The efficacy of second-line tyrosine kinase inhibitor for patients with metastatic non-clear cell renal cell carcinoma following first-line immune-oncology combination therapy.

PURPOSE: Metastatic non-clear cell renal cell carcinoma (nccRCC) is a heterogeneous disease with a poor prognosis and is treated with immunotherapy (IO)-based combinations according to the clear cell renal cell carcinoma. Tyrosine-kinase inhibitors (TKIs), such as cabozantinib and axitinib, are commonly used as the 2nd line therapy after 1st line IO combination therapy, but their efficacy as 2nd line TKI therapy for nccRCC is unknown. In this study, we performed a retrospective multicenter analysis of nccRCC patients who were previously treated with IO combination therapy and received 2nd line TKIs. METHODS: Among 254 patients enrolled in the Japanese multicenter retrospective study, 52 patients with nccRCC histology who received second-line TKIs were included in this study. Progression-free survival and overall survival (OS) from 2nd line TKIs were analyzed by log-rank test and Cox-proportional hazard model. Objective response rate (ORR) of 2nd line TKIs were analyzed. RESULTS: The 1-year PFS and OS rates were 25.0% (95% CI = 13.1-36.8) and 63.8% (95% CI, 48.0-75.9), respectively. No patients had a complete response, 11 had a partial response, and 18 had stable disease. ORR was 21.1%. IMDC poor risk and sunitinib as the 2nd line therapy were significantly associated with poor PFS. CONCLUSION: The 2nd-line TKI was effective for a small group of nccRCC patients previously treated with IO combination therapy, although this study was retrospectively analyzed with a small number of cases.

Impact of prostate position-based image-guidance in intensity-modulated radiation therapy for localized prostate cancer.

BACKGROUND/PURPOSE: The long-term clinical impact of prostate position-based image-guided radiotherapy (IGRT) for localized prostate cancer remains unclear. MATERIALS AND METHODS: We retrospectively compared clinical outcomes following intensity-modulated radiation therapy (IMRT) with cone-beam computed tomography-based prostate position-based IGRT (P-IGRT) or without P-IGRT (non-P-IGRT). From June 2011, we applied P-IGRT in IMRT for intermediate-risk (IR) prostate cancer (PCa) (D'Amico risk classification) (76 Gy in 38 fractions, with smaller margins). Clinical outcomes of patients who received P-IGRT between June 2011 and June 2019 were retrospectively compared with those of patients with IR PCa who received IMRT without P-IGRT between October 2002 and May 2011 in our institution (74 Gy in 37 fractions). RESULTS: A total of 222 consecutive patients were analyzed: 114 in the P-IGRT cohort and 108 in the non-P-IGRT cohort. The median follow-up period after IMRT was 7.1 years for the P-IGRT cohort and 10.8 years for the non-P-IGRT cohort. The biochemical failure-free rate was significantly better in the P-IGRT cohort (94.9% for the P-IGRT cohort vs 82.7% for the non-P-IGRT cohort at 10 years, p = 0.041). The rate of rectal bleeding which needs intervention including the use of suppositories was significantly lower in the P-IGRT cohort (p < 0.001). CONCLUSIONS: The use of P-IGRT with higher doses and smaller margins was correlated with significantly better biochemical control, and a lower incidence of rectal bleeding in IMRT for intermediate-risk prostate cancer. The enhanced accuracy using P-IGRT has the potential to independently improve disease control and reduce late rectal bleeding.

Clinical factors predicting the outcome of salvage radiotherapy for patients with biochemical recurrence after radical prostatectomy.

BACKGROUND: It remains unclear which patients with biochemical recurrence after prostatectomy are most suitable for salvage radiotherapy. We evaluated the parameters related to outcomes. METHODS: We retrospectively evaluated patients who underwent salvage therapy for biochemical recurrence after prostatectomy between 2005 and 2019. This study aimed to evaluate biochemical recurrence-free survival (bRFS) after salvage radiotherapy and elucidate the parameters associated with bRFS. The bRFS rate was calculated using the Kaplan-Meier method, and the parameters associated with bRFS were evaluated using Cox regression analysis. RESULTS: This study included 67 patients treated with salvage radiotherapy with a median age of 67 years at salvage radiotherapy. The median follow-up period after salvage radiotherapy was 7.3 years. The 5-year bRFS rate following salvage radiotherapy was 47.1%. Univariate analysis showed that PSA doubling time < 6 months, positive surgical margin, and pathological Gleason score ≥ 8 were significantly associated with shorter bRFS (p < 0.001, p = 0.036, p = 0.047, respectively). Multivariable analysis showed that a PSA doubling time < 6 months and positive surgical margins were significantly associated with shorter bRFS (p = 0.001 and p = 0.018, respectively). No serious adverse events were observed. CONCLUSIONS: In our hospital, approximately half of the patients are under long-term control with salvage radiotherapy. A PSA doubling time of < 6 months and positive surgical margins were suggested to be associated with poor outcomes of salvage radiotherapy.

Current trends in the promising immune checkpoint inhibition and radiotherapy combination for locally advanced and metastatic urothelial carcinoma.

Locally advanced and metastatic urothelial carcinoma (UC) remains a challenging malignancy, though several novel therapeutic drugs have been developed in recent years. Over the past decade, immune checkpoint inhibitors (ICI) have shifted the paradigm of therapeutic strategies for UC; however, only a limited number of patients respond to ICI. Since radiotherapy (RT) is widely known to induce systemic immune activation, it may boost the efficacy of ICI. Conversely, RT also causes exhaustion of cytotoxic T cells, and the activation and recruitment of immunosuppressive cells; ICI may help overcome these immunosuppressive effects. Therefore, the combination of ICI and RT has attracted attention in recent years. The therapeutic benefits of this combination therapy and its optimal regimen have not yet been determined through prospective studies. Therefore, this review article aimed to provide an overview of the current preclinical and clinical studies that illustrate the underlying mechanisms and explore the optimization of the RT regimen along with the ICI and RT combination sequence. We also analyzed ongoing prospective studies on ICI and RT combination therapies for metastatic UC. We noted that the tumor response to ICI and RT combination seemingly differs among cancer types. Thus, our findings highlight the need for well-designed prospective trials to determine the optimal combination of ICI and RT for locally advanced and metastatic UC.

Pre-pembrolizumab neutrophil-to-lymphocyte ratio (NLR) predicts the efficacy of second-line pembrolizumab treatment in urothelial cancer regardless of the pre-chemo NLR.

Neutrophil-to-lymphocyte ratio (NLR) was reported to be associated with prognosis of urothelial cancer (UC) patients receiving systemic chemotherapy or immunotherapy. However, it has not been elucidated how preceding first-line chemotherapy affects NLR and subsequent second-line pembrolizumab treatment. This multicenter study analyzed 458 patients with metastatic UC who received first-line chemotherapy and second-line pembrolizumab with regard to pre-chemotherapy and pre-pembrolizumab NLR in association with the efficacy of chemotherapy and pembrolizumab treatment. NLR was increased in 47% while decreased in 53% of patients before and after first-line chemotherapy. High pre-chemotherapy NLR (≥ 3) was significantly associated with unfavorable overall (OS, P = 0.0001) and progression-free (P < 0.0001) survivals after first-line chemotherapy. However, pre-chemotherapy NLR showed only modest influence on radiological response and survival after second-line pembrolizumab treatment, whereas pre-pembrolizumab NLR showed higher association. NLR decrease was associated with partial response or greater objective response by first-line chemotherapy, while NLR increase was associated with higher patient age. In conclusion, immediate pre-chemotherapy and pre-pembrolizumab NLR was significantly associated with efficacy of the following treatment, respectively. However, even patients with high pre-chemotherapy NLR achieved favorable OS if they had their NLR reduced by chemotherapy, whereas those with high pre-chemotherapy NLR yielded unfavorable OS if they had their NLR remained high after chemotherapy, suggesting that chemotherapy may have differential effect on the efficacy of subsequent pembrolizumab treatment in UC patients.

Enzalutamide in patients with non-metastatic castration-resistant prostate cancer after combined androgen blockade for recurrence following radical treatment in Japan (Japanese research for patients with non-metastatic castration-resistant prostate cancer-enzalutamide: JCASTRE-zero)-a prospective single-arm interventional study.

BACKGROUND: The effect of enzalutamide in patients with non-metastatic castration-resistant prostate cancer after combined androgen blockade, which represents a patient profile similar to real-world clinical practice in Japan, remains unknown. Therefore, we investigate the efficacy and safety of enzalutamide after combined androgen blockade for recurrence following radical treatment in Japanese patients with non-metastatic castration-resistant prostate cancer. METHODS: We analyzed 66 patients with non-metastatic castration-resistant prostate cancer after combined androgen blockade for recurrence following radical prostatectomy or radiation therapy who were prospectively enrolled from October 2015 to March 2018. They received enzalutamide 160 mg orally once daily until the protocol treatment discontinuation criteria were met. The primary endpoint was prostate-specific antigen-progression-free survival, defined as the time from enrollment to prostate-specific antigen-based progression or death from any cause. The secondary endpoints included overall survival, progression-free survival, metastasis-free survival, time to prostate-specific antigen progression, prostate-specific antigen response rate, chemotherapy-free survival, and safety assessment. RESULTS: The median observation period was 27.3 months. The median prostate-specific antigen-progression-free survival was 35.0 months (95% confidence interval, 17.5 to not reached). The median overall survival, median progression-free survival, median metastasis-free survival, and chemotherapy-free survival were not reached, with the corresponding 2-year rates being 91.6%, 67.1%, 72.4%, and 85.8%, respectively. The 50% prostate-specific antigen response rate was 88.9%, with the median time being 2.8 months. In total, 42.2% of the patients experienced adverse events, with malaise being the most common. CONCLUSIONS: Enzalutamide effectively manages non-metastatic castration-resistant prostate cancer after combined androgen blockade for recurrence following radical treatment. TRIAL REGISTRATION:  UMIN000018964, CRB6180007.

[Tumor Lysis Syndrome in a Patient with Germ Cell Tumor : A Case Report].

A 36-year-old man presented to our hospital with right scrotal swelling. A computed tomographic scan revealed a mass in the right scrotum, multiple masses in the lung and liver, and enlarged cervical, mediastinal, and retroperitoneal lymph nodes. After right high orchiectomy, he was diagnosed with nonseminomatous germ cell tumor (pT3N3M1b), with poor risk prediction according to the International Germ Cell Consensus classification. We started chemotherapy with bleomycin, etoposide, and cisplatin. Since serum alphafetoprotein (AFP) and human chorionic gonadotropin (HCG) levels did not decrease to normal levels, second-line chemotherapy with paclitaxel, ifosfamide, and cisplatin was administered. Six days after the start of treatment, the patient became unconscious, and his blood pressure decreased. Seven days later, blood tests revealed high uric acid levels, hyperphosphatemia, and increased creatinine. This was diagnosed as tumor lysis syndrome. Following diagnosis, continuous hemodiafiltration was started, and his condition gradually improved.

[Diagnostic Accuracy of Transperineal MRI-Ultrasound Fusion Biopsy at the Introduction Period].

Magnetic resonance imaging (MRI) ultrasound fusion biopsy is becoming popular owing to the better detection rate of clinically significant prostate cancer (csPCa). We retrospectively evaluated the accuracy of MRI-targeted biopsy during the period of introduction at a single academic center by comparing findings of its specimen and whole-mount histopathology. Between June 2018 and January 2021, 106 transperineal MRI-ultrasound fusion biopsies using BioJet software were performed. Among the cases, 15 subsequently underwent robotic-assisted laparoscopic radical prostatectomy and were eligible for analysis. This study included all regions of interest (ROIs) with a Prostate Imaging Reporting and Data System v2 category of 3 or greater on pre-biopsy MRI．For each lesion, grade group of MRI-targeted biopsy specimens and prostatectomy specimens were compared. From a total of 25 ROIs identified among 15 males, csPCa was found in 21 (84%) of the concordant locations of prostatectomy specimens. However, MRI-targeted biopsy could diagnose csPCa in only 12 (48%) of them. In the csPCa undetected group, the ROI volume was significantly smaller (median volume 0.23 ml vs 0.40 ml, p＝0.03). We also found that in cases where PCa was not detected through MRI-targeted biopsy, the biopsy sample length was significantly shorter (median length 9 mm vs 17 mm, p＝0.01). Our data suggest that failure of detecting PCa in MRI-targeted biopsy could be due to technical errors at the introduction period of the technique. A sufficient sampling length of 10 mm or more is desirable, especially for small lesions.

[The Safety of Laparoscopic Radical Cystectomy during Initial Phases in a Japanese Multicenter Cohort].

We evaluated the safety of laparoscopic radical cystectomy (LRC) during initial phases and its learning curve in a Japanese multicenter cohort by studying 436 patients who underwent LRC with no robot assistance at 10 institutions in Japan. We divided the patients into three groups according to cumulative surgical volume at each institution (first 10 cases, 11-30 cases, after 31 cases in each institution), and compared perioperative and pathologic variables among the three groups. The first, second, and third groups included 100, 166, 170 patients, respectively. The preoperative variables were similar in the three groups except for the rate of neoadjuvant chemotherapy. The methods of LRC procedure, such as urinary diversion, the extent of lymph node dissection, and concomitant urethrectomy or nephroureterectomy, were similar in the three groups. Mean operative time was 629, 562 and 531 minutes, respectively, and mean blood loss was 755, 650 and 435 ml, respectively. Both values decreased over time with the institution's experience. There was no significant difference among the three groups in the rate of positive surgical margin, the number of retrieved lymph nodes, and the rate of intra- and postoperative complications. LRC was safely performed during initial phases with an acceptable complication rate and without compromising oncological results, although operative time was longer and blood loss increased.

[A Case of Pulmonary Tumor Thrombotic Microangiopathy in Castration-Resistant Prostate Cancer].

A man aged 83 years under treatment with enzalutamide for castration-resistant prostate cancer presented with general malaise and exertional dyspnea. The underlying cause could not be identified by further investigations. On the 5th hospital day, he died due to a sudden exacerbation of dyspnea. The results of an autopsy indicated tumor emboli and stenosis of small pulmonary arteries with the fibrocellular intimal thickening, and therefore our final diagnosis was pulmonary tumor thrombotic microangiopathy.

[The Study of Surgical Outcome for Robotic-Assisted Laparoscopic Radical Prostatectomy : Experience of a Single Surgeon with 70 Initial Cases].

We investigated the surgical outcome for robotic-assisted laparoscopic radical prostatectomy (RALP) withinitial 70 prostate cancer cases performed by a single surgeon between June 2014 and May 2016. The surgeon had a previous experience of more than 400 cases of laparoscopic radical prostatectomy (LRP). Comparative study of the surgical outcome was made between the first 35 patients (group 1) and the second 35 patients (group 2). The console time without lymph node dissection significantly decreased from group 1 to 2 (193 min vs 158 min, p=0.002). Among specific 3 parts of the console operation (part 1 : until the bladder neck transection, part 2 : until the prostate removal and part 3 : urethrovesical anastomosis), duration of parts 1 and 2 similarly decreased witha significant difference of 0. 001 and 0. 002, respectively. Continence recovery rates 1 month after RALP were significantly higher in group 2 than in group 1 (group1 : 48.5% vs group 2 : 74.2%, p=0.02). Between groups 1 and 2, the positive surgical margin rates of both pT2 and pT3 were similar (group 1 : 20. 8 and 50. 0%, group 2 : 17. 2 and 50. 0%, respectively). The perioperative 8 complications (11.4%) were classified into Clavien-Dindo grades 1 and 2. Our surgical outcome of initial 70 RALP cases was considered as comparable to that reported from the high volume centers.

[Urethral Hemangioma with Repeated Urinary Retention by Posterection Hematuria].

A 73-year-old man presented to our hospital due to postejaculation gross hematuria and dysuria. Three months after onset, urinary retention occurred repeatedly. Under general anesthesia, cystourethroscopy following drug-induced erection was performed. A solitary sessile lesion with varicosis was found between the verumontanum and external sphincter. The tumor was resected endoscopically and recurrence was not observed during the follow-up period. Histological examination revealed a cavernous hemangioma of the urethra. Urologists should keep in mind that urethral hemangioma can be a cause of hematuria after erection or ejaculation.

[Laparoscopic resection of a retroperitoneal müllerian cyst: a case report].

A 51-year-old woman had a cystic mass in the retroperitoneal space, below the left kidney, which was incidentally detected at a medical check-up. The size of the mass was 6 cm in diameter, which was similar to that obtained by magnetic resonance imaging 4 years ago. We followed the case and found that the mass was slightly enlarged a year later. Because malignancy could not be ruled out, we performed a laparoscopic tumor excision. Histologically, the cyst was diagnosed as a Müllerian cyst, and there was no evidence of malignancy. Retroperitoneal Müllerian cyst is a rare tumor. Sixteen cases have been reported previously and this is the fourth case of a laparoscopic excision.

Vision-based estimation of manipulation forces by deep learning of laparoscopic surgical images obtained in a porcine excised kidney experiment.

In robot-assisted surgery, in which haptics should be absent, surgeons experience haptics-like sensations as "pseudo-haptic feedback". As surgeons who routinely perform robot-assisted laparoscopic surgery, we wondered if we could make these "pseudo-haptics" explicit to surgeons. Therefore, we created a simulation model that estimates manipulation forces using only visual images in surgery. This study aimed to achieve vision-based estimations of the magnitude of forces during forceps manipulation of organs. We also attempted to detect over-force, exceeding the threshold of safe manipulation. We created a sensor forceps that can detect precise pressure at the tips with three vectors. Using an endoscopic system that is used in actual surgery, images of the manipulation of excised pig kidneys were recorded with synchronized force data. A force estimation model was then created using deep learning. Effective detection of over-force was achieved if the region of the visual images was restricted by the region of interest around the tips of the forceps. In this paper, we emphasize the importance of limiting the region of interest in vision-based force estimation tasks.

Development of deep learning model for diagnosing muscle-invasive bladder cancer on MRI with vision transformer.

Rationale and objectives: To develop and validate a deep learning (DL) model to automatically diagnose muscle-invasive bladder cancer (MIBC) on MRI with Vision Transformer (ViT). Materials and methods: This multicenter retrospective study included patients with BC who reported to two institutions between January 2016 and June 2020 (training dataset) and a third institution between May 2017 and May 2022 (test dataset). The diagnostic model for MIBC and the segmentation model for BC on MRI were developed using the training dataset with 5-fold cross-validation. ViT- and convolutional neural network (CNN)-based diagnostic models were developed and compared for diagnostic performance using the area under the curve (AUC). The performance of the diagnostic model with manual and auto-generated regions of interest (ROImanual and ROIauto, respectively) was validated on the test dataset and compared to that of radiologists (three senior and three junior radiologists) using Vesical Imaging Reporting and Data System scoring. Results: The training and test datasets included 170 and 53 patients, respectively. Mean AUC of the top 10 ViT-based models with 5-fold cross-validation outperformed those of the CNN-based models (0.831 ± 0.003 vs. 0.713 ± 0.007-0.812 ± 0.006, p < .001). The diagnostic model with ROImanual achieved AUC of 0.872 (95 % CI: 0.777, 0.968), which was comparable to that of junior radiologists (AUC = 0.862, 0.873, and 0.930). Semi-automated diagnosis with the diagnostic model with ROIauto achieved AUC of 0.815 (95 % CI: 0.696, 0.935). Conclusion: The DL model effectively diagnosed MIBC. The ViT-based model outperformed CNN-based models, highlighting its utility in medical image analysis.

Spatial Pattern of Intraprostatic Recurrence after Definitive External-Beam Radiation Therapy for Prostate Cancer: Implications for Focal Boost to Intraprostatic Dominant Lesion.

Purpose: We retrospectively investigated spatial pattern associations between primary and recurrent tumor sites after definitive external-beam radiation therapy (EBRT) for prostate cancer, using positron emission tomography/computed tomography (PET/CT) with a prostate-specific membrane antigen (PSMA)-targeted probe, 18F-FSU-880. Methods and Materials: We used data from our prior phase 2 trial involving patients who received PET/CT with 18F-FSU-880, which was designed to evaluate the tumor detection efficacy of PSMA-PET/CT for recurrent prostate cancer. Data from patients with local intraprostatic recurrence detected by PSMA-PET/CT after definitive EBRT were retrospectively analyzed. The prostate and seminal vesicles were divided into 14 sections. Two diagnostic radiologists separately re-evaluated the intraprostatic location of the primary tumor on magnetic-resonance imaging and that of the recurrent tumor on PSMA-PET/CT, respectively, and the rate of overlap between primary and recurrent tumors was calculated. The overlap rate was defined as "the number of sections that overlapped between the primary tumor and recurrent tumor" divided by "the total number of sections of recurrent tumor". A recurrent tumor was considered to be at the same location as the primary tumor when the overlap rate was equal to or greater than 75%, and a partial overlap was defined as an overlap rate between 25 and 74%. Results: Twelve patients had local recurrence detected by PSMA-PET/CT. The median time to diagnosis of local recurrence was 9.1 (range, 2.2-12.3) years after definitive EBRT. The recurrent tumor was detected at the same location in 25.0%, and a partial overlap was noted in 41.7%. Conclusions: Local intraprostatic recurrence after definitive EBRT often occurs at the same site or at a partially overlapping site adjacent to the primary intraprostatic dominant lesion. Our results support the merit of focal dose-escalation for intraprostatic dominant lesions in definitive EBRT.

Comparison of Cabozantinib and Axitinib as Second-line Therapy After Nivolumab Plus Ipilimumab in Patients With Metastatic Clear Cell Renal Cell Carcinoma: A Comparative Analysis of Retrospective Real-world Data.

BACKGROUND: To date, no studies have compared the treatment outcomes of second-line therapies in patients with metastatic clear cell renal cell carcinoma (ccRCC). This study retrospectively evaluated the efficacy of cabozantinib and axitinib as second-line treatments in patients with metastatic ccRCC who previously received immune-oncology combination therapy. PATIENTS AND METHODS: Patients with metastatic ccRCC treated with cabozantinib and axitinib as second-line therapy after nivolumab-ipilimumab treatment were identified among 243 patients with RCC treated between August 1, 2018 and January 31, 2022 at 34 institutions belonging to the Japanese Urological Oncology Group. Patients were assessed for treatment outcomes, including progression-free survival (PFS), overall survival, objective response rate (ORR), and incidence rate of treatment-related adverse events (AEs). RESULTS: Forty-eight patients treated with cabozantinib and 60 treated with axitinib as second-line therapy after nivolumab-ipilimumab treatment for metastatic ccRCC were identified. The median PFS (95% confidence interval) was 11.0 months (9.0-16.0) with cabozantinib and 9.5 months (6.0-13.0) with axitinib. The ORRs were 37.5% (cabozantinib) and 38.3% (axitinib). The rates of any-grade AEs and grade ≥3 AEs were 79.2% (cabozantinib) versus 63.3% (axitinib; P = .091) and 35.4% (cabozantinib) versus 23.3% (axitinib; P = .202), respectively. In the poor-risk group, PFS was longer in the cabozantinib group than in the axitinib group (P = .033). CONCLUSION: The efficacy and safety of cabozantinib and axitinib were comparable. In the poor-risk group, cabozantinib was more effective than axitinib. These findings provide valuable insights into the selection of second-line treatment options after nivolumab-ipilimumab treatment in patients with metastatic ccRCC.

Automatic segmentation of bladder cancer on MRI using a convolutional neural network and reproducibility of radiomics features: a two-center study.

This study aimed to develop a versatile automatic segmentation model of bladder cancer (BC) on MRI using a convolutional neural network and investigate the robustness of radiomics features automatically extracted from apparent diffusion coefficient (ADC) maps. This two-center retrospective study used multi-vendor MR units and included 170 patients with BC, of whom 140 were assigned to training datasets for the modified U-net model with five-fold cross-validation and 30 to test datasets for assessment of segmentation performance and reproducibility of automatically extracted radiomics features. For model input data, diffusion-weighted images with b = 0 and 1000 s/mm2, ADC maps, and multi-sequence images (b0-b1000-ADC maps) were used. Segmentation accuracy was compared between ours and existing models. The reproducibility of radiomics features on ADC maps was evaluated using intraclass correlation coefficient. The model with multi-sequence images achieved the highest Dice similarity coefficient (DSC) with five-fold cross-validation (mean DSC = 0.83 and 0.79 for the training and validation datasets, respectively). The median (interquartile range) DSC of the test dataset model was 0.81 (0.70-0.88). Radiomics features extracted from manually and automatically segmented BC exhibited good reproducibility. Thus, our U-net model performed highly accurate segmentation of BC, and radiomics features extracted from the automatic segmentation results exhibited high reproducibility.

Analysis of trifecta outcomes in a single center with robot-assisted partial nephrectomy for T1b renal tumors.

INTRODUCTION: This study was performed to investigate the preoperative factors associated with difficulty achieving trifecta in robot-assisted partial nephrectomy for clinical T1b renal cell carcinoma. METHODS: Among 187 patients who underwent robot-assisted partial nephrectomy at our hospital from March 2012 to February 2022, we retrospectively examined 30 patients with unilateral single clinical T1b renal cell carcinoma with at least 6 months of postoperative follow-up, excluding patients with hereditary disease. The following factors were examined in detail: patient-related factors, perioperative factors, surgical techniques, tumor factors, and R.E.N.A.L. nephrometry scores. We examined the preoperative factors associated with difficulty achieving trifecta. A positive surgical margin was pathologically defined as the presence of tumor cells at the margin of the resected specimen or visually defined as intraoperative tumor incision or pseudocapsular damage. RESULTS: Of the 30 patients in this study, 12 achieved trifecta and 18 did not. The reasons for not achieving trifecta were a warm ischemia time of >25 min (66.7%), positive surgical margin (23.3%), and Clavien-Dindo grade ≥3 complications (13.3%) (with overlapping factors). No patients had a pathologically positive surgical margin. Visually positive surgical margins were confirmed by the surgical records and surgical videos. Achieving trifecta was challenging in the multivariate analysis when the "L" component of the R.E.N.A.L. nephrometry score was ≥2 points. CONCLUSION: A preoperative "L" component of ≥2 points in the R.E.N.A.L. nephrometry score was associated with difficulty achieving trifecta.