Palliative radiation therapy for gynecological cancersMedical editor Kolbein Sundfør MD
Oslo University Hospital
Symptom-directed palliative radiation therapy can be given for tumors/metastases that cause pain, bleeding, secretion, compression, bowel or airway stenosis, etc.
Radiation therapy should be offered liberally for local problems. Uncontrolled central pelvic tumors often cause bothersome side effects. To achieve local control, brachytherapy is used, also for metastatic disease.
- Symptom-causing recurrence and metastases from gynecological cancer. Both squamous epithelial carcinomas and adenocarcinomas are often radiosensitive.
|Target volume definitions from ICRU
(International Commission on Radiation Units and Measurements)
|GTV (Gross tumor volume)
||Palpable or visible/identifiable area of malignant growth.
|CTV (Clinical target volume)
||Tissue volume containing GTV and/or subclinical microscopic malignancy.
|ITV (Internal Target Volume)
||Volume containing CTV and an internal margin taking into account internal movements and revisions of CTV.
|PTV (Planning Target Volume)
||Geometric volume containing ITV and one Setup margin taking into account assumed variations for patient movements, variations in patient positioning, and field modeling.
There must be a clear connection between the tumor/metastasis and the symptom. Also, the extent of the tumor both in the treatment area and in other regions must be decided. A gynecological examination, lung X-ray, and recent CT/MR of the abdomen/pelvis are required as well as the treatment area. MRI gives the best documentation of the extent of bone metastases.
The fields are tuned directly on the simulator with the help of CT images and physical examination. If the goal of treatment is local control, CT-based dosage planning is appropriate. This also applies for certain toxicity problems. See information under treatment for recurrence.
It is very important that the patient is well medicated for pain and is able to lie still on their back while the simulation takes placed.
- Normal dosage for palliation of symptoms is 3 Gy x 10.
- Treatment with few, high fraction doses, for example 6–10 Gy x 1–3, can be considered for patients with assumed short survival time when fast symptom-relief and short treatment time is more important that the risk for late reactions to radiation.
- For painful bone metastases, 8 Gy is the standard dose in one fraction. Studies have shown an equivalent effect of pain relief to 3 Gy x 10. This treatment can be repeated with recurrence of pain. If there is a risk for fracture in the spine or long bones, a dose of 3 Gy x 10 is given, or 2 Gy x 25, for a total of 50 Gy in limited disease. The effect of treatment, however, lasts longer when lower fractions are given to higher total doses. Operative fixation before radiation therapy should be considered for patients in good general health.
- For multiple brain metastases, a dose of 3 Gy x 10 is given.
- For 1–2 brain metastases up to 2 cm, surgery should be performed if possible followed by radiation therapy 2 Gy x 23–25 to the surgical area. Stereotactic radiation should be given, if possible. This treatment should start when the surgery area is healed, preferably within two weeks. It may be appropriate to give 18–20 of the fractions to the entire brain.
Most side effects occurring during treatment are due to healthy organs included in the field of radiation. The dosage level used for pure symptom relief is, however, kept low to keep the risk for acute side effects as low as possible. At the same time, when total dose is low enough (3 Gy x 10), the risk for late reactions is low.
This applies to patients with advanced cancer. Adequate follow-up with relief of symptoms is important. Chemotherapy is used where it is still appropriate, but systemic treatment with anthracyclines is avoided in the first months. This applies also to low-dose doxorubicine and similar drugs.
Most side effects occurring during treatment are due to normal organs injured by the radiation.