Magnetic resonance spectroscopy in patients with locally confined prostate cancer: association of prostatic citrate and metabolic atrophy with time on hormone deprivation therapy, PSA level, and biopsy Gleason score.

This study was undertaken to determine respective associations between prostatic citrate or metabolic atrophy (no detectable citrate, choline, and creatine) at magnetic resonance spectroscopy (MRS) and time on hormone-deprivation therapy, serum PSA, and biopsy Gleason score. Clinical data, histopathology reports and PSA levels of 36 patients on hormone-deprivation therapy (age, 64+/-9 years, pre-therapeutic biopsy Gleason sum, median 6, range 3-8, antiandrogens only, n=3, LHRH-analogues only, n=4, combined hormone-deprivation therapy, n=29, duration, 27+/-19 weeks) for locally confined prostate cancer (PCA) were retrospectively correlated with findings in the peripheral zone of the prostate at 3D-MRS (endorectal coil, PRESS, TR 1,000 ms, TE 130 ms). The results show that citrate was usually detected after 13 weeks or less of hormone-deprivation therapy (10/12 vs. 6/24 patients, chi-square-test, p=0.002). All patients with PSA levels exceeding 0.20 ng/ml had detectable metabolites (citrate, n=12, choline without citrate, n=6), while 9/18 patients with PSA 0.20 ng/ml or less showed metabolic atrophy (Fisher-exact-test, p=0.001). There were no significant associations between citrate, metabolic atrophy, pre-therapeutic PSA, and biopsy Gleason sum, respectively. It has been concluded that hormone-deprivation therapy for locally confined PCA has not reached its full deprivation potential after 13 weeks. MRS detects prostate metabolism in patients with PSA exceeding 0.20 ng/ml after hormone-deprivation therapy.