Positive Association between Basal Total Testosterone Circulating Levels and Tumor Grade Groups at the Time of Diagnosis of Prostate Cancer

Introduction: To test the hypothesis that basal total testosterone (TT) levels are associated with International Society of Urologic Pathology (ISUP) tumor grade groups at the time of diagnosis of prostate cancer (PCA). Methods: From November 2014 to March 2018, preoperative TT and PSA were measured in 601 consecutive patients who were not under androgen deprivation and undergoing surgery for PCA. Patients were classified into low (ISUP 1; reference group), intermediate (ISUP 2/3), and high (ISUP 4/5) tumor grade groups. The association of TT and other clinical factors with tumor groups was evaluated by multinomial multivariate regression analysis. Results: 218 patients (36.3%) were biopsy low grade (ISUP 1), 297 (49.4%) intermediate grade (ISUP 2/3), and 86 (14.3) high grade (ISUP 4/5). Median basal circulating TT levels progressively increased as tumor grade groups increased. On multivariate models, TT, among other clinical factors, was positively associated with the risk of intermediate (OR 1.001; p = 0.023) and high tumor grades (OR 1.002, p = 0.022) compared to low-grade cancers. Conclusions: Increased endogenous circulating basal TT levels were positively associated with ISUP tumor grade groups at the time of diagnosis indicating a close association with tumor biology. Basal TT levels may reflect the heterogeneity of the cancer population.