Skip to content

External Radiotherapy

  1. Introduction

    Radiotherapy involves the use of high energy X-rays or electron beam to destroy the tumour while trying to preserve normal tissues as far as possible. Although X-rays also affect normal cells in the treated area, their ability to recover is usually better than tumour cells.

    Radiotherapy can be categorised into internal and external radiation therapy. While generic information about external radiation therapy is included in this page, details about different internal radiation therapies are covered under pages for respective cancer types.

    Radiotherapy can be used for:

    • Curative therapy: offering the best chance of cure for patients who have early-stage lung cancer, early-stage prostate cancer, etc.
    • Neoadjuvant treatment that also comprises chemotherapy: some patients require such treatment before surgery to facilitate surgical resection. This applies to patients with colorectal cancer, etc.
    • Adjuvant treatment after surgery: using high energy X-ray beams to destroy potential residual tumour cells around the surgical wound to reduce the risk of recurrence. It can be used for treating breast cancer, stomach cancer, etc.
    • Palliative treatment: using radiotherapy to relieve the discomfort caused by the cancer such as pain and bleeding. It is usually applied in the advanced stage of cancer.
  2. Preparation

    • The treatment plan and radiotherapy schedule depend on the type and location of the tumour and patients’ health condition. Doctors will discuss the details with patients and explain how to cope with the treatment side effects.
    • Sometimes, skin tattooing or a special mould will be made to improve treatment accuracy.
    • Staff will take written, photographic and radiographic records of treatment details for planning of radiotherapy and future reference. These records may be used for research or scientific publication provided that strict confidentiality is maintained at all times.
    • Avoid applying ointments or creams on the area treated before the radiotherapy session. No other preparation is required unless specific instructions given by the staff.
    • Radiotherapy can cause teratogenicity. During radiotherapy, both male and female patients should take contraceptive measures.
    • Radiotherapy may affect the function of a pacemaker. Patients having a cardiac pacemaker should inform doctors.
  3. Procedure

    • Before each session, the staff will make sure that patients are in the correct position for treatment, who will then stay in the treatment room alone for minutes for the radiotherapy.
    • Patients will be closely monitored through a closed circuit television system. If necessary, the patients can also communicate with the staff by using the intercom.
    • No pain will be experienced during the treatment procedure.
    • The courses of curative and adjuvant radiotherapy usually take several weeks while that of palliative radiotherapy generally takes less than 2 weeks. Patients should inform the staff when they are feeling unwell anytime during the treatment period.
  4. After the treatment

    • Patients may feel tired or experience other side effects with radiotherapy. Patients can consider inviting a friend or relative to accompany them to the hospital if possible.
    • Doctors will assess the patients on a regular basis and take appropriate measures to minimize treatment reactions.
  5. Risk and complications

    • Although radiotherapy is an effective treatment for cancer, it can cause short-term and long-term side effects. Medical and nursing staff will offer appropriate treatments to help patients complete the course of radiotherapy and recover.
    • Each patient reacts differently and may experience none, some, or all of the complications to a varying degree of intensity. If other types of treatment such as chemotherapy are given in conjunction with radiotherapy, some of the side effects may be exacerbated. Complications are also more common in patients who had previous surgery or radiotherapy to the area treated.
    • Early- or short-term side effects may occur during or immediately after radiotherapy, but usually disappear several weeks after completing the treatment. These include:
      • Tiredness, nausea and decreased appetite.
      • Skin dryness, reddening, irritation or darkening in the area treated.
      • Skin blistering or peeling.
      • Swelling of subcutaneous tissue.
      • Temporary hair loss in the area treated.
      • Inflammation of nasal or oral mucosa, causing pain and swallowing difficulty (if close to the nose or mouth).
      • Inflammation of conjunctiva (if close to the eyes).
      • Inflammation of the conjunctiva and / or lacrimal gland, leading to red, watery and irritable eyes.
      • Peeling or skin loss is uncommon or rare.
    • Late- or long-term side effects may occur months or years after radiotherapy and may persist. These include:
      • Skin dryness, thickening and colour change.
      • Hardening and wasting of subcutaneous tissues due to fibrosis.
      • Non-healing skin ulcer.
      • Nosebleeds due to thinning of nasal mucosa (if close to the nose).
      • Permanent hair loss.
      • Reduced tear secretion (if close to the eyes).
      • Ectropion (i.e. folding outwards of eyelid) or entropion (i.e. folding inwards of eyelid) if close to the eyes.
      • Cataract (if close to the eyes).
      • Uncommon or rare side effects include:
        • Necrosis of skin, soft tissue or bone, which may require surgical treatment in severe cases.
        • Stiffening and wasting of muscles.
        • Joint stiffness with reduced range of movement if the joint receives high radiation dose.
    • Radiation-induced tumours, severe life threatening complications due to radiotherapy and death may occur but are rare.
    • Growth of irradiated area may be affected in children.
    • It is possible that the intended treatment outcome cannot be achieved, the disease may not be alleviated and it may recur or progress in the future.
    • Despite all precautions, unpredictable and unpreventable adverse outcomes may occur after treatment. Patients should consult the medical team and fully understand the details before deciding on undergoing the treatment.
  6. Follow up

    • Recovery varies individually, some people can go back to work shortly after completion of the treatment.
    • After completing the whole course of the radiotherapy, a follow-up appointment will be arranged to assess patients’ response to the treatment and look out for complications. Patients should attend the appointment as scheduled.
    • Patients must follow instructions strictly on taking medication as directed.
  7. Remarks

    Should you have any queries, please consult doctor-in-charge.