Brachytherapy

Introduction

If your doctor has talked with you about brachytherapy as part of your cancer treatment, you may have many questions. Brachytherapy is a form of radiation therapy, but instead of a machine sending radiation from outside the body, the radiation source is placed inside the body, very close to the tumour. This allows a high dose of radiation to reach the cancer while sparing more of the surrounding healthy tissue.

Brachytherapy has been used to treat cancer for more than a century, and modern imaging and computer planning have made it more precise than ever. It is used for several common cancers, including those of the prostate, cervix, uterus, breast, skin, head and neck, and some others. It may be used on its own, or combined with surgery, external radiation, chemotherapy, hormonal therapy, or immunotherapy, depending on the cancer and stage.

This article explains how brachytherapy works, the main types, what to expect before, during, and after treatment, the side effects to be aware of, and how recovery typically unfolds. It is written for readers who already have a cancer diagnosis and are now planning the next phase of care.

What Is Brachytherapy?

Brachytherapy — sometimes called internal radiation therapy is a treatment in which a small radioactive source is placed temporarily or permanently inside the body, in or next to the tumour. The word “brachy” comes from the Greek for “short,” reflecting the short distance over which the radiation acts.

Radiation damages the DNA of cells, especially fast-dividing cancer cells, so that they cannot continue to grow and divide. Because the radioactive source sits very close to the tumour, the dose is highest where it is needed and falls off sharply over a short distance. This means a strong cancer-killing dose can be delivered while nearby healthy organs receive much less radiation than they would with external beam treatment alone.

Brachytherapy is delivered using small devices called applicators, catheters, needles, or seeds. These are placed by a radiation oncologist, often with the help of imaging such as ultrasound, CT, or MRI to guide them precisely. After the source is removed (or, in some cases, left permanently in place), the patient is no longer carrying an active high-dose radiation source though specific safety rules apply for permanent implants, which we describe later.

How Brachytherapy Works

To understand brachytherapy, it helps to picture what is actually happening inside the body during treatment.

First, the radiation oncology team plans the treatment using detailed imaging of the tumour and the organs around it. The plan defines exactly where the radioactive source needs to sit, for how long, and at what dose, to give the tumour enough radiation while keeping nearby tissues below safe limits. Modern planning uses three-dimensional images and computer software to calculate the dose at many points inside the body.

Next, an applicator is placed in the body. The applicator is a hollow device shaped to fit the area being treated. For example, a hollow tube may be placed inside the uterus and vagina for cervical or endometrial cancer, thin needles may be placed into the prostate, or small catheters may be placed into breast tissue around a surgical cavity. Placement is done in an operating room or procedure suite, usually under anaesthesia or sedation.

Then, the radioactive source is loaded into the applicator. With modern remote afterloading machines, a small radioactive pellet attached to a wire is driven from a shielded safe inside the machine into the applicator, held in position for a calculated time, and then withdrawn. The treatment team operates the machine from outside the treatment room. The radiation is “on” only while the source is in place. Once the source is withdrawn and the applicator is removed, the radiation stops.

In permanent seed brachytherapy, small radioactive seeds (most commonly iodine-125 or palladium-103) are placed in the tissue and left there. They give off radiation gradually over weeks to months, after which they become inactive. The seeds remain in the body but no longer pose a meaningful radiation source.

Who Receives Brachytherapy?

Brachytherapy is used for many cancers and some non-cancer conditions. Whether it is part of your treatment depends on the type of cancer, its stage and location, your overall health, and the goals of treatment.

Cervical cancer

Brachytherapy is a core part of treatment for most locally advanced cervical cancers. Major societies, including ASTRO and the American Brachytherapy Society (ABS), describe brachytherapy as an essential component of curative treatment for these cancers, typically combined with external beam radiotherapy and chemotherapy. Studies have consistently shown that adding brachytherapy improves outcomes compared with external radiation alone.

Endometrial (uterine) cancer

For some cancers of the lining of the uterus, brachytherapy is given to the upper vagina after a hysterectomy to lower the chance of the cancer coming back. This is known as vaginal cuff or vault brachytherapy. It may be used alone or with external radiation, depending on the cancer's features.

Prostate cancer

Brachytherapy is a well-established treatment for prostate cancer. Two forms are used:

• Permanent low-dose-rate (LDR) seed implantation, often offered for selected lower-risk and some intermediate-risk cancers
• Temporary high-dose-rate (HDR) brachytherapy, often combined with external beam radiotherapy and sometimes hormonal therapy for intermediate- and higher-risk cancers

Whether brachytherapy is part of treatment is decided based on the cancer's risk group, the size of the prostate, urinary symptoms, and patient preferences.

Breast cancer

After breast-conserving surgery (lumpectomy), brachytherapy may be used to deliver radiation to the part of the breast where the tumour was, rather than to the whole breast. This is called accelerated partial breast irradiation (APBI). It is offered for carefully selected early-stage cancers based on criteria from societies such as ASTRO and the ABS.

Skin cancer

Surface brachytherapy can treat some non-melanoma skin cancers, particularly when surgery would be cosmetically difficult or when a patient cannot tolerate surgery. Specialised applicators are placed against the skin and radiation is delivered over several sessions.

Head and neck cancers

Interstitial brachytherapy is used in selected cancers of the tongue, floor of mouth, lip, and other head and neck sites, often as a focused boost combined with external radiation, or for cancers that have come back after earlier treatment.

Other cancers

Brachytherapy also has a role in selected cancers of the oesophagus, lung airways (endobronchial brachytherapy), bile ducts, rectum, vagina, vulva, penis, and some soft tissue sarcomas. Eye plaque brachytherapy is used for certain eye tumours such as uveal melanoma.

Non-cancer uses

Brachytherapy is occasionally used for non-cancer conditions, such as preventing the re-narrowing of blood vessels after certain procedures, or for some benign growths. These uses are less common than its cancer applications.

Types of Brachytherapy

Brachytherapy is classified in two main ways: by the rate at which radiation is delivered, and by how and where the source is placed in the body.

By dose rate

High-dose-rate (HDR) brachytherapy delivers a strong dose of radiation over a few minutes per session. The radioactive source (usually iridium-192) is moved into the applicator by a computer-controlled machine, held in calculated positions for set times, and then withdrawn. HDR is given in one or several sessions, often over days or a few weeks. Patients are not radioactive between sessions.

Low-dose-rate (LDR) brachytherapy delivers radiation more slowly, over hours to days. In one form, the source stays in the applicator continuously during a hospital stay; in another, small radioactive seeds are permanently implanted in the tissue and release radiation gradually over weeks to months. Prostate seed brachytherapy is the most familiar permanent LDR treatment.

Pulsed-dose-rate (PDR) brachytherapy mimics the biological effect of LDR using short HDR-like pulses given every hour over a hospital stay. It is used in some specialised centres.

By placement

Intracavitary brachytherapy places the source inside a natural body cavity. For cervical and uterine cancer, applicators are placed inside the vagina and uterus.

Interstitial brachytherapy places needles or catheters directly into tissue. This is used in prostate brachytherapy, some breast brachytherapy, head and neck cancers, and certain gynaecological cancers when the tumour cannot be reached by intracavitary applicators alone.

Intraluminal brachytherapy places a catheter into a tube-like structure such as the oesophagus, bile duct, or airway, to treat a tumour that is narrowing or obstructing it.

Surface (contact) brachytherapy places the source against the skin or another surface, used most often for skin cancers and some eye tumours.

The choice of dose rate and placement is based on the cancer type and location, evidence from clinical guidelines, and the expertise available at the treating centre.

The Treatment Plan and What to Expect

Brachytherapy is usually one part of a larger cancer treatment plan. The full course may also include surgery, external beam radiation, chemotherapy, hormonal therapy, immunotherapy, or other treatments. Your radiation oncologist and the wider multidisciplinary team decide on the sequence and combination.

Before treatment

Before brachytherapy, you will have appointments to plan the treatment. These typically include:

• A detailed discussion of your diagnosis, the role of brachytherapy in your treatment, the expected benefits, and the risks
• A physical examination focused on the area being treated
• Imaging such as CT, MRI, or ultrasound, used both to plan the placement of applicators and to design the radiation dose
• Blood tests and other pre-anaesthesia checks if anaesthesia or sedation will be used
• For gynaecological cancers, an examination under anaesthesia may be done at the start to confirm tumour size and shape

You will be told which medicines to continue or pause, what to eat or drink before the procedure, whether you need someone to accompany you home, and how to prepare practically (for example, arrangements for the bladder and bowel for pelvic brachytherapy).

The procedure itself

What happens on the day depends on the type of brachytherapy.

For cervical or uterine brachytherapy, applicators are placed in the operating room under anaesthesia or sedation. Imaging is then done to plan the dose precisely. The applicator is connected to the afterloading machine, the radioactive source is driven into position and held for several minutes, and then withdrawn. Some patients have the applicator removed after each session; others have it kept in place for a short hospital stay covering several treatments.

For prostate brachytherapy, thin needles are placed into the prostate through the perineum (the skin between the scrotum and anus), under spinal or general anaesthesia and ultrasound guidance. In LDR treatment, small radioactive seeds are deposited along the needles and left permanently in place. In HDR treatment, the needles are connected to the afterloader for the treatment dose, then removed.

For breast brachytherapy, small catheters or a single multi-channel applicator are placed in the breast around the lumpectomy cavity. Treatment is given in multiple sessions over about a week, after which the catheters are removed.

For skin brachytherapy, custom moulds or surface applicators are positioned against the skin and treatment is delivered over several short sessions.

Treatments themselves are not painful, because the radiation cannot be felt. Discomfort, when it occurs, is usually from the applicators or from staying in one position. Pain relief is given as needed.

Hospital stay or outpatient

Some forms of brachytherapy are outpatient procedures, allowing you to go home the same day. Others require an overnight or short hospital stay, especially when applicators must remain in place between fractions. The team will explain your specific schedule in advance.

Radiation safety

While the radioactive source is in the body, certain safety rules apply for staff and visitors. For HDR treatment, you are only radioactive while the source is in position — outside those few minutes, no precautions are needed. For temporary LDR or PDR treatments with the source in place over hours or days, hospital staff limit close contact, and visitors may be restricted, especially pregnant women and young children.

For permanent seed implants, such as prostate seed brachytherapy, most of the radiation stays within a few millimetres of the seeds. Your team will give clear written advice on safety, usually involving simple measures for the first weeks or months — for example, limiting prolonged close contact with pregnant women and young children, and following specific instructions if you travel. The seeds eventually become inactive.

Side Effects and How They Are Managed

Side effects depend strongly on the area being treated. Brachytherapy spares more healthy tissue than external radiation alone, but some side effects are still expected. They are grouped into early effects (during and shortly after treatment) and late effects (months to years later).

Pelvic brachytherapy (cervical, uterine, prostate, vaginal)

Early effects may include:

• Fatigue, especially during a course combined with external radiation and chemotherapy
• Bladder irritation: needing to pass urine more often, burning, urgency
• Bowel changes: loose stools, urgency, irritation of the rectum
• Vaginal discharge, soreness, or light bleeding (for gynaecological treatments)
• Perineal soreness, bruising, or temporary urinary symptoms after prostate brachytherapy

Late effects may include narrowing or dryness of the vagina, persistent bowel or bladder sensitivity, urinary symptoms (in men, including weak stream or urgency), erectile difficulties after prostate brachytherapy, and rare effects on nearby organs. Vaginal dilator use and pelvic floor advice may be part of recovery after gynaecological brachytherapy; doctors and specialised nurses or physiotherapists guide this.

Breast brachytherapy

Common early effects include skin redness, soreness around catheter sites, bruising, and short-term breast swelling. Late effects can include changes in breast shape or texture, small areas of firmness (fibrosis), and small visible blood vessels in the skin. Most women have a good cosmetic outcome, although results vary.

Skin brachytherapy

Skin reactions in the treated area — redness, peeling, soreness — are common during and after treatment. The skin usually heals over weeks. Long-term changes may include altered pigmentation, thinning, or small blood vessels in the treated area.

Head and neck brachytherapy

Side effects may include mouth soreness, taste changes, dry mouth, and difficulty swallowing during and shortly after treatment. Late effects depend on the area and may include dryness, tissue stiffness, or, rarely, jawbone problems.

General supportive care

Your treatment team will discuss what to watch for, when to call, and how to manage common effects with medications, skin care, pelvic care, hydration, and other measures. Some side effects are noticeable only after treatment ends, so follow-up appointments are an important part of care.

Response and Monitoring

Brachytherapy's effects unfold over weeks to months. Cancer cells damaged by radiation continue to die off for some time after the radioactive source has been removed or has decayed.

Follow-up after brachytherapy varies by cancer type, but generally includes:

• Physical examinations at regular intervals
• Imaging such as MRI, CT, or ultrasound to assess the treated area and check for any sign of cancer return
• Blood tests where relevant — for example, prostate-specific antigen (PSA) for prostate cancer
• Symptom review to detect and manage any late side effects

Response can be slower to interpret than after surgery, because the treated tissue takes time to settle. For prostate cancer, for example, PSA values may rise briefly before falling. Your radiation oncologist will explain the pattern that is expected for your cancer and what would be considered a concern.

Combining with Other Treatments

Brachytherapy rarely stands alone in modern cancer care. It is most often combined with other modalities according to evidence-based protocols.

With external beam radiotherapy: Many cancers are treated with a course of external radiation followed by a brachytherapy boost. This combination delivers a high total dose to the tumour while sparing nearby healthy tissue. Cervical cancer treatment is a key example, where major societies describe combined external radiation and brachytherapy with chemotherapy as the standard curative approach for locally advanced disease.

With surgery: Brachytherapy may be given after surgery (for example, vaginal vault brachytherapy after hysterectomy for endometrial cancer), or before surgery in some sarcomas. In selected breast cancers, brachytherapy after lumpectomy replaces whole-breast external radiation as accelerated partial breast irradiation.

With chemotherapy: Chemotherapy given alongside radiation (chemoradiation) is used for several cancers, including cervical cancer. Brachytherapy is then included as part of the radiation component.

With hormonal therapy: For higher-risk prostate cancer, hormonal therapy may be combined with brachytherapy and external radiation.

The specific combination, sequence, and timing are decided by the multidisciplinary team based on the cancer type, stage, and individual factors.

Recovery and Living During and After Treatment

Recovery from brachytherapy depends on the type and site of treatment, what other treatments are being given, and your overall health.

The first days after a procedure

After applicator placement and the radiation session, you may feel sore, tired, or crampy. Pain control is offered as needed. For prostate brachytherapy, swelling can cause temporary urinary symptoms; a urinary catheter is sometimes used briefly. For gynaecological brachytherapy, some vaginal discharge or light bleeding may occur. The team will give clear instructions about activity, hygiene, sexual activity, and when to seek help.

The weeks that follow

For permanent seed implants, you may be asked to follow simple safety advice for a defined period — for example, limiting close contact with pregnant women or young children for a set number of weeks, sleeping arrangements, condom use during the first ejaculations, and what to do if a seed is ever passed (rare). Written instructions are provided.

Sexual health and intimate life

Many people understandably have questions about sex and intimacy after brachytherapy. For pelvic brachytherapy in women, vaginal dryness, soreness, or narrowing can occur; vaginal dilator use, lubricants, and time often help. After prostate brachytherapy, erectile function may decline gradually; medication and other treatments can help in many cases. Discussing concerns openly with your radiation oncologist or specialist nurse leads to better support.

Fertility and contraception

Radiation to the pelvis can affect fertility in both women and men. If having children in the future is important to you, this should be discussed before treatment starts, so options such as fertility preservation can be considered. Contraception advice is given where relevant during and after treatment.

Returning to work and daily life

When you can return to work, exercise, driving, and social activities depends on the type of brachytherapy and your overall recovery. Many people resume light activities within days, with a gradual return to fuller activity over weeks. Your team will give you specific guidance.

Emotional well-being

Going through cancer treatment is emotionally demanding. Anxiety about results, fatigue, body image changes, and changes in intimate life all matter. Talking to family, friends, peer-support groups, or a mental health professional with experience in cancer care can help. Many treating centres have a clinical psychologist or counsellor available.

Brachytherapy in Children

Brachytherapy is used much less often in children than in adults, but it has a role in selected paediatric cancers such as some soft tissue sarcomas (including rhabdomyosarcoma of the bladder, prostate, vagina, or head and neck region) and certain retinoblastoma cases (using eye plaque brachytherapy). Because children's tissues are still developing, the balance of benefits and long-term risks is considered very carefully.

Where brachytherapy is used in children, it is typically delivered in specialised paediatric oncology centres by teams experienced in the technique and in supporting the child and family through treatment. Anaesthesia or sedation is almost always used during applicator placement, and play specialists or child-life support are often involved to help children cope. Long-term follow-up focuses on cancer outcomes and on monitoring for late effects on growth, fertility, organ function, and second cancers, which are particular concerns in younger patients.

If brachytherapy is being considered for a child, the paediatric oncology team will explain how the technique is being adapted, why it is preferred over (or combined with) other treatments, and what the follow-up plan will look like over the long term.

Choosing a Brachytherapy Centre

Brachytherapy is a highly technical treatment. Outcomes depend not just on the equipment but on the experience of the radiation oncologist, medical physicist, radiation therapists, and nursing team, as well as on the availability of appropriate imaging for planning.

In general, factors that matter when treatment is being planned at a particular centre include:

• Experience of the team with your specific cancer type and the brachytherapy technique being proposed
• Availability of image-guided planning (CT, MRI, ultrasound) appropriate for your cancer
• Multidisciplinary working with surgeons, medical oncologists, gynaecological oncologists, urologists, and other specialists as relevant
• Support services such as specialist nursing, psychological support, physiotherapy, and rehabilitation
• A clear plan for follow-up and long-term care

These are conversations to have with your treating team, often supported by your wider family. Meeting more than one specialist before deciding is reasonable when time allows.

Frequently Asked Questions

Will I be radioactive after brachytherapy?

For HDR brachytherapy, no. The radiation is “on” only while the source is in the applicator, and the source is removed at the end of each session. You can be around family, including children and pregnant women, immediately afterwards.

For temporary LDR or PDR brachytherapy with the source in place during a hospital stay, you carry the source until it is removed. Visitor restrictions apply during that time. After removal, you are not radioactive.

For permanent seed brachytherapy (such as prostate seed implants), the seeds give off radiation gradually for weeks to months. The radiation does not travel far, but simple precautions are advised for a defined period, as set out in your written instructions.

Does the procedure hurt?

The radiation itself cannot be felt. Discomfort, when it occurs, comes from applicator placement, staying still during treatment, or local soreness afterwards. Anaesthesia or sedation is used when applicators are placed, and pain relief is given as needed.

How many sessions will I need?

The number of sessions depends on the cancer type, the brachytherapy approach, and whether it is combined with other treatments. Some treatments are completed in a single permanent implant (such as prostate seed brachytherapy), some involve a few HDR sessions over one to two weeks, and others involve a short course over a few days. Your radiation oncologist will give you a specific schedule.

Is brachytherapy better than external beam radiation?

The two approaches are not interchangeable, and one is not universally “better.” They have different strengths. Brachytherapy delivers a very high dose to a small area, while external beam radiation can treat larger areas and lymph nodes. For many cancers, the best results come from combining the two. Major societies have specific guidelines about when each approach, or the combination, is preferred for particular cancers and stages.

What is the difference between HDR and LDR brachytherapy?

HDR (high-dose-rate) brachytherapy delivers a strong dose over minutes per session, with the source removed after each treatment. LDR (low-dose-rate) brachytherapy delivers radiation more slowly, either with a source in place over hours to days, or as permanent seeds that release radiation gradually. Both approaches are well-established. Which is used depends on the cancer, the treating centre's expertise, and patient factors.

Will brachytherapy affect my ability to have children?

Radiation to the pelvis can affect fertility in both women and men. If preserving fertility is important to you, discuss this with your team before treatment starts, so options for fertility preservation can be considered. Contraception advice is also discussed as relevant.

Can brachytherapy be repeated if the cancer comes back?

In some situations, re-treatment with brachytherapy is possible, particularly when the tumour is small and located where additional radiation can be delivered safely. Re-treatment is decided case by case based on the original treatment, the recurrence, and the surrounding tissues.

How soon will I know if treatment has worked?

Brachytherapy's effects unfold over weeks to months. Imaging and blood tests at follow-up appointments help judge the response. For some cancers, tumour shrinkage and falling tumour markers are seen gradually. Your radiation oncologist will explain the expected pattern for your cancer and what they will be looking for at each follow-up.

What should I do if I notice new symptoms after treatment ends?

Some side effects appear or persist after treatment ends. Mild and expected effects are managed with the supportive measures your team has described. New, severe, or worsening symptoms — such as heavy bleeding, fever, difficulty passing urine, severe pain, or any symptom you are unsure about — should be reported to your team promptly so they can be assessed.

Conclusion

Brachytherapy is a precise form of internal radiation therapy that has been part of cancer care for more than a hundred years and continues to evolve with modern imaging and planning. It is used for cancers of the cervix, uterus, prostate, breast, skin, and many other sites, either alone or alongside surgery, external radiation, chemotherapy, and other treatments. By placing the radioactive source very close to the tumour, brachytherapy delivers a high dose where it is needed while sparing more of the surrounding healthy tissue.

What brachytherapy looks like in practice — the type, the number of sessions, the side effects, and the recovery — varies from one cancer and one person to another. The most useful next step is a detailed conversation with your radiation oncologist and wider treatment team, in which the role of brachytherapy in your specific plan is explained, your questions are answered, and a clear plan for treatment, supportive care, and follow-up is agreed.