• Radiation Oncology Journal
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• v.38 no.1
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• pp.52-59
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• 2020

Purpose: To evaluate and compare the feasibilities of magnetic resonance (MR) image-based planning using synthetic computed tomography (sCT) versus CT (pCT)-based planning in helical tomotherapy for prostate cancer. Materials and Methods: A retrospective evaluation was performed in 16 patients with prostate cancer who had been treated with helical tomotherapy. MR images were acquired using a dedicated therapy sequence; sCT images were generated using magnetic resonance for calculating attenuation (MRCAT). The three-dimensional dose distribution according to sCT was recalculated using a previously optimized plan and was compared with the doses calculated using pCT. Results: The mean planning target volume doses calculated by sCT and pCT differed by 0.65% ± 1.11% (p = 0.03). Three-dimensional gamma analysis at a 2%/2 mm dose difference/distance to agreement yielded a pass rate of 0.976 (range, 0.658 to 0.986). Conclusion: The dose distribution results obtained using tomotherapy from MR-only simulations were in good agreement with the dose distribution results from simulation CT, with mean dose differences of less than 1% for target volume and normal organs in patients with prostate cancer.

• Radiation Oncology Journal
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• v.38 no.1
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• pp.60-67
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• 2020

Purpose: We performed three-dimensional (3D) dose reconstruction-based pretreatment verification to evaluate gamma analysis acceptance criteria in volumetric modulated arc therapy (VMAT) for prostate cancer. Materials and Methods: Pretreatment verification for 28 VMAT plans for prostate cancer was performed using the COMPASS system with a dolphin detector. The 3D reconstructed dose distribution of the treatment planning system calculation (TC) was compared with that of COMPASS independent calculation (CC) and COMPASS reconstruction from the dolphin detector measurement (CR). Gamma results (gamma failure rate and average gamma value [GFR and γAvg]) and dose-volume histogram (DVH) deviations, 98%, 2% and mean dose-volume difference (DD_98%, DD_2% and DD_mean), were evaluated. Gamma analyses were performed with two acceptance criteria, 2%/2 mm and 3%/3 mm. Results: The GFR in 2%/2 mm criteria were less than 8%, and those in 3%/3 mm criteria were less than 1% for all structures in comparisons between TC, CC, and CR. In the comparison between TC and CR, GFR and γAvg in 2%/2 mm criteria were significantly higher than those in 3%/3 mm criteria. The DVH deviations were within 2%, except for DD_mean (%) for rectum and bladder. Conclusions: The 3%/3 mm criteria were not strict enough to identify any discrepancies between planned and measured doses, and DVH deviations were less than 2% in most parameters. Therefore, gamma criteria of 2%/2 mm and DVH related parameters could be a useful tool for pretreatment verification for VMAT in prostate cancer.

• Journal of Yeungnam Medical Science
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• v.40 no.4
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• pp.412-418
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• 2023

Background: The aim of this study was to evaluate the risk factors for prostate-specific antigen (PSA) persistence in pathological stage T3aN0 prostate cancer (PCa) after robot-assisted laparoscopic radical prostatectomy (RALP). Methods: A retrospective study was performed on 326 patients with pT3aN0 PCa who underwent RALP between March 2020 and February 2022. PSA persistence was defined as nadir PSA of >0.1 ng/mL after RALP, and the risk factors for PSA persistence were evaluated using logistic regression analysis. Results: Among 326 patients, 61 (18.71%) had PSA persistence and 265 (81.29%) had PSA of <0.1 ng/mL after RALP (successful radical prostatectomy [RP] group). In the PSA persistence group, 51 patients (83.61%) received adjuvant treatment. Biochemical recurrence occurred in 27 patients (10.19%) in the successful RP group during the mean follow-up period of 15.22 months. Multivariate analysis showed that the risk factors for PSA persistence were large prostate volume (hazard ratio [HR], 1.017; 95% confidence interval [CI], 1.002-1.036; p=0.046), lymphovascular invasion (LVI) (HR, 2.605; 95% CI, 1.022-6.643; p=0.045), and surgical margin involvement (HR, 2.220; 95% CI, 1.110-4.438; p=0.024). Conclusion: Adjuvant treatment may be needed for improved prognosis in patients with pT3aN0 PCa after RALP with a large prostate size, LVI, or surgical margin involvement.

• The Korean Journal of Urological Oncology
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• 제15권3호
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• pp.131-136
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• 2017

Purpose: The aim of this study is to investigate the criteria of biochemical recurrence (BCR) and follow-up periods and methods with and without blood and imaging test of urologic oncology before established guidelines of prostate cancer in Korea. Materials and Methods: In December 2015, we sent the questionnaire to urologic oncologist in academic hospital and received the answer from 108 urologic oncologist (50%). Also, we analyzed the data of 1,141 patients underwent radical prostatectomy in 2005 from Korean Medical Insurance. Results: In follow-up, 72 physicians (66.7%) performed blood test every 3 months, 51 physicians (47.2%) performed imaging study in case of BCR. Bone scan was the most common imaging study in the follow-up (74 physicians, 68.5%). But, bone scan was only performed in case of BCR (43 physicians, 39.8%). The criteria of BCR was PSA 0.2 ng/mL (75 physician, 69.4%), 76 physicians (70.4%) was performed different follow-up according to risk of patients. In Korean Medical Insurance data analysis, PSA were performed average 2 times every year and magnetic resonance imaging, computed tomography, Bone scan were performed average 0.1, 0.2, 0.1 times every year, respectively. Conclusions: The criteria of BCR and the follow-up of prostate cancer patients in Korea were similar Korean prostate cancer guidelines. Blood and imaging test might be increased compared to 10 years ago, it is necessary to compare the Korean Medical Insurance data between 10 years ago and present.

• Investigative and Clinical Urology
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• v.59 no.6
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• pp.363-370
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• 2018

Purpose: The aim of this study is to describe the technique and to report early results of transperineal magnetic resonance imaging and ultrasonography (MRI-US) fusion biopsy. Materials and Methods: A total of 75 patients underwent MRI-US fusion transperineal biopsy. Targeted biopsy via MRI-US fusion imaging was carried out for cancer-suspicious lesions with additional systematic biopsy. Detection rates for overall and clinically significant prostate cancer (csPCa) were evaluated and compared between systematic and targeted biopsy. In addition, further investigation into the detection rate according to prostate imaging reporting and data system (PI-RADS) score was done. Results of repeat biopsies were also evaluated. Results: Overall cancer detection rate was 61.3% (46 patients) and the detection rate for csPCa was 42.7% (32 patients). Overall detection rates for systematic and targeted biopsy were 41.3% and 57.3% (p<0.05), respectively. Detection rates for csPCa were 26.7% and 41.3%, respectively (p<0.05). The cancer detection rates via MRI fusion target biopsy were 30.8% in PI-RADS 3, 62.1% in PI-RADS 4 and 89.4% in PI-RADS 5. Rates of csPCa missed by targeted biopsy and systematic biopsy were 0.0% and 25.0%, respectively. The cancer detection rate in repeat biopsies was 61.1% (11 among 18 patients) in which 55.5% of cancer suspected lesions were located in the anterior portion. Conclusions: Transperineal MRI-US fusion biopsy is useful for improving overall cancer detection rate and especially detection of csPCa. Transperineal MRI-US targeted biopsy show potential benefits to improve cancer detection rate in patients with high PIRADS score, tumor located at the anterior portion and in repeat biopsies.