Purpose: The Korean Cancer Study Group (KCSG) is a nationwide cancer clinical trial group dedicated to advancing investigator-initiated trials (IITs) by conducting and supporting clinical trials. This study aims to review IITs conducted by KCSG and quantitatively evaluate the survival and financial benefits of IITs for patients. Materials and Methods: We reviewed IITs conducted by KCSG from 1998 to 2023, analyzing progression-free survival (PFS) and overall survival (OS) gains for participants. PFS and OS benefits were calculated as the difference in median survival times between the intervention and control groups, multiplied by the number of patients in the intervention group. Financial benefits were assessed based on the cost of investigational products provided. Results: From 1998 to 2023, KCSG conducted 310 IITs, with 133 completed and published. Of these, 21 were included in the survival analysis. The analysis revealed that 1,951 patients in the intervention groups gained a total of 2,558.4 months (213.2 years) of PFS and 2,501.6 months (208.5 years) of OS, with median gains of 1.31 months in PFS and 1.58 months in OS per patient. When analyzing only statistically significant results, PFS and OS gain per patients was 1.69 months and 3.02 months, respectively. Investigational drug cost analysis from six available IITs indicated that investigational products provided to 252 patients were valued at 10,400,077,294 won (approximately 8,046,481 US dollars), averaging about 41,270,148 won (approximately 31,930 US dollars) per patient. Conclusion Our findings, based on analysis of published research, suggest that IITs conducted by KCSG led to survival benefits for participants and, in some studies, may have provided financial benefits by providing investment drugs.

Purpose: The Korean Cancer Study Group (KCSG) is a nationwide cancer clinical trial group dedicated to advancing investigator-initiated trials (IITs) by conducting and supporting clinical trials. This study aims to review IITs conducted by KCSG and quantitatively evaluate the survival and financial benefits of IITs for patients. Materials and Methods: We reviewed IITs conducted by KCSG from 1998 to 2023, analyzing progression-free survival (PFS) and overall survival (OS) gains for participants. PFS and OS benefits were calculated as the difference in median survival times between the intervention and control groups, multiplied by the number of patients in the intervention group. Financial benefits were assessed based on the cost of investigational products provided. Results: From 1998 to 2023, KCSG conducted 310 IITs, with 133 completed and published. Of these, 21 were included in the survival analysis. The analysis revealed that 1,951 patients in the intervention groups gained a total of 2,558.4 months (213.2 years) of PFS and 2,501.6 months (208.5 years) of OS, with median gains of 1.31 months in PFS and 1.58 months in OS per patient. When analyzing only statistically significant results, PFS and OS gain per patients was 1.69 months and 3.02 months, respectively. Investigational drug cost analysis from six available IITs indicated that investigational products provided to 252 patients were valued at 10,400,077,294 won (approximately 8,046,481 US dollars), averaging about 41,270,148 won (approximately 31,930 US dollars) per patient. Conclusion Our findings, based on analysis of published research, suggest that IITs conducted by KCSG led to survival benefits for participants and, in some studies, may have provided financial benefits by providing investment drugs.

Purpose: The Korean Cancer Study Group (KCSG) is a nationwide cancer clinical trial group dedicated to advancing investigator-initiated trials (IITs) by conducting and supporting clinical trials. This study aims to review IITs conducted by KCSG and quantitatively evaluate the survival and financial benefits of IITs for patients. Materials and Methods: We reviewed IITs conducted by KCSG from 1998 to 2023, analyzing progression-free survival (PFS) and overall survival (OS) gains for participants. PFS and OS benefits were calculated as the difference in median survival times between the intervention and control groups, multiplied by the number of patients in the intervention group. Financial benefits were assessed based on the cost of investigational products provided. Results: From 1998 to 2023, KCSG conducted 310 IITs, with 133 completed and published. Of these, 21 were included in the survival analysis. The analysis revealed that 1,951 patients in the intervention groups gained a total of 2,558.4 months (213.2 years) of PFS and 2,501.6 months (208.5 years) of OS, with median gains of 1.31 months in PFS and 1.58 months in OS per patient. When analyzing only statistically significant results, PFS and OS gain per patients was 1.69 months and 3.02 months, respectively. Investigational drug cost analysis from six available IITs indicated that investigational products provided to 252 patients were valued at 10,400,077,294 won (approximately 8,046,481 US dollars), averaging about 41,270,148 won (approximately 31,930 US dollars) per patient. Conclusion Our findings, based on analysis of published research, suggest that IITs conducted by KCSG led to survival benefits for participants and, in some studies, may have provided financial benefits by providing investment drugs.

Purpose: Individual anatomical structural variations, including intravesical prostatic protrusion (IPP), prostatic urethral angle (PUA), prostatic urethral length, or prostatic apex shape, were correlated with micturition symptoms. We aimed to investigate the effects of these variables on micturition symptoms in men with benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS). Methods: This observational study was based on data from 263 men with the first visit to health promotion center and without BPH/LUTS treatment between March 2020 and September 2022. A multivariate analysis was performed to determine the variables affecting total international prostate symptom score, maximum flow rate (Qmax), and voiding efficacy (postvoid residual volume to total bladder volume ratio). Results: Of 263 patients, decreasing PUA increases the severity of international prostate symptoms score (mild, 141.9°; moderate, 136.0°; severe, 131.2°; P<0.015). A multivariate analysis reported that the total international prostate symptom score was correlated with age (P=0.002), PUA (P=0.007), and Qmax (P=0.008). Qmax was negatively associated with IPP (P=0.002). In subanalysis for large prostate volume (≥30 mL, n=81), international prostate symptom score was correlated with PUA (P=0.013), Qmax was correlated with prostatic apex shape (P=0.017), and length of proximal prostatic urethra (P=0.007). IPP was not identified as a significant factor. For small prostate volume (<30 mL, n=182), age (P=0.011) and prostate volume (P=0.004) are correlated with increasing Qmax. Conclusions This study presented that individual anatomical structure variations influenced the micturition symptoms according to prostate volume. To identify the major resistant factors in men with BPH/LUTS, further studies are required to investigate which components played a role in major resistant factors for micturition symptoms.

Purpose: This study assessed the outcomes of microsurgical testicular sperm extraction (mTESE) and potential preoperative predictors of sperm retrieval (SR) in patients with non-obstructive azoospermia (NOA). Materials and Methods: Clinical data of 111 NOA patients who underwent mTESE was reviewed retrospectively. Baseline patient characteristics, including age, body mass index (BMI), testicular volumes, and preoperative endocrine levels, such as testosterone (T), follicle-stimulating hormone (FSH), serum-luteinizing hormone (LH), prolactin, sex hormone-binding globulin (SHBG), FSH/LH ratio along with T/LH ratio, were analyzed. After categorizing the patients into two groups based on SR success or failure, logistic regression analysis was performed to identify the preoperative predictors of successful SR. Results: Sixty-eight patients had successful SR (61.3%), whereas 43 patients (38.7%) showed negative results. Failed SR group had elevated serum FSH and LH levels, whereas successful SR patients had a significantly larger testicular volume (p<0.001). Moreover, the successful group had a higher T/LH ratio (p<0.001). Multivariate logistic analysis showed that the T/LH ratio, serum FSH levels, and bilateral testicular volumes were significantly associated with successful sperm extraction. Conclusion In addition to traditional predictors, such as testicular volume and preoperative FSH levels, the T/LH ratio is a potential independent predictor of successful SR in infertile patients with NOA.

Turtle leeches have not been recorded in Korea, although they occur in geographically adjacent countries including China and Japan. This study describes a turtle leech, Ozobranchus jantseanus (Clitellata: Ozobranchidae), found from Reeve’s turtle (Mauremys reevesii) in Korea. Of the 143 Reeve’s turtles collected from the freshwater reservoir in Jinju City, Gyeongsangnam-do, Korea, 95 unidentified leeches were found in 8 (5.6%) individuals. The leeches had 22 somites with 11 pairs of externally exposed branchiae, body-sized posterior suckers, and spines on the dorsal surface. We identified these leeches as Ozobranchus jantseanus Oka, 1912 (Clitellata: Ozobranchidae). This species of turtle leeches found in Korea may fill the gap in the biodiversity of East Asian annulus.

Purpose: The patient perception of study medication (PPSM) questionnaire consists of 12 questions designed to quantify patient satisfaction with the efficacy of study treatment by focusing on specific changes that patients experience during the study period. This study aimed to develop a Korean version of the PPSM questionnaire. Methods: The linguistic validation process consisted of obtaining permission for translation, forward translation, reconciliation, backward translation, cognitive debriefing, and proofreading. Two independent bilingual translators translated the original version of the questionnaire, and a panel discussed and combined the 2 versions. Another independent translator performed backward translation of the reconciled version, after which 15 patients underwent the cognitive debriefing. Results: The 12 questions and 4 response scales of the PPSM questionnaire were forward translated into 2 Korean versions. The terms were adjusted to conceptually equivalent expressions in Korean. After backward translation, the panel made minor changes to the forward translations for brevity and better readability. No difficulties were experienced during cognitive debriefing by 15 patients, and all items were reported to be generally easy to understand. Conclusions The Korean version of the PPSM questionnaire has been successfully translated and validated. The questionnaire is appropriate for assessing symptom satisfaction in patients that undergo benign prostatic hyperplasia pharmacotherapy.

Purpose: We investigated the role of prostate-specific antigen (PSA) variation as a predictor of prostate cancer in patients who underwent prebiopsy multiparametric magnetic resonance imaging (MRI). Materials and Methods: The clinicopathological data of 266 patients with PSA ≤20 ng/mL who underwent prebiopsy MRI and prostate biopsy between September 2019 and February 2021 were included. PSA variation was defined as the difference in PSA values taken when a prostate biopsy was recommended and performed (median 20 days). Receiver operating characteristic (ROC) curves and area under the ROC curves (AUCs) for predicting prostate cancer were analyzed through 4 models that considered conventional clinical variables and PSA variation. Results: Of the 258 patients, 166 (64.3%) were diagnosed with prostate cancer. The prostate cancer (+) group had a lower median PSA variation (-0.09 mg/mL vs. -0.27 ng/mL, p=0.006) and higher proportion of patients with PSA variation within -0.54 to 0.05 ng/mL (40 ng/mL [range, 24.1%] vs. 9 ng/mL [9.8%], p=0.002) than the prostate cancer (-) group. There was no significant difference in the duration between the 2 PSA measurements. When PSA variation and conventional variables, such as age, PSA density, prostate biopsy history, number of target lesions, were considered, the highest AUC value was 0.870. In a subgroup analysis of patients with PSA ≤10 ng/mL, the highest AUC value was 0.860 when PSA variation and conventional variables were considered. Conclusions A large PSA variation within 1 month was a negative predictor of prostate cancer among patients who underwent prebiopsy MRI.

Decision-making for treatment of newly diagnosed prostate cancer (PCa) is complex due to the multiple initial treatment modalities available. We aimed to externally validate the SCaP (Severance Study Group of Prostate Cancer) Survival Calculator that incorporates a long short-term memory artificial neural network (ANN) model to estimate survival outcomes of PCa according to initial treatment modality. Materials and Methods The validation cohort consisted of clinicopathological data of 4,415 patients diagnosed with biopsy-proven PCa between April 2005 and November 2018 at three institutions. Area under the curves (AUCs) and time-to-event calibration plots were utilized to determine the predictive accuracies of the SCaP Survival Calculator in terms of progression to castration-resistant PCa (CRPC)–free survival, cancer-specific survival (CSS), and overall survival (OS). Results Excellent discrimination was observed for CRPC-free survival, CSS, and OS outcomes, with AUCs of 0.962, 0.944, and 0.884 for 5-year outcomes and 0.959, 0.928, and 0.854 for 10-year outcomes, respectively. The AUC values were higher for all survival endpoints compared to those of the development cohort. Calibration plots showed that predicted probabilities of 5-year survival endpoints had concordance comparable to those of the observed frequencies. However, calibration performances declined for 10-year predictions with an overall underestimation. Conclusion The SCaP Survival Calculator is a reliable and useful tool for determining the optimal initial treatment modality and for guiding survival predictions for patients with newly diagnosed PCa. Further modifications in the ANN model incorporating cases with more extended follow-up periods are warranted to improve the ANN model for long-term predictions.

Purpose: To identify the indication for recommending prebiopsy magnetic resonance imaging (MRI) to prevent prostate cancer missed diagnoses in cases without prebiopsy MRI. Materials and Methods: Between January 2017 and September 2020, 585 patients suspected with prostate cancer underwent prostate biopsy after MRI. For patients with visible lesions, MRI-targeted biopsy using an image-based fusion program was performed in addition to the 12- core systematic biopsy. Patients for whom MRI was performed in other institutions (n=4) and patients who underwent target biopsy alone (n=7) were excluded. Results: Of 574 patients (median prostate-specific antigen [PSA] level, 6.88 ng/mL; mean age, 68.2 years), 342 (59.6%) were diagnosed with prostate cancer (visible lesions=312/449 [69.5%]; nonvisible lesions=30/123 [24.0%]). The detection rates of visible lesions stratified using the Prostate Imaging Reporting and Data System score (3 vs. 4 vs. 5) were 30.9% (54 of 175), 61.2% (150 of 245), and 90.1% (127 of 141), respectively. Multivariate analysis showed that PSA density was a significant factor for presence of visible lesions, prostate cancer, and significant prostate cancer diagnosis. Among patients with positive lesions, 27 (8.2%) were diagnosed with prostate cancer concomitant with negative systematic biopsy results. A PSA density of 0.15 ng/mL/cm3 was identified as the significant cutoff value for predicting positive target biopsy in groups with negative systematic biopsy. Sixty of the negative target lesions (26.1%) were diagnosed using systematic biopsy. Conclusions To maximize cancer detection rates, both targeted and systematic biopsies should be implemented. PSA density was identified as a useful factor for recommending prebiopsy MRI to patients suspected with prostate cancer.