Investigative clinical study on prostate cancer part VI: Follicle-stimulating hormone and the pituitary-testicular-prostate axis at the time of initial diagnosis and subsequent cluster selection of the patient population

Abstract

Aim: To evaluate the physiopathology of follicle-stimulating hormone (FSH) along the pituitary-testicular-prostate axis at the time of initial diagnosis of prostate cancer in relation to the available clinical variables and to the subsequent cluster selection of the patient population.

Patients and methods: The study included 98 patients who were diagnosed with prostate cancer. Age, percentages of positive cores (P+) at transrectal ultrasound scan biopsy, biopsy Gleason score (bGS), luteinizing hormone (LH), FSH, total testosterone, free testosterone (FT) and prostate-specific antigen (PSA) were the continuous clinical variables. All patients had not previously received hormonal manipulations. FSH correlation and multiple linear analyses were computed in the population. The FSH/PSA ratio was computed and then ranked for clustering the population as groups A (0.13≤FSH/PSA≤0.57), B (0.57<FSH/PSA≤1.61) and C (1.61<FSH/PSA≤19.4). The model was assessed by simple linear and multiple linear regression analysis and differences between the groups were assessed by analysis of variance.

Results: In the patient population, FSH correlated to LH (p < 0.0001), FT (p = 0.007) and age (p = 0.004). FSH was independently predicted by both LH (p < 0.0001) and PSA (p = 0.04). PSA predicted FSH/PSA A (p < 0.0001), B (p < 0.0001) and C (p = 0.04). On multiple regression analysis, FSH/PSA A was predicted by PSA (p < 0.0001), P+ (p = 0.03) and bGS (p = 0.04); FSH/PSA B by LH (p = 0.002) and PSA (p < 0.0001); FSH/PSA C by LH (p < 0.0001) and PSA (p < 0.0001). Moreover, FSH/PSA A, B and C differed for mean values of FSH (p < 0.0001), LH (p < 0.0001), PSA (p < 0.0001) and PSA/FT ratio (p < 0.0001). FSH/PSA clusters showed features of decreasing aggressive disease as the FSH/PSA ratio progressed from A to C.

Conclusion: At the diagnosis of prostate cancer and along the pituitary-testis-prostate axis in a patient population FSH significantly correlated to LH, FT and age, and FSH was independently and significantly predicted by both LH and PSA. Because of the independent prediction of PSA by FSH, the prostate cancer population at diagnosis was clustered and ranked according to the FSH/PSA ratio in groups A, B and C. Also, the predictive model of PSA on FSH for the different groups proved to be effective at selecting potential prognostic clusters in which the risk of progression might be assessed as low (group C), intermediate (group B) and high (group A). The FSH/PSA model might be considered as a tool for prostate cancer study and for use in individualized, risk-adapted approaches. However, confirmatory studies are needed.