[Stereotactic Rediosurgery for Uveal Melanoma; Postradiation Complications].

OBJECTIVE

The authors evaluate a group of patients with malignant uveal melanoma treated with stereotactic radiosurgery in the year. 2009-2011 on a linear accelerator LINAC.

MATERIAL AND METHODS

In 2009-2011 were followed 40 patients with malignant melanoma of the uvea in stage T2 and T3 treated with stereotactic radiosurgery (LINAC), the therapeutic dose of 35,0 Gy TD, TD max 42,0 Gy. We evaluated the influence of factors (age, exposure risk structures, time) to intraocular pressure (IOP) and temporal changes in intraocular pressure after surgery between the control group and the group of patients who underwent enucleation. The normality of data distribution was tested Shapiro-Wilk W test and graphically. The relations between the parameters were tested using simple and multiple linear regression (correlation coefficient r, the significance level p).

RESULTS

The mean age of the group of 40 patients with malignant melanoma of the uvea treated by one day session stereotactic radiosurgery on a linear accelerator in the year. 2009-2011 was 55.13±11.11 years. Average maximum radiation dose to sensitive structures has been the target of 12,0 Gy to the optic nerve and the ciliary 10,0 Gy. The analysis in our group confirmed that the prevalence of the tumor independent of sex, increasing with age, with most patients are diagnosed between 60 and 70 years of age. Analysis of the difference in intraocular pressure (IOP) before surgery showed no significant difference between the group of men and women (p=0.54). Using simple linear regression, we confirmed assumptions, related to IOP before stereotactic radiosurgery with age (r=-0.09, p=0.65). Multiple linear regression, we evaluated the relationship between predictors (dose at-risk structures--lens and optic nerve) and the change in IOP from the value before stereotactic radiosurgery at each time interval. Relations between predictors (Dose aperture--L, the dose of the optic nerve--O) and IOP of the file being described partial correlation coefficients after 2 weeks. For the relationship is significant correlation between the dose and the IOP in the lens at the time of 1 year, 1.5 years, and 2 years after the stereotactic radiosurgery.

CONCLUSION

A single stereotactic radiosurgery on a linear accelerator LINAC is possible at a dose of 35,0 to 38,0 Gy in intraocular melanomas in stage T1 to T3. According to our results, this is a highly effective method of treatment of uveal melanomas elevation to 6 mm and a capacity of up to 0,4 cm3. Secondary glaucoma is one of the most serious causes of enucleation after one day session stereotactic radiosurgery at linear accelerator (LINAC) for uveal melanoma. The percentage of enucleation in our investigated group (17.5%) for secondary glaucoma is about the same as in other studies.