Local chemotherapy in cases of ocular tumors
Moataz Mohamed Mostafa Fathy Dabees;
Abstract
Ocular oncology consists of a broad spectrum of benign and malignant lesions of the eye and adnexa that can lead to visual loss or even loss of life.
Tumors discussed in our essay are those that can be treated with local chemotherapy. These tumors are capillary hemangiomas, choroidal hemangioma, tumors of conjunctiva and cornea (Stratified squamous neoplasia and melanocytic tumors), retinoblastoma and PIOL.
Ocular tumors may be asymptomatic or its symptoms may range from non-specific symptoms like ocular pain, redness and discharge to visual loss from tumor growth. Other symptoms may be strabismus or leucocoria.
Effective management of ocular tumors depends on accurate diagnosis which is not only clinically but also with investigative techniques like B-scan, OCT, FFA, CT scan, MRI and biopsy.
Treatment of ocular tumors aims to save patients life mainly and save vision if possible.
Treatment modalities can range from observation and follow up to surgery. Surgery can range from excision of the tumor with safety margin up to enucleation. Radiation therapy can be used either external beam radiation or plaque radiotherapy. Cryotherapy also can be used. Chemotherapy is one of the modalities of treatment of ocular tumors. It can be either oral as beta blockers for hemangiomas or intravenous infusion as CEV regimen for retinoblastoma for example.
Chemotherapy is the term given for the use of chemical substances in treatment of cancer. It may be given for curative intent or to reduce symptoms and prolong life (palliative). It can be used alone or with the aid of other treatment modalities.
Chemotherapeutic agents act by killing cells that divide rapidly (main property of cancer cells).In broad sense they work by impairing mitosis by various mechanisms including damaging DNA or the cell machinery involved in cell division. There are various types of chemotherapeutic agents with different mechanisms of action. They include alkylating agents as thioTEPA, antimetabolites as methotrexates, anti-microtubules as vincristine, topoisomerase inhibitors as etoposide, and cytotoxic antibiotics as Mitomycin.
There is more than one strategy in using chemotherapy. It can be given solely or combined with other modalities. It may be used as first line of treatment (induction) or after remission (consolidation). Combination of agents is used to minimize resistance to one agent and lower doses and to decrease side effects.
By the mechanism of action of chemotherapy it can affect normal cells and harm the normal cells that divide rapidly causing myelosuppression, immunosuppression, mucositis and alopecia.
Intraocular tumors are difficult to treat with systemic chemotherapy because of blood retinal barrier and small size of the eye; high doses of drugs have to be injected intravenously to achieve therapeutic doses.
So in a way to increase effect of chemotherapeutic agents and to decrease its side effects ocular oncologists and scientists were performing experiments on the local use of these agents on tumors. Carboplatin has been injected intravitreal, Subconjuctival and subtenon or by using CCI for treatment of retinoblastoma. ThioTEPA was injected intrathecal and intravitreal in treatment of retinoblastoma and PIOL. Melphalan was used by intravitreal injections or by irrigation during vitrectomy or even by intra-arterial injection (in ophthalmic artery) for treatment of retinoblastoma. Methotrexate is used in treatment of PIOL and PCNSL. It is injected either intravitreal or intrathecal. Mitomycin can be used in the form of eye drops for treatment of corneo-conjunctival intraepithelial neoplasia as adjuvant or primary therapy in some cases. Also it can be used for invasive squamous carcinoma of the conjunctiva as adjuvant therapy with surgery. It can be used as a primary treatment for PAMa and as adjuvant treatment in conjunctival melanoma. It is used in treatment of sebaceous carcinoma. 5-FU is used in treatment of squamous lesions either intraepithelial or invasive lesions. For ocular tumors it can be used in form of drops. IFNs are used in the form of topical drops, Subconjuctival or perilesional for treatment of OSSN or melanocytic lesions of conjunctiva (CM and PAMa). Bevacizumab is used in the form of intravitreal injections for circumscribed choroidal hemangioma. Beta blockers can be used topically or intralesional for treatment of hemangiomas.
Researchers are constantly developing new methods of drug delivery and other therapies. Promising areas of future research include genetics, targeted therapies, and immunotherapies. Identifying gene changes and triggers may provide specific targets for more precise treatment.
Tumors discussed in our essay are those that can be treated with local chemotherapy. These tumors are capillary hemangiomas, choroidal hemangioma, tumors of conjunctiva and cornea (Stratified squamous neoplasia and melanocytic tumors), retinoblastoma and PIOL.
Ocular tumors may be asymptomatic or its symptoms may range from non-specific symptoms like ocular pain, redness and discharge to visual loss from tumor growth. Other symptoms may be strabismus or leucocoria.
Effective management of ocular tumors depends on accurate diagnosis which is not only clinically but also with investigative techniques like B-scan, OCT, FFA, CT scan, MRI and biopsy.
Treatment of ocular tumors aims to save patients life mainly and save vision if possible.
Treatment modalities can range from observation and follow up to surgery. Surgery can range from excision of the tumor with safety margin up to enucleation. Radiation therapy can be used either external beam radiation or plaque radiotherapy. Cryotherapy also can be used. Chemotherapy is one of the modalities of treatment of ocular tumors. It can be either oral as beta blockers for hemangiomas or intravenous infusion as CEV regimen for retinoblastoma for example.
Chemotherapy is the term given for the use of chemical substances in treatment of cancer. It may be given for curative intent or to reduce symptoms and prolong life (palliative). It can be used alone or with the aid of other treatment modalities.
Chemotherapeutic agents act by killing cells that divide rapidly (main property of cancer cells).In broad sense they work by impairing mitosis by various mechanisms including damaging DNA or the cell machinery involved in cell division. There are various types of chemotherapeutic agents with different mechanisms of action. They include alkylating agents as thioTEPA, antimetabolites as methotrexates, anti-microtubules as vincristine, topoisomerase inhibitors as etoposide, and cytotoxic antibiotics as Mitomycin.
There is more than one strategy in using chemotherapy. It can be given solely or combined with other modalities. It may be used as first line of treatment (induction) or after remission (consolidation). Combination of agents is used to minimize resistance to one agent and lower doses and to decrease side effects.
By the mechanism of action of chemotherapy it can affect normal cells and harm the normal cells that divide rapidly causing myelosuppression, immunosuppression, mucositis and alopecia.
Intraocular tumors are difficult to treat with systemic chemotherapy because of blood retinal barrier and small size of the eye; high doses of drugs have to be injected intravenously to achieve therapeutic doses.
So in a way to increase effect of chemotherapeutic agents and to decrease its side effects ocular oncologists and scientists were performing experiments on the local use of these agents on tumors. Carboplatin has been injected intravitreal, Subconjuctival and subtenon or by using CCI for treatment of retinoblastoma. ThioTEPA was injected intrathecal and intravitreal in treatment of retinoblastoma and PIOL. Melphalan was used by intravitreal injections or by irrigation during vitrectomy or even by intra-arterial injection (in ophthalmic artery) for treatment of retinoblastoma. Methotrexate is used in treatment of PIOL and PCNSL. It is injected either intravitreal or intrathecal. Mitomycin can be used in the form of eye drops for treatment of corneo-conjunctival intraepithelial neoplasia as adjuvant or primary therapy in some cases. Also it can be used for invasive squamous carcinoma of the conjunctiva as adjuvant therapy with surgery. It can be used as a primary treatment for PAMa and as adjuvant treatment in conjunctival melanoma. It is used in treatment of sebaceous carcinoma. 5-FU is used in treatment of squamous lesions either intraepithelial or invasive lesions. For ocular tumors it can be used in form of drops. IFNs are used in the form of topical drops, Subconjuctival or perilesional for treatment of OSSN or melanocytic lesions of conjunctiva (CM and PAMa). Bevacizumab is used in the form of intravitreal injections for circumscribed choroidal hemangioma. Beta blockers can be used topically or intralesional for treatment of hemangiomas.
Researchers are constantly developing new methods of drug delivery and other therapies. Promising areas of future research include genetics, targeted therapies, and immunotherapies. Identifying gene changes and triggers may provide specific targets for more precise treatment.
Other data
| Title | Local chemotherapy in cases of ocular tumors | Other Titles | العلاج الكيميائي الموضعي في حالات أورام العين | Authors | Moataz Mohamed Mostafa Fathy Dabees | Issue Date | 2015 |
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