Brachytherapy refers to radiation therapy for treating many types of cancers such as skin, brain, breast, cervical, lung, prostate, eye, etc. The technique involves placing radioactive seeds (Iodine 125) or materials inside or close to the tumor. Ocular brachytherapy consists of placing a gold plaque (radiation implant or radioactive source) containing radioactive seeds on the eye's surface in a surgical procedure. The gold material is used to protect the body from the radiation contained in the seeds. Cancer treatment takes place the entire time the plaque is in the eye (usually five to seven days) before the gold plaque is removed in a subsequent surgery.
Patients with intraocular cancer are treated with brachytherapy as a vision-sparing alternative. Plaque radiotherapy is the most popular method for treating choroidal melanoma. This form of radiotherapy is designed to deliver highly concentrated radiation levels to the tumor and avoid delivering radiation to the surrounding healthy tissues. How much radiation to give to the tumor depends on the number, strength, and type of seeds used, and how long the implant will last in the body. Radiation doses also depend on the size and location of the tumor.
Also Known As
- Internal radiation
Before the Procedure
A week before the procedure, the patient meets with the radiation oncology team. During this time, a patient’s medical and surgical history is reviewed. The patient should disclose all medications including over-the-counter drugs, any patches or creams being used. The patient is advised to stop taking certain medications like nonsteroidal anti-inflammatory drugs, blood thinners like aspirin, medicines that cause bleeding, and herbal supplements, at least seven days before the procedure.
The physician will conduct electrocardiogram tests to check the patient's heart rhythm, along with blood tests, imaging scans, and other necessary tests. If need be, the physician can have the patient checked by a specialist like a cardiologist. The radiation oncologist determines the size of the plaque and how long the patient will wear it.
The patient is advised to take certain medications on the morning of the surgery. Eating anything after midnight on the eve of the procedure is prohibited. From midnight until two hours before arriving at the clinic, the patient should drink 12 ounces of water. All metal objects including jewelry and body piercings, should be removed. No makeup and other such things are allowed.
- The patient is put under anesthesia
- The specialist places a breathing tube through the mouth and into the windpipe to assist the patient to breathe
- The ophthalmologist, working together with the radiation oncologist, stitches the plaque on the eye’s wall, covering the base of the tumor
- The specialist removes the breathing tube and places a bandage (or lead patch or glasses) over the patient’s eye
- Once treatment is over, the specialists will remove the plaque in a similar surgical procedure. During this surgery, the ophthalmologist may opt for laser treatment if necessary.
Risks & Complications
After surgery, the patient’s eyes may feel itchy or have the feeling of a foreign body in the eye. Eye movement and stitches may cause discomfort. Pain is rare, but should the patient experience it, the doctor will prescribe medication. When the bandage is removed for examination, the patient may have limited or double vision.
More side effects may include:
- Loss of eyelashes
- Redness in the eye
- Increased intraocular pressure
- Dry eye that refuses to go away
- Fatigue that may last several weeks
Risks and complications may arise because radiation can directly destroy cells in the body and later interfere with the cell division process. The damaged cells are incapable of metastasis and are regarded as sterile. The larger the tumor, the more the radiation, leading to more cell destruction. The rate of complication, however, depends on the location and size of the tumor.
Other risks and complications may include:
- Secondary glaucoma
- Clouding of the lens (cataracts) or radiation-induced cataract
- Vitreous humor and retinal detachment which may lead to loss of vision
- Scleral necrosis caused by inflammation and subsequent damage to scleral tissue
- Development of strabismus (misaligned eyes) due to damage of the extraocular muscles
- Radiation maculopathy or its subset, cystoid macular edema, which is treated with anti-VEGF intravitreal therapy
- Radiation retinopathy (damage to the retina), especially if the tumor is located close to the optic nerve and back of the eye. These effects may last for years after radiation.
- Vision loss which depends on the plaque's placement site. Vision loss may occur 12 to 18 months following radiation treatment. Eventually, most patients who undergo plaque brachytherapy lose vision in the place where the plaque was put.
Aftercare & Recovery
The patient stays in radioactive isolation in the hospital after surgery for a day or two. S/he remains in a room with limited visitors. Precautions are taken to protect those within the environment, such as pregnant women and children, who should stay 2 feet away from the patient.
A medical team visits the patient daily. They will remove the bandage two days after surgery and apply a cream in the eye to help prevent infection and reduce swelling. Patients are advised to stop scratching or rubbing the eye. They should also rest throughout the day and may resume a normal diet upon discharge.
The patient can be released from the hospital on the day the plaque is removed. The doctor places a bandage over the eye and prescribes eye drops, creams, and other medications. The patient must avoid wetting the bandage or patch.
The first follow-up visit takes place a month after the completion of treatment. Postoperative tests (such as blood tests, scans, etc.) may be conducted to check how the patient is responding to brachytherapy treatment.