Characteristics and risk differences of different tumor size on localized prostate cancer: A retrospective cohort study in the SEER database

OBJECTIVE: We aimed to evaluate the role of tumor size in predicting tumor risk for localized prostate cancer (PCa) patients undergoing radical prostatectomy (RP). METHODS: Twenty‐five thousand, one hundred twenty‐seven men with PCa receiving RP from 2010 to 2015 were extracted from the Surveillance, Epidemiology, and End Results database. Kaplan–Meier plots and multivariable Cox regression analyses were used to illustrate overall survival (OS) according to the tumor size. The tumor size was confirmed by postoperative pathology after RP. RESULTS: Among overall localized PCa, 84.6% were high‐risk PCa, 9.2% were intermediate‐risk PCa, and 6.2% were low‐risk PCa. Multivariate analyses demonstrated that tumor size ≥21 mm was an independent risk predict factor of low‐risk PCa (odds ratio [OR]: 11.940; 95% CI, 9.404–15.161; p < 0.001) and intermediate‐risk PCa (OR: 1.887; 95% CI, 1.586–2.245; p < 0.001). Tumor sizes ≤5 mm significantly correlated with high‐risk PCa (p < 0.001). Tumor size ≤5 mm had the worst OS in overall localized PCa and high‐risk PCa (p < 0.001). CONCLUSIONS: In localized PCa, tumor sizes ≥21 mm may help predict low or intermediate‐risk PCa, while tumor sizes ≤5 mm might help predict high‐risk PCa. In clinical practice, we should be on high alert for patients with tumors size ≤5 mm due to its poor prognosis after RP.