Objective To evaluate the clinical characteristics and outcomes of patients with Gleason score 10 prostate cancer treated by external radiotherapy and hormone therapy. Methods From January 2003 to March 2014, 1832 patients with prostate cancer were treated, among which 9 patients(represented 0.49%) were identified as Gleason score 10 disease on prostate core biopsy without distant metastases when first diagnosed. All 9 patients were treated by whole pelvic external radiotherapy(The whole pelvic dose was 50.0 Gy and the boost dose ranged from 76.2 to 78.0 Gy) and long-term hormone therapy. We assessed the clinical characteristics, treatment outcomes and treatment toxicities. Survival curves were calculated using the Kaplan-Meier method. Results The median follow-up was 4.8 years. Six patients’ pre-treatment prostate-specific antigen(PSA) levels were lower than 20.0 μg/L and three patients’ pre-treatment PSA levels were higher than 70.0 μg/L. The median percentage of positive biopsy cores was 91%. Three, four and two cases were classified as T2 c, T3 a and T3 b stage, respectively. Three cases were assessed as N1 stage. The 5-year biochemical failure-free survival, distant metastasis-free survival, cancer specific survival and overall survival rates were 28.6%, 57.1%, 66.7% and 57.1%, respectively. Five patients experienced grade 1-2 acute gastrointestinal toxicities and six patients complained of grade 1-2 acute genitourinary toxicities. No bone fracture or cardiovascular disease was detected. Conclusions Gleason score 10 prostate cancer on core biopsy is usually combined with other high risk factors. The pre-treatment PSA levels lie in two extremes. Timely and active treatments are urgent needed because unfavourable oncological outcomes are often presented. Objective To evaluate the clinical characteristics and outcomes of patients with Gleason score 10 prostate cancer treated by external radiotherapy and hormone therapy. Methods From January 2003 to March 2014, 1832 patients with prostate cancer were treated, among which 9 patients (represented 0.49%) were identified as Gleason score 10 disease on prostate core biopsy without distant metastases when first diagnosed. All 9 patients were treated by whole pelvic external radiotherapy (The whole pelvic dose was 50.0 Gy and the boost dose ranged from 76.2 to 78.0 Gy) and long-term Hormone therapy. We assessed the clinical characteristics, treatment outcomes and treatment toxicities. Survival curves were calculated using the Kaplan-Meier method. Results The median follow-up was 4.8 years. Six patients’ pre-treatment prostate-specific antigen (PSA) levels were lower than 20.0 μg / L and three patients’ pre-treatment PSA levels were higher than 70.0 μg / L. The median percentage of positive biopsy co Res was 91%. Three, four and two cases were classified as T2 c, T3 a and T3 b stage, respectively. Three cases were assessed as N1 stage. The 5-year biochemical failure-free survival, distant metastasis-free survival, Five patients experienced grade 1-2 acute gastrointestinal toxicities and six patients complained of grade 1-2 acute genitourinary toxicities. No bone fracture or cardiovascular disease was detected. Conclusions Gleason score 10 prostate cancer on core biopsy is usually combined with other high risk factors. The pre-treatment PSA levels lie in two extremes. Timely and active treatments are urgent needed because unfavorable oncological outcomes are often presented.