Exploring The Risk And Prognostic Factors Of Second Primary Prostate Cancer Based On SEER Database

Background and ObjectiveWith the increase of the incidence and survival rate of cancer around the world,the risk of second primary Prostate Cancer(sp PCa)in male patients increases,sp PCa may be caused by aging,the same cancer risk factors,and radiation therapy for the first primary cancer.However,the clinicopathological features,treatment measures and prognostic risk factors of sp PCa have not been fully clarified.The purpose of this study was to analyze the survival outcome of sp PC,to explore the risk and prognostic factors of sp PCa,to determine the best treatment,and to develop and validate prognostic nomograms for predicting overall survival(OS)and cancer-specific survival(CSS)in patients with sp PCa.Material and MethodBased on the Surveillance,Epidemiology,and End Result(SEER)database,patients diagnosed with sp PCa from 2004 to 2015 were enrolled in this retrospective analysis.The clinical characteristics and causes of death(COD)of these patients were analyzed;Kaplan-Meier(KM)survival analysis and log-rank test were used to explore the survival differences of different primary cancer and treatment;Gray’s test was used to compare the cumulative incidence function(CIF)of competitive risk accumulation rate of different treatment.With the method of random-number generation,the patients were divided into the training cohort and the verification group.Subsequently,univariate COX regression analyses,Lasso regression and multivariate COX regression analyses were used to screen prognostic risk factors.Nomograms were constructed to predict 3‐and 5‐year OS and CSS based on the final results.Finally,the Harrell’s C index(Harrell’s concordance index),the receiver operator characteristic(ROC)curves,the area under the curve(AUC)and the calibration plots were used to evaluate nomograms performance.Result1.The most common primary cancers in patients with sp PCa are bladder cancer(27.75%),colon cancer(11.46%),cutaneous melanoma(10.90%),renal and renal pelvis cancer(8.63%),non-Hodgkin’s lymphoma(6.35%)and lung cancer(5.01%).2.Compared with prostate cancer,sp PCa patients are more likely to die of bladder cancer,colorectal cancer,lung cancer,renal and renal pelvis cancer and non-Hodgkin’s lymphoma,and the prognosis of bladder cancer and lung cancer is poor.3.Radiotherapy not only reduces the risk of dying from primary cancer and prostate cancer,but also prolongs the survival time of patients;surgery reduces the risk of dying from prostate cancer but increases the risk of dying from primary cancer,and does not increase the survival time of patients;chemotherapy increases the risk of dying from prostate cancer and reduces the survival time of patients..4.The prognostic factors associated with OS were primary cancer location,Gleason score,PSA,age,radiotherapy and marital status,while the prognostic factors associated with CSS were TNM stage,surgery,Gleason score,PSA and radiotherapy.5.The prognostic nomograms for predicting the survival rates of OS and CSS in patients with sp PCa have good performance.ConclusionThe first primary cancer is an important cause of death in patients with sp PCa,and it is necessary to take active treatment measures such as radiotherapy for patients with sp PCa.We established a predictive model for predicting OS and CSS in patients with sp PCa,nd these two models have good performance.