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R.M. Awdeh, R.D. Drewry, N.C. Kerr, B.G. Haik, S. Wu, X. Xiong, T.E. Merchant; Visual Outcome After Conformal Radiation Therapy in Children with Optic Pathway Glioma . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2232.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: The purpose of the study was to develop a model to predict visual outcome after conformal radiation therapy (CRT) in children with optic pathway glioma (OPG). Methods: Twenty-two children (median age 9.4 years) with OPG were treated on a prospective trial of CRT between 7/1997 and 2/2002 at St. Jude Children's Research Hospital. Visual acuity (VA) was assessed from the time of diagnosis and serially after radiation therapy. Nine patients received chemotherapy to delay or avoid CRT and nine underwent surgical debulking prior to CRT. The median time from diagnosis to CRT in the chemotherapy group was 58 months compared to 2 months for the patients who did not receive chemotherapy. All patients received 54 Gy in 30 fractions to a volume encompassing the tumor with a 1.0 cm clinical target volume. The goal of the analysis was to estimate VA at the time of CRT (intercept) and longitudinal change after CRT (slope) and to determine the influence of chemotherapy and surgery on the intercept and slope. A mixed effects (random and fixed effects) model was used for the analysis with VA, converted to logMAR, as the response variable. Median follow-up was 24 months after the start of CRT. Results: Patients treated with chemotherapy had significantly worse VA at the start of CRT compared to those who did not receive chemotherapy [logMAR chemotherapy vs. no chemotherapy] OD: 1.9737 vs 0.7374 (p=0.0268) and OS: 1.4908 vs. 0.5774 (p=0.0764). VA declined significantly OS (positive slope) in those who received chemotherapy compared to those who did not receive chemotherapy [logMAR/month chemotherapy vs. no chemotherapy] 0.009270 vs. -0.00209 (p=0.0468). Patients who underwent a single surgery procedure prior to CRT had significantly better VA at the start of CRT compared to those who did not [logMAR surgery vs. no surgery] OD: 0.7484 vs. 2.1182 (p=0.0331) and OS: 0.6891 vs. 1.3944 (p=0.2648). There was no difference in change over time based on surgery. Discussion: In young children with optic pathway tumors, radiation is often delayed for fear of side effects involving endocrine and cognitive function. Children who delay irradiation are likely to have poorer VA if they receive chemotherapy or delay irradiation until further progression is documented. CRT, planned soon after diagnosis, results in stable or improved vision in most patients. Surgical decompression prior to irradiation may have a role in selected cases.
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