Association Between Serum Testosterone Combined With Body Mass Index And Prognosis Of Prostate Cancer

【Background】Prostate cancer(PCa)is a male hormone-dependent disease that is common in middleaged and elderly men.It is currently considered one of the most common malignancies in men worldwide.The incidence of PCa accounts for about 10% of all cases of malignant tumors,second only to lung cancer.According to statistics,there are more than 1.2 million new cases of PCa and 350,000 PCa-related deaths worldwide each year.In China,due to population aging,changes in dietary structure,and the popularity of prostate-specific antigen(PSA)screening,the incidence and mortality of PCa have been increasing year by year.The 5-year survival rate of early localized PCa can be as high as 98% after systematic treatment.However,for some patients who experience recurrence or metastasis,the 5-year survival rate is only 30%.Currently,recurrent or metastatic PCa is still incurable.In clinical practice,it is particularly important to evaluate the prognosis of PCa patients and develop individualized treatment plans based on this to prolong their survival and improve their quality of life.Therefore,finding easily obtainable serum biomarkers and related indicators to personalize the prognosis evaluation of PCa patients and guide clinical treatment is of great significance.The occurrence and development of PCa are closely related to male hormones.Testosterone(serum testosterone,T)is the most important male hormone in the male body,which is crucial for maintaining the normal growth and development of the prostate.However,the specific relationship between testosterone and PCa is still not fully understood.It was previously believed that high levels of testosterone would increase the risk of PCa in men,while low levels of testosterone had a protective effect.However,more and more evidence recently suggests that low levels of serum testosterone are also associated with higher PCa incidence and malignancy,often indicating a poorer prognosis.All of these suggest that pre-treatment serum testosterone levels can be used as a factor in predicting PCa prognosis to a certain extent.However,previous studies have different definitions of low serum testosterone levels,so the international division of high and low serum testosterone levels has limited application value for Chinese patients.Body mass index(BMI)is a commonly used indicator for measuring the degree of obesity and whether or not one is healthy.Previous studies have shown that there is a certain linear relationship between BMI and serum testosterone levels in PCa patients.High BMI often indicates lower serum testosterone levels and poorer prognosis,suggesting that BMI can be used as one of the indicators for evaluating the prognosis of PCa patients.However,it is currently unclear whether serum testosterone combined with BMI can be used as a prognostic factor for PCa,and there are few related reports.In order to further explore the clinical significance of serum testosterone and BMI in predicting PCa prognosis,this study retrospectively collected data from 84 PCa patients,and analyzed the relationship between pre-treatment serum testosterone levels,BMI,and serum testosterone combined with BMI and PCa prognosis,providing relevant reference and theoretical basis for the prognosis evaluation and treatment plan selection of PCa patients.【Objective】Analyzing the relationship between serum testosterone levels,BMI,and the combination of serum testosterone and BMI on the prognosis of prostate cancer.【Methods】The study subjects were patients who visited the Department of Urology at the Second Affiliated Hospital of Guangzhou Medical University and were diagnosed with prostate cancer by prostate biopsy between June 2017 and June 2022.The final follow-up was conducted in January 2023.Relevant clinical data of the patients were collected and sorted.All study subjects had undergone androgen deprivation therapy(ADT).The patients were divided into two groups based on the international standard BMI and the occurrence of tumor progression during the follow-up period.Clinical data between the two groups were analyzed for differences,and corresponding statistical analyses were conducted.Progression-free survival(PFS)was defined as the time of tumor progression after ADT.Using PFS as the evaluation object,receiver operating characteristic(ROC)curves were drawn,and the maximum cutoff value for T/BMI was determined.The study subjects were divided into high T/BMI and low T/BMI groups,and Kaplan-Meier(KM)survival curves for T/BMI and PFS were generated and validated.Single-factor and multi-factor COX regression survival analyses were used to analyze variables between the two groups statistically,and to evaluate whether T,BMI,and T/BMI are independent risk factors for tumor progression or metastasis in PCa patients.【Results】1.According to the statistical analysis of BMI groups,the results showed that the serum testosterone level of the high BMI group was significantly lower than that of the non high BMI group,and the difference was statistically significant(P<0.0001).2.The clinical and pathological data of the two groups,which were divided into the tumor progression group and non-tumor progression group,were analyzed statistically.The results showed that there was no statistical difference in age,PSA,Gleason score,and smoking history between the two groups(P>0.05),but there was a statistical difference in BMI,T,T/BMI,and clinical staging(P<0.0001).3.The disease-free progression survival(PFS)was defined as the time from ADT treatment to tumor progression or metastasis in PCa patients.The receiver operating characteristic(ROC)curve was constructed with PFS as the evaluation object,and the area under the curve(AUC)of T/BMI value was 0.752(95% CI 0.670-0.836).According to the maximum Youden index of 0.526,the optimal cutoff value was 0.244,and 84 patients were further divided into a high T/BMI group(>0.244)with 35 cases and a low T/BMI group(≤0.244)with 49 cases.The statistical analysis of T/BMI in high and low groups showed that there was no significant difference in age,PSA,prostate volume,Gleason score,and smoking history between the two groups(P>0.05),but there was a statistical difference in BMI,T,and clinical staging(P<0.0001).4.The results of univariate COX regression analysis showed that BMI(HR=1.247,P=0.001),T(HR=0.936,P=0.009),T/BMI(HR=1.036,P=0.017),and metastasis(HR=1.593,P=0.025)were significantly correlated with the disease-free progression survival of prostate cancer after ADT treatment and had statistical significance.Age(HR=0.986,P=0.471),PSA(HR=1.000,P=0.709),prostate volume(HR=1.007,P=0.238),Gleason score(HR=1.164,P=0.229),and smoking history(HR=0.969,P=0.948)were not significantly correlated with the disease-free progression survival of prostate cancer after ADT treatment.5.Perform multiple-factor Cox regression analysis on the indicators with statistical differences in the single-factor Cox regression analysis.Considering the linear relationship between T,BMI,and T/BMI,T and BMI were removed.T/BMI and the presence or absence of metastasis were analyzed by multiple-factor Cox regression.The results showed that T/BMI(HR=1.037,P=0.015)and metastasis status(HR=1.312,P=0.482)were analyzed,indicating that T/BMI is an independent risk factor for tumor progression in PCa patients receiving ADT treatment.【Conclusions】1.The serum testosterone levels in PCa patients who experienced tumor progression were significantly lower than those who did not experience tumor progression.2.The BMI of PCa patients who experienced tumor progression were significantly higher than those who did not experience tumor progression.3.There is a certain correlation between serum testosterone,BMI,T/BMI,whether there is metastasis,and tumor progression.Among them,low T/BMI(HR=1.037,P=0.015)can be regarded as an independent risk factor for PCa progression.