Background:Rapid visual acuity (VA) decline was a common complaint in patients with sellar/suprasellar germinoma.In our hospital,3.4 Gy/2f of emergency irradiation was applied to save patient VA and enable subsequent chemoradiotherapy.This study aimed to investigate the efficacy of emergency irradiation with 3.4 Gy/2f in patients with sellar/suprasellar germinoma who had rapid VA decline.Methods:From January 2014 to December 2017,33 patients with sellar/suprasellar germinoma who complained of VA decline within 3 months received 3.4 Gy/2f of emergency irradiation in Beijing Tiantan Hospital.The best-corrected VA (BCVA) and mean deviation (MD) were measured.Correlations between visual function change and clinical factors,including age at diagnosis,duration of VA decline,extent of tumor regression,serum level of tumor markers,were analyzed.Results:Among 33 patients with sellar/suprasellar germinoma,the median diameter and volume of sellar/suprasellar lesions were 32 mm (range:5-55 mm) and 12.9 cm3 (range 0.6-58.5 cm3),respectively.Data on pre-and post-emergency-irradiation BCVA were obtained in 32 patients.For the right eyes,BCVA was improved in 23 patients (71.9％),unchanged in 7 (21.9％),and worsened in 2 (6.2％);and for the left eyes,these numbers were 27 (84.4％),4 (12.5％),and 1 (3.1％),respectively.In terms of the logarithm of the minimum angle of resolution (logarithm of the minimum angle of resolution =Log (1/BCVA) score,the improvement was significant in both eyes (P ＜ 0.001).In terms of MD,six patients had paired data and the improvement was marginal in the right eyes (P =0.068) and significant in the left eyes (P =0.043).However,no clinical factor was found to have correlation with visual function improvement.Conclusion:In sellar/suprasellar germinoma patients with VA decline,3.4 Gy/2f of emergency irradiation was effective in improving visual function.