Patient's Factors Correlated with Prostate Volume Recovery after 5 Alpha Reductase Inhibitor Discontinuation

Purpose The 5 alpha reductase inhibitor (5ARI) reduces the size of the prostate and alleviates lower urinary tract symptoms. After stopping 5ARI, the prostate quickly recovers to its pre-medication size. The purpose of this study was to investigate the factors affecting the restoration of prostate size after 5ARI discontinuation. Materials and Methods Between March 2009 and May 2017, patients who visited an outpatient clinic and were diagnosed with benign prostatic hyperplasia were selected and start 5ARI medication. After 6 months of medication, the patients stopped medication for 1 year. Meanwhile, we measured the prostate volumes of patients 3 times (before and after medication, after discontinuation) and divide the patients into 3 groups (maintained, intermediate, and restored) with recovered prostate volume ratio. After classification, we investigated the relationship between the variable factors (age, serum prostate-specific antigen, initial volume, reduced volume after medication) between groups. Results Among the 147 selected patients, the mean age and plasma PSA level were 61.6±7.9 and 0.8±0.6, respectively. The mean initial prostate volume was 32.3±4.2 ml, which reduced to 23.2±3.2 ml after medication. After one year of discontinuation, the mean volume was 31.4±6.4 ml, with restoration to 101.5% of the reduced size. We noticed a tendency that patients with faster prostate volume recovery were generally older than those with slower recovery; however, this was not statistically significant. Other factors showed no relationship with prostate recovery. Conclusions When using 5ARI in elderly patients, continuous treatment seems better than intermittent treatment. If discontinuation is needed, short term follow-up is recommended.