domingo, 25 de noviembre de 2018

Eye cancer treatment

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

Eye cancers are treated by a team of specialists and doctors. This is called a multidisciplinary team approach.

The team includes an ophthalmologist or eye doctor, an oncologist, radiation oncologist or cancer specialist and others.

The primary aim of therapy is to prevent spread, stop growth and remove the tumor while trying to preserve eyesight.

Specific therapy for Intraocular melanoma, Intraocular lymphoma & other eye cancers (1, 2, 3, 4) –

Monitoring the growth of the tumor – If the tumor is small or slow growing the physician may recommend a wait and watch approach.
This is useful in old and ill patients who have few eye symptoms and in who therapy would be more inconvenient due to side effects. Once the tumor is thicker than 2-3mm or larger than 10 mm in diameter an active therapy may be started.
Surgery – This includes removal of the tumor and its surrounding tissues. Surgery is not helpful in eye lymphomas. Surgery for eye melanoma is done by an ophthalmologist, usually under the microscope. Patient is usually made unconscious and is under general anaesthesia. Types of surgery includes:
1. Part or all of the iris may be removed (iridectomy). Sometimes a small piece of the outer part of the eyeball called trabeculae is removed (Iridotrabeculectomy). The iris and ciliary body may be removed (Iridocyclectomy)
2. Resectomy or removal of the melanoma of the ciliary body or choroid.
3. The whole eye may be removed (eneucleation) in cases of large and advanced tumors. Cosmetic surgery to fill in the empty socket may be opted by many patients. When the whole eye is removed there is a chance of the tumor coming back in the orbit especially if it is very aggressive form of cancer.
Radiation therapy – A disc that releases radiation may be placed within the eye after surgery. This releases radiation that prevents recurrence of the tumor. This is called brachytherapy.
Radiation uses high-energy x-rays, proton beams and gamma rays to kill the cancer.
Radiation may also be given by an external beam via a machine. Proton beam therapy uses a cyclotron that directs a proton radiation beam to the affected eye and spares the surrounding healthy tissues leading to lower side effects.
Side effects of radiation include cataracts, dry eyes, loss of hair around the eyes and eyelashes, retinal damage (retinopathy), optic nerve damage (neuropathy), glaucoma (abnormal pressure within the eye) etc. For eye lymphomas radiation to both eyes may be needed. Sometimes brain and spinal cord may also need irradiation.
Stereotactic radiosurgery – This is radiation therapy done with a Gamma beam or gamma knife to resect or remove the tumor.
Laser therapy – This uses a laser beam to shrink a smaller tumor. This is known as thermotherapy or transpupillary thermotherapy (TTT). Laser therapy is sometimes used in combination with radiotherapy.
Laser photocoagulation uses focussed high energy laser beams to burn the tumor tissue. It is not much used for eye melanomas but may be effective for small melanomas.
Chemotherapy - This involves use of anti-cancer drugs that are injected or taken as pills. This is useful in eye lymphomas as well. Methotrexate is a common drug used in eye lymphomas.
Drugs may also be injected directly into the affected eye or given via the spinal cord. In this manner, more of the drug reaches the site of the cancer. These are given in cycles of around 3 to 4 weeks. Common side effects include hair loss, nausea, vomiting, diarrhea, infections, bleeding tendencies, bone marrow suppression, fatigue etc.
Supportive care or end of life care – This includes treatment to relieve a person’s discomfort due to side effects of therapy. This may be given at any stage of the cancer. It is especially important at more advanced stages of the disease.
Failure of therapy or recurrence of cancer – These patients need a different approach or sometimes if there is complete failure to respond to therapy they may need end of life care or hospice care. If the recurrence is intraocular, eneucleation may be considered. If the recurrence is extraocular leading to metastasis, chemotherapy may be chosen as an option.
Monoclonal antibodies may be given in eye lymphomas. Some agents are Rituximab, ibritumomab tiuxetan, tositumomab etc. These may be given in combination with other chemotherapy agents.
Retinoblastoma is usually eye cancer that affects children. Aim of therapy is to remove the tumor, preserve vision as much as possible and prevent recurrence. Therapy includes chemotherapy, radiation and surgery. However, eneucleation is for patients who have severe disease in one eye and there is no hope of residual vision in the affected eye. (5)
Eyelid and other adnexal tumors and cancer are usually similar to skin cancers. The main therapy option is removal of the cancer by surgery. Various types of surgery like cryosurgery, Moh’s surgery or biopsy are undertaken. These intend to remove the tumor and attempt to reconstruct the eyelid.
More advanced cancers may require removal of the eye or eneucleation, chemotherapy and radiation therapy. In metastatic eyelid cancers chemotherapy, radiation therapy, more extensive surgery and other options may be considered. Immunotherapy and palliative care may be offered to these patients. (6)

Complementary and Alternative therapies –

Usually Complementary or Alternative therapies are suggested by family and friends of cancer patients. While Complementary therapy often goes alongside regular medical therapy, Alternative therapies are chosen instead of prescribed medical therapy.

Complementary therapies include meditation, stress relieving therapies and exercises, some herbal teas etc. for chemotherapy induced nausea, acupuncture etc. Some of these are harmless except for the fact that they make the patient feel better.

Alternative therapies are offered as cures for cancers and may often do more harm than good sometimes wasting precious time and allowing the cancer to grow so therapy becomes less effective.