Radiotherapy for Cervical Cancer

Cervical cancer affects the cervix, which is a flexible passage between the vagina and the uterus. The World Health Organization is known to have reported that cervical cancer is the second most common cancer in women worldwide, with around 500,000 new cases and 250,000 deaths each.  With the advent of screening programs and better methods to treat cervical cancer, the incidence of cervical cancer has been reduced. The Pap smear test is helping a lot in this regard by identifying precancerous and early invasive stages of cervical cancer.

Radiation Therapy:

The role of cervical cancer radiotherapy  is used to kill cancerous cells using radiation. For cervical cancer treatment, usually external radiation is given. X-rays are introduced externally, at least for a period of 6 – 7 weeks. Radiotherapy is a painless as well as a non-invasive method. This technique is called as external beam radiation therapy. It may be complemented by a low dose of chemotherapy with the drug Cisplatin for better results.

However some patients might need internal radiation therapy, also called as brachytherapy.

When is Radiotherapy Given?

Cervical cancer Radiotherapy becomes the treatment of choice when the tumor is large and not curable with surgery alone. It may be used alone or in combination with chemotherapy which is then referred to as chemoradiation. Radiation is also advised by oncologists when the chances of recurrence of cervical cancer are high.

Your radiation oncologist will discuss the possible side effects of your treatment with you, They shall also add certain medications to your treatment regime that may help decrease these side effects.

External Radiotherapy:

  • Cervical cancer Radiotherapy is given on an outpatient basis with the patient coming to the doctor’s clinic every day and receiving the prescribed dose of radiation.
  • The patient is seated comfortably on a couch, and an external source is placed near the affected area (cancer) and after a few days of radiation, doctors may advise the patient a rest of 1-2 days. The procedure often lasts for a few weeks; however this depends on the type and stage of cancer.  

Radiation therapy is not a painful procedure, and the patient is not radioactive afterward; it is completely safe to interact with children or any other persons without any associated risk.

Internal Radiotherapy:

  • Internal radiotherapy is also referred to as Brachytherapy; this involves placing specially designed tubes (applicators) that emit radiation inside vagina and direct radiation is hence given to the cervix (cancerous area) and the area close by. Brachytherapy is often given as an adjunct to external radiation.
  • Internal radiation may be given as a high dose or low dose treatment.
  • The amount of radiation given in either remains the same. However, the period over which it is given varies.

Treatment as an Inpatient:

  • Patients may be admitted to the hospital for the amount of time they have to receive the radiation. Various techniques have been adopted by different hospitals to give internal radiation.
  • Continuous radiation is available in some hospitals that allow a low dose to be emitted continuously.
  • Often the applicators emitting the dose have the ability to be switched off temporarily in case someone enters your room to protect the other person from unnecessary exposure to radiation.
  • In other places, a PDR (pulsed dose rate system) may be used. It uses Iridium 192 as its source of radiation. The difference in PDR versus continuous radiation therapy is that PDR emits a higher dose of radiation for ten minutes each hour. It is safer than continuous radiation and is more easily interrupted ensuring more visitors’ safety.
  • The applicators are held in place using a gauze piece. It is not painful; however, it may be a little discomforting. Patients may still be prescribed painkillers that are adjusted according to the patient’s needs.
  • In case the applicators are dislodged, you should immediately inform your doctor. Since it will be hard for the patients to get out of bed if the applicators get dislodged, a bell will be placed beside your bed that will allow you to call a nurse for assistance at all times.

For any side effects that one may encounter during the treatment, the doctor will prescribe medications so as to ease the unwanted symptoms. Depending upon how one feels after the recommended dose of radiation has been administered, patient discharge will be planned soon after the applicators are removed.

Treatment as an Outpatient:

  • The role of cervical cancer radiotherapy in treatment as an outpatient is administered as a high dose rate treatment. A source is placed that delivers radiation to the right place and is removed after that. The machine emits the required dose of radiation quickly resulting in a shorter period of treatment, however, since a quick, higher dose of radiation may produce many side effects, patients are given a fraction of radiation once every week.
  • High Dose Rate treatment was approved by the NICE as a safe alternative to being used for giving radiotherapy in 2006. It is rendered safe as a low dose treatment and is effective. However, it is recommended that the doctors explain the possible side effects to the patients. It was also advised that adequate pain relief is given with the treatment as this procedure may be painful.
  • To avoid an anesthetic to be given every time, a small cuff may be placed for the complete course of the treatment to guide the placing of the applicators.
  • Patients are often allowed to go home once the effect of anesthetic has worn off. However, vaginal bleeding may follow, and other side effects like diarrhea may also occur. Sometimes, if the doctor feels it necessary, he may ask you to stay in the hospital overnight especially if adequate help at home is not available.

Low Dose Rate Treatment:

  • Selectron is a device that can be placed inside the patient’s vagina to administer low dose rate treatment on an inpatient basis. The applicators are placed using a local anesthetic and painkillers are administered as this may be discomforting to the patient. The radioactive balls are automatically retreated into the machine when someone enters the room to avoid unnecessary exposure.
  • During treatment, it is best to limit the number of people visiting you, especially children. Since you will be confined to bed to avoid displacing the applicators, a urinary catheter may be placed so that you need not get out of bed too frequently and risk displacing the applicators.
  • If you feel that limiting visitors may make you feel lonely or depressed, it is best to talk to your doctor or nurse so that support may be provided to you. The isolation period lasts only till the radiation is actively being received and during this time patients are advised to keep themselves occupied by reading a book or taking along their mp3 players, etc.
  • After the treatment dose has been given, the applicators may be removed using anesthesia. Since this is a painful process air or gas may help to ease the pain at the time of removal of applicators.

High Dose Rate Treatment

  • A machine (micros electron) containing iridium or cobalt as its radiation source is used to give high dose rate treatment to patients. It gives a considerably higher dose over a much shorter period.
  • As with the other sources, to avoid the pain, pain relief medicines will be administered before inserting the applicators. These applicators are connected to a machine that provides the radiation. Patients may receive this kind of treatment on an outpatient or inpatient basis, and may be given over a period of days repeatedly for some time.

Side effects of low and high dose therapy:

The therapy has several undesirable effects too. The most common side effects associated with radiotherapy are:

  • Nausea, vomiting, tiredness and diarrhea. These side effects are more pronounced when chemotherapy is given along with radiation. Internal radiation therapy has more side effects than the external radiation therapy.
  • The therapy can cause decreased red blood cell count (anemia) and the decrease in white blood cells (leucopenia). However, the red blood and white blood cell counts return to normal once the radiation is stopped.
  • Prolong radiation (2-4 years) can lead to the weakening of the bones, and hip fractures are very common.
  • Pelvic radiation can also lead to shortening of the vagina, destroying ovaries leading to early menopause, cause vaginal stenosis and make vaginal intercourse painful. However these effects as a result of prolonged radiations and can be prevented. Use of vaginal estrogens, vaginal dilators and stretching vaginal walls can help prevent these side effects.

Pulsed Dose Rate Brachytherapy (PDR):

Only a few specialist hospitals offer this treatment modality. Like low dose treatment, PDR applicators are placed for the same amount of time. However, over a shorter duration, higher doses are administered.

Conclusion:

Cervical cancer is the second most common type of tumor among women worldwide. The role of radiation therapy in the treatment of cervical cancer is due to its ability to kill cancer cells by using radiation. External radiation is more commonly used for this purpose. Radiotherapy is used in those cases where cancer is too large and is not curable by surgery. Various kinds of radiation therapy are available, which are used depending upon the location and type of cancer.

 

References:

Cervical cancer radiotherapy

Cervical cancer and types of radiotherapy