Does intensity-modulated radiation therapy by helical tomotherapy for prostate cancer increase the subsequent risk of bladder cancer? A propensity score-matched analysis.

OBJECTIVES: This study aimed to evaluate the risk of bladder cancer after intensity-modulated radiation therapy (IMRT) using helical tomotherapy for prostate cancer in comparison to the risk post-radical prostatectomy (RP) using propensity score-matched analysis and to assess the risk factors for bladder cancer. METHODS: This retrospective study included 2067 patients with non-metastatic prostate cancer treated at our institution between June 2007 and December 2016. Of these, 1547 patients were treated with IMRT and 520 underwent RP. The propensity scores were calculated using age, National Comprehensive Cancer Network risk classification, prostate volume, Brinkman index, and follow-up time as matched covariates. A propensity score-matched patient cohort (n = 718; IMRT: 359, RP: 359) was created, and the risk of bladder cancer after treatment was compared. RESULTS: In total, bladder cancer was detected in 33 patients. Five patients in the IMRT group and one in the RP group died of bladder cancer. In the propensity score-matched analysis, the 5-year bladder cancer-free survival rate was significantly lower in the IMRT group than in the RP group (91.7% and 96.2%, respectively; p < 0.001). Multivariate analysis revealed that IMRT and the Brinkman index were the risk factors for bladder cancer in this cohort (odds ratio = 5.085, 95% confidence interval = 1.436-18.008, p = 0.012 and odds ratio = 1.001, 95% confidence interval = 1.000-1.001, p = 0.010, respectively). CONCLUSIONS: IMRT for prostate cancer using helical tomotherapy increases the subsequent risk of bladder cancer compared with RP and is an independent risk factor for bladder cancer similar to smoking.

Three-dimensional ultrasonography in evaluation of benign prostatic hyperplasia.

BACKGROUND: The clinical application of volume estimation by 3-D ultrasound has recently gained much attention. However, there have been no reports evaluating the prostate volume by 3-D transrectal ultrasound (TRUS) before transurethral resection of the prostate (TURP). The purpose of the present study was to evaluate the value of 3-D TRUS for prediction of prostate morphology and resected weight before TURP and to investigate whether 3-D TRUS is a more useful examination than 2D TRUS in patients with benign prostatic hyperplasia (BPH). METHODS: Transurethral resection of the prostate was performed in 23 patients with BPH. We evaluated the prostate morphology and measured both the volumes of the whole prostate and the transition zone using 2-D and 3-D TRUS, respectively. The actual resected weight was recorded and compared with the volume of the whole prostate and that of the transition zone measured by 2D and 3-D TRUS. RESULTS: The volume of the transition zone measured by 3-D TRUS correlated most strongly with the resected weight (r = 0.84). A large median lobe was seen in three patients in whom the transition zone volume measured by 2-D TRUS was considerably larger than the resected weight. However, overestimation in the three patients decreased by the use of 3-D TRUS. CONCLUSIONS: It was concluded that 3-D TRUS was equal or superior to 2-D TRUS in prediction of the resected weight and 3-D TRUS offers better information as a diagnostic tool before TURP.