptom should be reported to your radiation oncologist or your doctor – they will arrange testing and help you with next steps.


Tiredness, a common side effect of your therapy, can make you lose interest in sexual intercourse.

Radiation therapy treatments can also lead to longer term changes in blood flow into and out of the penis, as well as the delicate nerves supplying the penis. As a result, erections may not work as well or be as well maintained as they were previously.

These conditions often respond well to medication, either in tablet or injection form, and you can discuss these with your treating doctors.

Urethral stricture

After radiation therapy to the prostate, there is a small risk that the urethra (the tube that flows out of the bladder) will narrow. This can result in a reduced urine flow, and there may be dribbling or spraying as a result.

If you notice these symptoms, report them to your doctor. You may be able to have a treatment that can gently stretch the narrowed tube and improve the flow.

Urinary symptoms

Because the pelvic floor muscles lie below the prostate and are in the path of the treatment beams, they can be impacted by the treatment.

Pelvic floor exercises are recommended before, during and after radiation treatment. These exercises will improve pelvic floor muscle strength and minimise leakage or incontinence.

Bladder over-activity or irritability can be helped by specific bladder training exercises – as well as maintaining a weight loss and fitness program. Your doctor might also recommend medication to help.

Haematuria, which is blood in the urine, is sometimes seen in the first two years after radiation therapy.

Any instance of blood in the urine should always be reported to your doctor and investigated with follow-up testing.

The presence of blood in the urine could mean there is some form of chronic radiation cystitis, which is inflammation of the wall of the bladder in the treatment area.

Or, it may be unrelated to the radiation and due to another treatable condition.

There’s a lot of information to take in when it comes to side effects, but remember that your medical team are here to help answer any of your questions and provide the best possible care for you.

Your radiation oncologist will discuss these possible longer term side effects in detail before you start your treatment.

What if I’m not coping?

It’s very common to feel anxious, stressed or like you’re unable to cope during this challenging time.

We understand this is an incredibly emotional experience, and there will be many ups and downs along the way. Remember, you don’t have to go through this alone – we’re here to support you at every stage of your cancer experience.

Please talk to your radiation oncologist or radiation oncology nurse if you’re feeling like you’re unable to cope. Our team can find you services and resources to help with your specific concerns – and, we can help you fast track an appointment if necessary.

Also, the Cancer Council is a wonderful resource, and has information about a wide range of options.

How can I best look after my health?

Making your health a priority can help you to feel better before, during and after your treatments. If you have specific questions about your diet, ask to speak with an oncology dietitian.

It’s also vital you keep your gums and teeth healthy before and during treatment. Doing this helps to reduce the severity of side effects – and it can prevent longer-term problems with your mouth and teeth.

Remember, taking care of yourself is essential. Aim to:

  • Exercise regularly – light walking in the fresh air, for example
  • Eat a healthy diet, full of fresh wholesome food – remembering to avoid foods listed above if necessary
  • Get enough sleep every night – aim for 8 hours
  • Relax, and reduce stress – meditation can help
  • Laugh – and spend time with your loved ones
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