Purchase this article with an account.
F. L. Munier, A. Balmer, H. Abouzeid, M. Beck-Popovic, M.-C. Gaillard, R. Moeckli, A. Pica; Second Line Conformal Stereotactic Radiotherapy for Macular and Papillary Retinoblastoma: A Step Towards Bone-Sparing Irradiation. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5261.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
For decades first line external beam radiotherapy (EBR) has been the treatment of choice in a majority of retinoblastoma (RB) cases. During the last 15 years, the trend has been to move away from EBR, mostly because of the devastating side effects on the bony orbit in terms of radiation-induced morbidity (cosmetic deformity) and mortality (mainly osteosarcoma), especially when delivered before 1 year of age. Management of advanced intraocular RB frequently requires EBR either as second line or salvage treatment. Stereotactic conformal radiotherapy (SCR) has been proposed to reduce the irradiation dose to the bony orbit. Our purpose was both to report our experience with SCR in RB, and to delineate the most beneficial indications to this new treatment modality.
In this study we report the preliminary results of 6 consecutive cases (7 eyes) treated by SCR at the Lausanne Retinoblastoma Clinic between 2005 and 2006. Target volumes and organs at risk were delineated by oncologists and ophthalmologists. Critical structures were contoured for treatment planning optimization and for dose volume histograms (DVH) evaluation. The treatment was planned with one isocenter and five static non-coplanar beams. A total dose of 50.4 Gy (1.8 Gy/fraction) was prescribed to the 90% isodose. Treatment was performed with a 6 MV photon beam and a micromultileaf collimator.
Follow-up ranged between 4 and 21 months (mean of 9.5 months). Complete tumor response was achieved in all eyes. When compared to conventional EBR, DVH parameters were consistent with smaller doses for all volumes of total cranial bone and other organs at risk. There were no acute or late side effects observed.
SCR for circumscribed tumors can be considered as a promising alternative to conventional EBR, as all bone volumes are relatively spared. SCR indications could specifically involve life-threatening (epipapillary) or vision-threatening (macular) residual tumors following chemoreduction and local treatment in group B and C eyes. We propose that residual epipapillary tumors are good indications to second line SCR, provided that the target volume can be restricted to the posterior pole, and as long as the eye is associated with the best visual potential. In case of residual macular tumor following chemoreduction and local treatment, SCR should be restricted to salvage therapy of foveal recurrence for the best eye only.
This PDF is available to Subscribers Only