|Year : 1982 | Volume
| Issue : 4 | Page : 233-235
Radiotherapy in ocular tumours
Dept. of Radiotherapy & Diagnosis, Tata Memorial Hospital Parel, Mumbai, India
J M Pinto
Dept. of Radiotherapy & Diagnosis, Tata Memorial Hospital Parel, Mumbai
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Pinto J M. Radiotherapy in ocular tumours. Indian J Ophthalmol 1982;30:233-5
Ocular tumours at the Tata Memorial Hospital are rare. For any particular year they form only about 0.14% of the total proved cancer cases.
The great majority are retinoblastomas occurring before the age of 5 years and they present in various ways. Only a few carcinomas of the bulbar conjunctiva are seen, malignant melanomas are very rare.
Radiotherapy has an important role in these tumours, in the early cases it can be curative, in the late, useful palliation may be obtained.
| Materials and methods|| |
In the period 197 1-75 there were altogether 139 ocular tumours, in a total of 40,603 cancer cases.
There were 127 retinoblastomas, 7 carcinomas of the bulbar conjunctiva and 5 cancers of unspecified nature [Table - 1]. The bilateral cases, show lower average age, and confirms the impression that these are genetically determined [Figure - 1]. Tumour was unilateral in 91 cases and bilateral in 36 cence 75 cases were in males 52 in females.
Their presentation varied from small lesions unilaterally, to huge fungating growths, some of which were recurrent after surgery. The cases presenting with bilateral disease had usually some vision in the less affected eye.
For radiotherapy supervoltage is essential with the Cobalt beam or Linear Accelerator. Where an attempt is made to preserve vision an anterior direct field is used with or without sedation to a tumour dose of approximately 3,500 to 4,000 rad in about 4 weeks. With deep x-rays lateral fields are essential. Where the whole orbit is irradiated, post-operatively an anterior and a lateral field are used of the order of 5 x 5 cms. For palliative treatment, larger fields are used with proportionately smaller doses.
In certain circumstances, an implant may be advisable either Cobalt 60 or Gold 198 grain--the dose at the apex of the tumour is about 4,000 rad while the base at the sclera receives about 10,000 rad.
For carcinoma of the conjunctiva small lesions can be treated with beta radiation (Strontium plaque) - the dose is 2,000 rad weekly for about 4 to 5 weeks. Larger lesions will require post-operative supervoltage radiation.
Malignant melanoma of the uveal tract is treated essentially in the same manner as a retinoblastoma.
One big factor in this is the large number of cases that are lost to follow-up and are counted as dead.
| Discussion|| |
Retinoblastomas are uncommon tumours, the frequency in our Institution is about 0.14% of all tumours but this is because we see a very large number of other cancers. However, its treatment has to be carried out with a certain amount of circumspection. Since often the question of vision is uppermost in the minds of all concerned, radiotherapy has an important role, surgical measures such as photo-coagulation and cryotherapy are also possible in certain circumstances but the role of chemotherapy is apparently not clearly defi tied. About two decades age TEM was strongly advocated. Now Vincristine and cyclo phosphamide have been shown to have a beneficial effect particularly in micro-metastases.
Unilateral cases presenting initially are usually advised enucleation provided other eye is not non-s-eing for any reason as the diagnosis may sometimes be in doubt. If vision is fair and the parents are against surgery then an attempt is made to preserve vision in that eye even if the other eye is normal. After enucleation if the specimen shows no extension to the optic nerve cut end and there is no peribulbar extension or to choroid or emissaries only observation is advised If the optic nerve is involved and/or peribulbar tissues then post-operative irradiation is given to the whole orbit. If the lesion is extensive and peribulbar tissues are involved initially then exenteration is done.
In bilateral retinoblastoma the more affected eye is enucleated and an attempt made to preserve vision in the other eye. Treatment in such cases is with a Cobalt beam a direct anterior field is used and a tumour dose of 3500 to 4000 given in about 4 weeks and of course a cataract that may develop has to be taken care of.
With deep x-rays sparing of tissues anterior ly is not possible and lateral and/or medial fields are nsed. For post-operative treatment, the whole orbit is irradiated with anterior and lateral fields preferably with supervoltage.
Treatment of carcinoma of the conjunctiva depends mainly upon the site and size of the lesion, early lesions can be excised and irradiated post-operatively with Beta radiation (Strontium), larger lesions may require enucleation or exenteration followed by irradiation with supervoltage Irradiation (damage).
Post irradiation sarcomas sometimes develop many years, about 10 or more later but these only occur if very large doses have been given and irradiation is repeated for recurrences. There were none in this series.
Follow-up of all cases is essential, particularly in the unilateral ones where the opposite eye can be observed by fundoscopic and other examination, so that the earliest lesion can be treated adequately by irradiation, photocoagulation or cryotherapy as the situation demands.
In conclusion, it can be stated that radiotherapy has a very important role in the management of retinoblastoma in the early cases it can be curative and in the late cases useful palliation may be obtained.
[Figure - 1]
[Table - 1]