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: Vascular endothelial growth factor tyrosine kinase inhibitors (TKIs) have been the standard of care for advanced and metastatic clear cell renal cell carcinoma (ccRCC). However, the therapeutic effect of TKI monotherapy remains unsatisfactory given the high rates of acquired resistance to TKI therapy despite favorable initial tumor response. Materials and Methods: To define the TKI-resistance mechanism and identify new therapeutic target for TKI-resistant ccRCC, an integrative differential gene expression analysis was performed using acquired resistant cohort and a public dataset. Sunitinib-resistant RCC cell lines were established and used to test their malignant behaviors of TKI resistance through in vitro and in vivo studies. Immunohistochemistry was conducted to compare expression between the tumor and normal kidney and verify expression of pathway-related proteins. Results: Integrated differential gene expression analysis revealed increased interferon-induced transmembrane protein 3 (IFITM3) expression in post-TKI samples. IFITM3 expression was increased in ccRCC compared with the normal kidney. TKI-resistant RCC cells showed high expression of IFITM3 compared with TKI-sensitive cells and displayed aggressive biologic features such as higher proliferative ability, clonogenic survival, migration, and invasion while being treated with sunitinib. These aggressive features were suppressed by the inhibition of IFITM3 expression and promoted by IFITM3 overexpression, and these findings were confirmed in a xenograft model. IFITM3-mediated TKI resistance was associated with the activation of TRAF6 and MAPK/AP-1 pathways. Conclusions These results demonstrate IFITM3-mediated activation of the TRAF6/MAPK/AP-1 pathways as a mechanism of acquired TKI resistance, and suggest IFITM3 as a new target for TKI-resistant ccRCC.

Purpose: Adrenocortical carcinoma (ACC) is a rare primary carcinoma originating in the adrenal gland with a poor prognosis and a high recurrence rate. This study evaluated the risk factors associated with recurrence in patients with early stage ACC after curative surgical resection. Methods: The present study retrospectively evaluated the risk factors for recurrence in 38 patients with stages 1 and 2 ACC who underwent curative resection between 1995 and 2020. Results: Recurrence was observed in 21 patients (55.3%), with no significant difference between stages 1 and 2 ACC (P = 0.640). The overall recurrence rate was higher in patients who underwent minimally invasive surgery than open adrenalectomy (71.4% vs. 51.6%). Of the 33 patients with gross tumor margins negative for malignancy, 16 (48.5%) experienced tumor recurrence, and all 5 patients with positive and unknown gross resection margins had recurrence.Recurrences were observed in 14 of the 30 patients (46.7%) negative for pathologic resection margins, 6 of the 7 patients (85.7%) with pathologically indeterminate margins, and 1 patient with pathologically positive margins. Conclusion The recurrence rates are high even in patients with early stage ACC, being higher in patients who undergo minimally invasive surgery than open adrenalectomy. Obtaining clear resection margins during surgery may reduce tumor recurrence; however, gross or pathologic margin safety was not a secure factor in preventing recurrence. None of the factors analyzed was a definitive predictor of poor prognosis.

Purpose: Small cell carcinoma of the genitourinary tract (GU SCC) is a rare disease with a poor prognosis. There are only limited treatment options due to insufficient understanding of the disease. In this study, we analyzed the clinical outcomes of patients with GU SCC and their association with the tumor immune phenotype. Materials and Methods: Patients diagnosed with GU SCC were included. Survival outcomes according to the primary location (prostate and non-prostate) and stages (limited disease [LD] and extensive disease [ED]) were analyzed. We performed multiplex immunohistochemistry (IHC) in non-prostate SCC patients and analyzed the immune cell population. Results: A total of 77 patients were included in this study. Their median age was 71 years, 67 patients (87.0%) were male, and 48 patients (62.3%) had non-prostate SCC. All patients with ED (n=31, 40.3%) received etoposide plus platinum (EP) as initial treatment and median overall survival (OS) was 9.7 months (95% confidence interval [CI], 7.1 to 18.6). Patients with LD (n=46, 59.7%) received EP followed by radiotherapy or surgery, and 24-months OS rate was 63.6% (95% CI, 49.9 to 81.0). The multiplex IHC analysis of 21 patients with non-prostate SCC showed that patients with a higher density of programmed death-ligand 1–expressing CD68+CD206+ M2-like macrophages had significantly worse OS outcomes with an adjusted hazards ratio of 4.17 (95% CI, 1.25 to 14.29; adjusted p=0.02). Conclusion Patients with GU SCC had a poor prognosis, even those with localized disease. The tumor immune phenotypes were significantly associated with survival. This finding provides new insights for treating GU SCC.

Purpose: Evidence in favor of adding docetaxel in treatment of metastatic hormone-sensitive prostate cancer (mHSPC) has led to docetaxel in conjunction with androgen deprivation therapy (ADT) as standard therapy. The aim of this study was to examine the effectiveness of docetaxel with ADT for Korean patients with mHSPC in real-world practice. Materials and Methods: A retrospective cohort study was performed at six Korean hospitals for patients with mHSPC treated with docetaxel plus ADT. Patients were treated every 3 weeks for up to six cycles with 75 mg/m 2 of docetaxel. The primary endpoint was time to castration resistant prostate cancer (CRPC). Results: This study included 46 eligible patients from June 2016 to February 2021. Median age was 68.5 years (range, 52–84) and all patients present with de novo M1 with high-volume disease. The median prostate-specific antigen (PSA) level at ADT initiation was 205.4 (7.7–1933) ng/mL, and time from ADT to docetaxel was 2.4 months (0–5.3). All six planned cycles of docetaxel were delivered in 36 patients (78%), 7 patients (15%) discontinued treatment due to adverse events, and 3 patients (7%) discontinued due to progression. At the time of the analysis, CRPC had developed in 34 patients (74%), and the median time to CRPC was 18.0 (95% confidence interval, 14.1–21.9) months. PSA <0.2 ng/mL was achieved in 11 patients (24%) after 6 months of ADT and in 10 patients (22%) after 12 months. At last follow-up, 35 patients (76%) were alive; the median overall survival was not reached. Conclusion The effect of docetaxel combined with ADT for Korean patients with mHSPC is comparable with prior results in Western studies.

Purpose: Tyrosine kinase inhibitors (TKI) targeting vascular endothelial growth factor receptor (VEGFR) signaling pathways have been used for metastatic clear cell renal cell carcinoma (mCCRCC), but resistance to the drug develops in most patients. We aimed to explore the underlying mechanism of the TKI resistance with regard to programmed death-ligand 1 (PD-L1) and to investigate signaling pathway associated with the resistant mechanism. Materials and Methods: To determine the mechanism of resistance, 10 mCCRCC patients from whom tumor tissues were harvested at both the pretreatment and the TKI-resistant post-treatment period were included as the discovery cohort, and their global gene expression profiles were compared. A TKI-resistant renal cancer cell line was established by long-term treatment with sunitinib. Results: Among differentially expressed genes in the discovery cohort, increased PD-L1 expression in post-treatment tissues was noted in four patients. Pathway analysis showed that PD-L1 expression was positively correlated with the mammalian target of rapamycin (mTOR) signaling pathway. The TKI-resistant renal cancer cells showed increased expression of PD-L1 and mTOR signaling proteins and demonstrated aggressive tumoral behaviour. Treatment with mTOR inhibitors down-regulated PD-L1 expression and suppressed aggressive tumoral behaviour, which was reversed with stimulation of the mTOR pathway. Conclusion These results showed that PD-L1 expression may be increased in a subset of VEGFR-TKI–resistant mCCRCC patients via the mTOR pathway.

Purpose: This post-marketing surveillance (PMS) study was conducted to monitor the usage of axitinib (Inlyta) in clinical practice of Korean patients with advanced renal cell carcinoma (RCC) with disease progression during or after a prior systemic therapy in real world. Materials and Methods: In this multicenter, observational study, patients indicated for oral axitinib 5 mg twice daily as second-line therapy for advanced RCC were followed up under routine clinical practices, and their safety and effectiveness outcomes were collected. Results: Between 2012 and 2021, 125 patients were enrolled, and data from 111 patients were analyzed. Median age was 65 years (range, 30 to 84 years), 81% was male, and 110 (99%) had clear cell RCC. The median daily dose of axitinib was 10 mg (range, 4.36 to 15.95 mg) with a median administration period of 5.6 months (range, 15 to 750 days). Eighty-three percentage of patients experienced any grade of adverse events, 71% of which were related to study treatment, including diarrhea (36%), hypertension (21%), stomatitis (17%), decreased appetite (14%), palmar-plantar erythrodysesthesia syndrome (12%), and asthenia (11%). Most adverse events were generally well tolerated and manageable, with 13% of grade ≥ 3. Axitinib dose reduction was required in 20% of the adverse events and discontinuation in 8%. Median progression-free survival was 12.4 months (95% confidence interval [CI], 9.6 to 18.9). Objective responses were observed in 30% of patients (95% CI, 21 to 39) with 4% of complete response and 26% of partial response. Conclusion No new safety signal was found in the present PMS study of Korean RCC patients. Axitinib showed consistent outcomes in terms of effectiveness and safety confirming that the drug is a valid option for second-line therapy in patients with advanced RCC in a real-world setting.

Purpose: This study aims to evaluate the prognosis of pathologically node-positive bladder cancer after neoadjuvant chemotherapy, the role of adjuvant chemotherapy in these patients, and the value of preoperative clinical evaluation for lymph node metastases. Materials and Methods: Patients who received neoadjuvant chemotherapy followed by partial/radical cystectomy and had pathologically confirmed lymph node metastases between January 2007 and December 2019 were identified and analyzed. Results: A total of 53 patients were included in the study. The median age was 61 years (range, 34 to 81 years) with males comprising 86.8%. Among the 52 patients with post-neoadjuvant/pre-operative computed tomography results, only 33 patients (63.5%) were considered positive for lymph node metastasis. Sixteen patients (30.2%) received adjuvant chemotherapy (AC group), and 37 patients did not (no AC group). With the median follow-up duration of 67.7 months, the median recurrence-free survival (RFS) and the median overall survival (OS) was 8.5 months and 16.2 months, respectively. The 2-year RFS and OS rates were 23.3% and 34.6%, respectively. RFS and OS did not differ between the AC group and no AC group (median RFS, 8.8 months vs. 6.8 months, p=0.772; median OS, 16.1 months vs. 16.3 months, p=0.479). Thirty-eight patients (71.7%) experienced recurrence. Distant metastases were the dominant pattern of failure in both the AC group (91.7%) and no AC group (76.9%). Conclusion Patients with lymph node-positive disease after neoadjuvant chemotherapy followed by surgery showed high recurrence rates with limited survival outcomes. Little benefit was observed with the addition of adjuvant chemotherapy.