Comparison of Gleason scoring and the new Grade-Group System in prostate cancers: a 15-year retrospective study

Aim: Prostate cancer (PC) is the most common malignant tumour in men. The most widely used histological grading scheme for PC is Gleason scoring (GS). After the original, this system has been modified several times. In this study, we retrospectively investigated the new Grade-Group system (GGS). Methods: This study includes 486 cases diagnosed with PC between 2000 and 2015. All cases were re-grouped for the new GGS system and its relationship with prognosis was examined. Results: GGS subgroups had a statistically significant relationship between prognostic factors and this relationship was more significant between GGS 2 and GGS 3 [tumor status (p <0.001), age (p = 0.045), PN invasion (p <0.001), stage (p = 0.004), and LN status (p <0.001)]. In univariable survival analysis, there was a significant difference between GGS subgroups (for GGS 2-GGS 3, RFS: p = 0.035 and OS: p = 0.012; for GGS 4-GGS 5, RFS: p = 0.001 and OS: p = 0.001). In multivariable survival analysis, GGS subgroups were found to be an independent survival parameter for PC (for GGS 2-GGS 3, OS: HR = 2.56, p = 0.012 and RFS: HR = 2.69, p = 0.038; for GGS 4-GGS 5, OS: HR = 2.84, p = 0.011 and RFS: HR = 2.59, p < 0.001). Conclusions: According to our results, the new GGS performs the prognostic risk grading more accurately than the old classification. Also, the fact that this system contains fewer categories and is simpler has increased the interobserver compatibility. Keywords: Grade-group system, Gleason scoring, prostate cancer. OZ Amac: Prostat kanseri (PK) erkeklerde en sik gorulen malign tumordur. PK icin en yaygin kullanilan histolojik derecelendirme semasi Gleason skorlamasidir (GS). Orijinalinden sonra bu sistem birkac kez degistirildi. Bu calismada, PK icin tanimlanan yeni Grade-Group sistemini (GGS) geriye donuk olarak inceledik. Yontemler: Bu calisma 2000-2015 yillari arasinda PK tanisi konmus 486 vakayi icermektedir. Tum olgular yeni GGS sistemi icin yeniden gruplandirildi ve prognozla iliskisi incelendi. Bulgular: GGS alt gruplarinin prognostik faktorler arasinda istatistiksel olarak anlamli bir iliski vardi ve bu iliski GGS 2 ve GGS 3 arasinda daha anlamli idi [tumor durumu (p <0.001), yas (p = 0.045), PN invazyonu (p <0.001), evre (p = 0.004), ve LN durumu (p <0.001)]. Tek degiskenli sagkalim analizinde GGS alt gruplari arasinda anlamli bir fark vardi (GGS 2-GGS 3, RFS: p = 0.035 ve OS: p = 0.012; GGS 4-GGS 5, RFS icin: p = 0.001 ve OS: p = 0.001). Cok degiskenli sagkalim analizinde GGS alt gruplarinin PK icin bagimsiz bir sagkalim parametresi oldugu bulundu (GGS 2-GGS 3, OS: HR = 2.56, p = 0.012 ve RFS: HR = 2.69, p = 0.038; GGS 4- icin GGS 5, OS: HR = 2.84, p = 0.011 ve RFS: HR = 2.59, p <0.001). Sonuclar: Calismamiza gore, yeni GGS sistemi prognostik risk siniflandirmasini eski siniflandirmadan daha dogru bir sekilde gerceklestirmektedir. Ayrica, bu sistemin daha az kategori icermesi ve daha basit olmasi, gozlemciler arasi uyumlulugu artirdi. Anahtar Kelimeler: Grade-grup sistemi, gleason skorlamasi, prostat kanseri.