Patient-specific simulations and navigation systems for partial nephrectomy.

Partial nephrectomy (PN) is the standard treatment for T1 renal cell carcinoma. PN is affected more by surgical variations and requires greater surgical experience than radical nephrectomy. Patient-specific simulations and navigation systems may help to reduce the surgical experience required for PN. Recent advances in three-dimensional (3D) virtual reality (VR) imaging and 3D printing technology have allowed accurate patient-specific simulations and navigation systems. We reviewed previous studies about patient-specific simulations and navigation systems for PN. Recently, image reconstruction technology has developed, and commercial software that converts two-dimensional images into 3D images has become available. Many urologists are now able to view 3DVR images when preparing for PN. Surgical simulations based on 3DVR images can change surgical plans and improve surgical outcomes, and are useful during patient consultations. Patient-specific simulators that are capable of simulating surgical procedures, the gold-standard form of patient-specific simulations, have also been reported. Besides VR, 3D printing is also useful for understanding patient-specific information. Some studies have reported simulation and navigation systems for PN based on solid 3D models. Patient-specific simulations are a form of preoperative preparation, whereas patient-specific navigation is used intraoperatively. Navigation-assisted PN procedures using 3DVR images have become increasingly common, especially in robotic surgery. Some studies found that these systems produced improvements in surgical outcomes. Once its accuracy has been confirmed, it is hoped that this technology will spread further and become more generalized.

Significant response to nivolumab for metastatic chromophobe renal cell carcinoma with sarcomatoid differentiation: a case report.

BACKGROUND: The treatment of advanced or metastatic renal cell carcinoma (RCC) has drastically changed since the approval of immune checkpoint therapy. Nivolumab is a treatment option for patients with metastatic RCC, previously treated with targeted antiangiogenic therapy. The efficacy of nivolumab for patients with RCC was established by the Checkmate 025 clinical trial. Chromophobe RCC (CRCC) represents around 5% of RCC cases, but non-clear cell RCC (non-ccRCC) subtypes were excluded from the Checkmate 025 clinical trial. We report a case in which the use of nivolumab as the seventh-line therapy elicited a significant response in the treatment of metastatic CRCC with sarcomatoid differentiation. CASE PRESENTATION: We report a case of a 41-year-old woman with metastatic CRCC with sarcomatoid differentiation. She was treated with sunitinib, pazopanib, everolimus, sorafenib, axtinib, and temsirolimus, but treatment was discontinued because of disease progression or strong adverse events. Seventh-line treatment with nivolumab was initiated and significant clinical improvement was noted after 4 cycles. The treatment was well-tolerated with no significant side effects and the patient continues with nivolumab treatment at present. CONCLUSIONS: Nivolumab may be an attractive treatment option for non-ccRCC patients with sarcomatoid differentiation that exhibited aggressive characteristics and poor prognosis. Further investigation is warranted.

Hereditary leiomyomatosis and renal cell cancer without cutaneous manifestations in two Japanese siblings.

Hereditary leiomyomatosis and renal cell cancer is a rare genetic disorder characterized by cutaneous and uterine leiomyomatosis, and an aggressive type 2 papillary renal cell carcinoma. The disease is caused by a germline mutation in the fumarate hydratase gene. We report a familial hereditary leiomyomatosis and renal cell cancer in two siblings. A 34-year-old woman underwent nephrectomy for treatment of a renal cell carcinoma. The patient's sister had been diagnosed with renal cell carcinoma at 28 years-of-age and died of the disease. Neither sister had apparent skin tumors. Histopathology of the renal cell carcinomas of the siblings showed tubulocystic and papillary architectures with high nuclear grades. Immunostaining showed no fumarate hydratase expression in either tumor. Genomic DNA sequencing of the patient showed a germline mutation in the fumarate hydratase gene (c.675delT). Although there is no epidemiological information on Asian hereditary leiomyomatosis and renal cell cancer, physicians should be aware that typical cutaneous leiomyomatosis might not always be present in patients with hereditary leiomyomatosis and renal cell cancer.

[Renal Cell Carcinoma with Retroperitoneal Metastases and Renal Invasion from Breast Cancer : A Case Report].

A 67-year-old female was hospitalized with back pain. Computed tomography (CT) incidentally revealed a tumor in her left kidney tumor (33 mm) and bilateral breast tumors. She underwent a breast biopsy and was diagnosed with breast cancer (invasive lobular cancer, cT2N0M0). The renal tumor was suspected to be clear cell carcinoma, cT1aN0M0, based on contrast-enhanced CT. Surgery was considered necessary for both the breast cancer and renal tumor. First, laparoscopic radical nephrectomy was performed for the renal tumor. However, the lateroconal fascia adhered strongly to the perirenal fat, and so simple nephrectomy was carried out after conversion to open surgery. The perirenal fat was also excised after the nephrectomy. A histopathological examination revealed clear cell carcinoma and renal invasion by invasive lobular cancer cells. Also, scattered metastases were detected in the perirenal fat and the lateroconal fascia. So, it was considered that retroperitoneal metastases from the breast cancer had directly invaded the kidney. After the operation, the patient received hormonal therapy for her breast cancer, and she was still alive and symptom-free 5 months after the operation.

[Additional administration of dutasteride in patients with benign prostatic hyperplasia who did not respond sufficiently to α1-adrenoceptor antagonist : investigation of clinical factors affecting the therapeutic effect of dutasteride].

We performed additional administration of dutasteride in patients who did not respond sufficiently to α1-adrenoceptor antagonist treatment for lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) (LUTS/BPH). Among 76 registered patients, efficacy was analyzed in 58 patients. International Prostate Symptom Score (IPSS), subscores for voiding and storage symptoms and quality of life (QOL) on the IPSS, and Overactive Bladder Symptom Score (OABSS) were all significantly improved from the third month of administration compared to the time of initiating additional administration of dutasteride. Additional administration of dutasteride also significantly reduced prostate volume, and residual urine with the exception of the sixth month after administration. Age at initiation of administration and voiding symptom subscore on the IPSS were clinical factors affecting the therapeutic effects of dutasteride. The rate of improvement with treatment decreased with increasing age at initiation of dutasteride administration, and increased as voiding symptom subscore on the IPSS increased. Therefore, additional administration of dutasteride appears useful for cases of LUTS/BPH in which a sufficient response is not achieved with α1-adrenoceptor antagonist treatment. Because patients who have severe voiding symptoms or begin dutasteride at an early age may be expected to respond particularly well to dutasteride in terms of clinical efficacy, they were considered to be suitable targets for additional administration.

[A case of pneumomediastinum during BEP (bleomycin, etoposide, cisplatin) chemotherapy for testicular cancer].

We report a case of drug-induced pneumomediastinum by bleomycin in testicular cancer, which is extremely rare ; to our knowledge, only 3 cases have been reported. A 28-year-old man presented with a left testicular mass. He underwent radical left inguinal orchiectomy that demonstrated a seminoma, pT3N0M0. Ten months after surgery, para-aortic lymph node metastasis appeared, and he received three cycles of bleomycin, etoposide and cisplatin (BEP) chemotherapy. On day 13 of the fourth course of BEP, he complained of snowball crepitation of the neck and computed tomography revealed subcutaneous emphysema, extensive mediastinal air, and intraspinal air accumulation without pneumothorax. The pneumomediastinum and subcutaneous emphysema tended to deteriorate until 15 days after the onset of pneumomediastinum, but fortunately he had no signs or symptoms of infection. These findings resolved spontaneously after 1 month.

Comparative analyses define differences between BHD-associated renal tumour and sporadic chromophobe renal cell carcinoma.

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome, caused by germline alteration of folliculin (FLCN) gene, develops hybrid oncocytic/chromophobe tumour (HOCT) and chromophobe renal cell carcinoma (ChRCC), whereas sporadic ChRCC does not harbor FLCN alteration. To date, molecular characteristics of these similar histological types of tumours have been incompletely elucidated. METHODS: To elucidate renal tumourigenesis of BHD-associated renal tumours and sporadic renal tumours, we conducted whole genome sequencing (WGS) and RNA-sequencing (RNA-seq) of sixteen BHD-associated renal tumours from nine unrelated BHD patients, twenty-one sporadic ChRCCs and seven sporadic oncocytomas. We then compared somatic mutation profiles with FLCN variants and RNA expression profiles between BHD-associated renal tumours and sporadic renal tumours. FINDINGS: RNA-seq analysis revealed that BHD-associated renal tumours and sporadic renal tumours have totally different expression profiles. Sporadic ChRCCs were clustered into two distinct clusters characterized by L1CAM and FOXI1 expressions, molecular markers for renal tubule subclasses. Increased mitochondrial DNA (mtDNA) copy number with fewer variants was observed in BHD-associated renal tumours compared to sporadic ChRCCs. Cell-of-origin analysis using WGS data demonstrated that BHD-associated renal tumours and sporadic ChRCCs may arise from different cells of origin and second hit FLCN alterations may occur in early third decade of life in BHD patients. INTERPRETATION: These data further our understanding of renal tumourigenesis of these two different types of renal tumours with similar histology. FUNDING: This study was supported by JSPS KAKENHI Grants, RIKEN internal grant, and the Intramural Research Program of the National Institutes of Health (NIH), National Cancer Institute (NCI), Center for Cancer Research.

[A case of retroperitoneal angioleiomyoma resected by laparoscopy].

A retroperitoneal angioleiomyoma was incidentally detected in a 56-year-old woman during an examination of cardiovascular disease, and referred to the department of urology. Computed tomography (CT) showed a solid tumor approximately 3 cm in diameter, enhanced heterogeneously adjacent to the right adrenal and renal vein on magnetic resonance imaging the tumor showed a low intensity in the T1-weighted image and high intensity in T2-weighted image. These radiographic findings suggested a retroperitoneal tumor such as paraganglioma, angioma. Furthermore, because she was a carrier of Human Adult T Cell Leukemia Virus-I (HTLV-I) this tumor was suspected to have relevance to malignant lymphoma. We performed laparoscopic surgical excision of the tumor. Pathlogical diagnosis was an angioleiomyoma. Angioleiomyoma is a rare type of leiomyoma originating from smooth muscle and containing thick-walled vessels. Only a few cases of retroperitoneal angioleiomyoma have been reported.

[A case of retroperitoneal angiosarcoma effectively treated with recombinant interleukin-2].

Angiosarcoma is rare and highly malignant vascular neoplasm, and primary retroperitoneal angiosarcoma is extremely rare. Preoperative diagnosis is very difficult because there are no specific imaging features, and definitively effective treatment has not yet been established. We recently treated a patient with primary retroperitoneal angiosarcoma in which a prompt and exact diagnosis was difficult to obtain. One month after surgery, local recurrence appeared, but salvage immunotherapy using recombinant interleukin-2 (rIL-2) showed good efficacy, and the patient obtained complete response. Here we report this rare case of angiosarcoma. A 60-year-old woman with abdominal pain was diagnosed with a left retroperitoneal mass on CT scan. The tumor was about 9 cm in diameter and positioned above the left kidney. Further study using MRI, 131I-MIBG scintigraphy, and enhanced CT suggested chronic expanding hematoma and the patient underwent surgical resection. Histopathological diagnosis was primary retroperitoneal angiosarcoma based on positive staining for VIII factor, CD31, CD34, and p53. One month after surgery, FDG-PET revealed local recurrence adjacent to the psoas major. We initiated salvage immunotherapy using rIL-2. The patient was treated effectively and achieved complete response. She is alive and well 19 months after surgery and rIL-2 treatment.

[Clinical comparison between microporous polysaccharide hemispheres (MPH) and fibrin glue].

PURPOSE: Nephron-sparing surgery for small renal tumors has gained acceptance in an attempt to preserve renal function while achieving a level of cancer control equivalent to that obtained by radical nephrectomy. Moreover, laparoscopic partial nephrectomy (LPN) has been applied to partial nephrectomy because of it is less invasive. However, LPN is a technically complex procedure and has more potential for complications than open partial nephrectomy (OPN). Using hemostatic agents is one of the options to avoid complications during LPN. Microporous polysaccharide hemispheres (MPH) are an absorbable hemostatic powder produced from purified potato starch. We compare the efficacy of this new hemostatic agent, MPH and the standard hemostatic agent, fibrin glue. METHODS: Between January 2007 and March 2011, 55 LPNs for suspected malignancy were completed by a single surgeon in Yokohama City University Hospital. We compare two sequential groups of patients: group A consisted of 12 patients in whom MPH was used (age 41-77, mean age 59.7, male: female = 10 : 2) and group B consisted of 43 patients in whom fibrin glue was used (age 22-79, mean age 60.3, male: female = 31 : 12), retrospectively. These agents (MPH and fibrin glue) were applied to the partial nephrectomy bed before tying a suture in parenchymal suturing and after the renal hilum was unclamped. RESULTS: The MPH group showed significantly less mean estimated blood loss (25.6 vs. 86.3 ml; p = 0.036). There was no significant difference in surgical duration, ischemic time or urine leakage. Postoperative complications occurred in two patients in group B, but there were no postoperative complications in group A. CONCLUSIONS: MPH is available as an adequate hemostatic agent during LPN. There was no significant difference in the incidence of postoperative complications between MPH and fibrin glue.

Single-cell transcriptomes underscore genetically distinct tumor characteristics and microenvironment for hereditary kidney cancers.

Our understanding of how each hereditary kidney cancer adapts to its tissue microenvironment is incomplete. Here, we present single-cell transcriptomes of 108,342 cells from patient specimens including from six hereditary kidney cancers. The transcriptomes displayed distinct characteristics of the cell of origin and unique tissue microenvironment for each hereditary kidney cancer. Of note, hereditary leiomyomatosis and renal cell carcinoma (HLRCC)-associated kidney cancer retained some characteristics of proximal tubules, which were completely lost in lymph node metastases and present as an avascular tumor with suppressed T cells and TREM2-high macrophages, leading to immune tolerance. Birt-Hogg-Dubé (BHD)-associated kidney cancer exhibited transcriptomic intratumor heterogeneity (tITH) with increased characteristics of intercalated cells of the collecting duct and upregulation of FOXI1-driven genes, a critical transcription factor for collecting duct differentiation. These findings facilitate our understanding of how hereditary kidney cancers adapt to their tissue microenvironment.

[A renal cell carcinoma metastasis to the contralateral perirenal fat : a case report].

A 53-year-old woman was admitted with right lower abdominal pain in November 1993. Computed tomography (CT) revealed a right renal tumor, suspected to be a renal cancer. She underwent right radical nephrectomy in December 1993. The pathological diagnosis was clear cell carcinoma, pT2, grade 2. In May 2006, follow-up CT showed a tumor arising from the left perirenal fat. Laparoscopic tumor excision was performed in August 2006. The pathological diagnosis was metastatic clear cell carcinoma.

[ARTIFICIAL URINARY SPHINCTER IMPLANTATION AFTER ILEAL NEOBLADDER RECONSTRUCTION: A CASE REPORT].

A 62-year-old man was referred to our department for artificial urinary sphincter (AUS) implantation as treatment for total incontinence after laparoscopic radical prostatectomy. Preoperative cystoscopy revealed bladder tumor that was proven to be high-grade micropapillary urothelial carcinoma by transurethral resection. We performed radical cystectomy with ileal neobladder reconstruction, followed by AUS implantation to treat incontinence. The AUS implantation procedure was performed 5 months after total cystectomy and resulted in significant continence recovery. To date, AUS implantation after neobladder reconstruction has not been reported in Japan, although some case series have described this procedure overseas. In our view, AUS implantation is a useful therapeutic option for incontinence in patients undergoing neobladder reconstruction.

Estimating body weight of pigs from posture analysis using a depth camera.

A noninvasive method for estimating the body weight (BW) of a pig considering its posture using a low-cost depth camera (Kinect v2) was proposed. A total of 150 pigs were used, and 738 depth images (point clouds) were obtained for them. The pig "volume" was calculated from the pig point cloud, and it was found to have a very high correlation to BW. To evaluate the posture of a pig quantitatively, seven posture angles were calculated based on the "spine" extracted from a pig point cloud. We found the posture angles representing the height of the head position correlated with the accuracy of BW estimation using the "volume." Based on this finding, we proposed an "adjusted volume," which was adjusted based on the relationship between the posture angles and the estimation error. The BW of pigs was estimated using the simple regression model with the "adjusted volume," and the MAPE and RMSPE were 4.87% and 6.13%, respectively. The accuracy of the suggested model was similar to that of the volume-based estimation models of other studies that used only data with an appropriate pig posture for BW estimation.

Re-Challenging with Nivolumab in Metastatic Renal Cell Carcinoma After Immune-Related Interstitial Pneumonia: A Case Report.

BACKGROUND The efficacy and safety of re-challenge with immune checkpoint inhibitors after immune-related adverse events have not been established. We report a case of successful re-administration of nivolumab in metastatic renal cell carcinoma after discontinuation due to immune-related adverse events. CASE REPORT Laparoscopic nephrectomy was performed on a 52-year-old man diagnosed with renal cell carcinoma pT1bN0M0. After surgery, left adrenal and lung metastases appeared. Nivolumab was administered as a sixth-line therapy, and he achieved a partial response, but interstitial pneumonia occurred. He was diagnosed with grade 2 immune-related adverse events, and nivolumab treatment was discontinued. Interstitial pneumonia was well controlled by steroids. He maintained a partial response for a long time, and the lung metastases disappeared 7 months after discontinuation. However, bilateral lung metastases reappeared 10 months after the discontinuation. We decided to re-administer nivolumab, while carefully monitoring the patient and fully explaining the risk of recurrence of immune-related adverse events. After 5 cycles of re-administration, computed tomography revealed a reduction in metastases without re-activation of interstitial pneumonia. He experienced a grade 1 fever the day after re-administration, but continued nivolumab therapy without other adverse events. After 7 cycles of re-administration, the lung metastases increased, and nivolumab treatment was terminated. Two months later, a grade 2 interstitial pneumonia recurred, but improved rapidly with oral steroids. CONCLUSIONS For patients who have discontinued immune checkpoint inhibitors due to immune-related adverse events, re-challenge of immune checkpoint inhibitors may be an option after explaining the risk of relapse of immune-related adverse events.

Outcome of Palliative Urinary Diversion and Observation for Malignant Extrinsic Ureteral Obstruction.

Background: Urologists are often referred to manage the extrinsic malignant ureteral obstruction (MUO) caused by nonurological malignancies. Usually palliative urinary diversion (ureteral stent or nephrostomy) will be performed; however, in the cases of no symptom or poor prognosis, observation (OBS) without any intervention will be selected. There are few reports about outcome of the OBS policy for MUO. Objective: To evaluate the outcome of palliative urinary diversion or OBS for MUO. Design: We retrospectively reviewed the selection of treatment and the prognosis. Setting/Subjects: A total of 151 cases were introduced to our department as MUO between April 2011 and December 2016. Measurements: The patients were divided to immediate palliative urinary diversion (immediate-DIV) or OBS. The latter patients were subdivided to OBS followed by deferred palliative urinary diversion (deferred-DIV), and observation only (OBS-only). Results: There was no significant difference between immediate-DIV and OBS about overall survival (OS) from the consultation. In OBS group, deferred-DIV did not prolong prognosis from the consultation more than OBS-only. In the same way, there was no significant difference between immediate-DIV and deferred-DIV in OS from the intervention. Unfavorable prognostic factors for OS were lack of anticancer treatment after consultation, symptoms of MUO, and gastrointestinal cancer. When we classified the patients by these factors, the group with three factors showed significantly poorer prognosis than the others. Conclusion: Immediate-DIV or OBS did not influence the prognosis in the whole patients. Three prognostic factors that will be judged by urologists easily might be useful for the indication and timing of palliative urinary diversion.

[A CASE OF EXTRASKELETAL EWING'S SARCOMA IN THE RETROPERITONEUM].

A 23-year-old man was admitted to our hospital with a huge pelvic tumor. MRI showed a tumor mixed with a solid component and polycystic cyst with maximum diameter of about 20 cm. Percutaneous tumor needle biopsy was performed and diagnosis was Ewing sarcoma. At that time, operation is extremely difficult, so the neoadjuvant chemotherapy with ifosfamide, etoposide, Adriamycin, and vincristine were administered. After 6 courses, MRI showed tumor reduction to maximum diameter of 10 cm. We planned tumor resection with total cystectomy for radical resection, but we also tried to preserve bladder considering the young age and quality of life. Although the bladder was partially resected, tumor resection was succeeded without removing surrounding organs. Histopathological examination revealed viable cells remained, but more than 95% was disappeared and the surgical margins were negative. Here we report a case of extra skeletal Ewing sarcoma in the retroperitoneum that was treated with chemotherapy and surgery without scarifying surrounding organs.

Comparative effectiveness of surgery and radiotherapy for survival of patients with clinically localized prostate cancer: A population-based coarsened exact matching retrospective cohort study.

Radical prostatectomy and radiotherapy are currently the main treatment options for localized prostate cancer. However, no large cohort study comparing surgery and radiation has been performed in Japan or Asia. The objective of the current study was to compare the survival outcomes of patients with clinically localized prostate cancer and in elderly and young patients receiving surgery and radiotherapy. The survival outcomes of patients with localized prostate cancer (age at diagnosis ≤79 years, clinical T1-3) initially treated with surgery or radiotherapy were retrospectively analyzed. Data were collected from the population-based cancer registry of the Kanagawa Prefecture, Japan. A 1:1 coarsened exact matching of age at diagnosis, clinical T stage and cancer differentiation was performed between the two treatment groups. Patients were also categorized into two subgroups by age using a cutoff of 70 years for analysis. The cohort comprised 4,810 patients aged 50-79 years. No significant difference in cancer-specific survival (CSS) was observed between the two groups (P=0.612). However, the surgery group had significantly better overall survival (OS; P=0.004). When stratified for age, similar tendencies were observed in the elderly group (aged 70-79 years; CSS, P=0.961 and OS, P=0.007). No significant difference in either CSS or OS was identified in the younger group (P=0.550 and P=0.408, respectively). Intrinsic deaths were more likely to occur in elderly patients treated with radiotherapy than those undergoing surgery (69.3 vs. 78.2%; P=0.128). The results indicated that surgery provided significantly better OS than radiotherapy, particularly among the elderly. However, no significant difference was observed in CSS. These results should be interpreted with caution, given that some important factors were unavailable in the present study, such as prostate-specific antigen values and Gleason scores. Prospective trials evaluating these therapies are warranted.

A lower psoas muscle volume was associated with a higher rate of recurrence in male clear cell renal cell carcinoma.

BACKGROUND: Sarcopenia is defined as a low skeletal muscle volume. Recent studies have reported that sarcopenia is associated with a poor prognosis in various cancers. The purpose of this study is to evaluate the correlation between the psoas muscle volume and recurrence-free survival in patients with localized clear cell renal cell carcinoma (ccRCC). METHODS: A total of 316 male patients with localized ccRCC who underwent radical nephrectomy at Yokohama City University Hospital (Yokohama, JAPAN) and Kanagawa Cancer Center (Yokohama, JAPAN) between 2002 and 2018 were enrolled in this study. The psoas muscle index (PMI) was calculated by normalizing the psoas muscle area on the contralateral side of the tumor on axial CT, which was calculated at the level of L4 (mm2) divided by the square of the body height (m2). We divided patients into two groups based on the median PMI (409.64mm2/m2). RESULTS: The lower PMI group showed poorer recurrence-free survival (RFS) than the higher PMI group (p = 0.030). Regarding 5-year RFS, a lower PMI was a significant predictor of recurrence (p = 0.022, hazard ratio (HR): 2.306) and a multivariate analysis revealed that a lower PMI (4 cm (p = 0.044, HR: 2.341), and pathological stage >2 (p<0.001, HR: 3.660) were independent risk factors for poor RFS. CONCLUSIONS: The presence of sarcopenia (lower PMI) was found to be associated with poor RFS in male ccRCC patients. The PMI might serve as a measure of patient frailty and might be useful for prognostic risk stratification in ccRCC.

C-reactive protein at 1 month after treatment of nivolumab as a predictive marker of efficacy in advanced renal cell carcinoma.

PURPOSE: Nivolumab is part of the standard therapy for mRCC. Although deep and long-lasting responses are seen in some patients, the benefit of treatment is limited to some patients and the majority of patients will experience disease progression. PD-L1 is still under evaluation as a predictive biomarker and there is an urgent need to establish biomarkers for the treatment of nivolumab. Here, we investigate C-reactive protein (CRP) at 1 month after treatment of nivolumab as a target to predict the response of patients with metastatic renal cell carcinoma (mRCC) to nivolumab. METHODS: After approval of the study by our institutional review board, 64 patients with mRCC who underwent nivolumab treatment at Kanagawa Cancer Center and Yokohama City University Hospital were enrolled. The patient characteristics, blood examination data at start of nivolumab treatment and 1 month after treatment, response to treatment and progression-free survival (PFS) were evaluated. Tumour responses were assessed according to both the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and the immune RECIST (iRECIST) criteria. Moreover, in 12 patients who agreed to an additional blood examination, several serum inflammatory factors were investigated and their correlation with CRP level was examined. RESULTS: The median follow-up was 8.3 months (range 0.2-29.8 months). The median PFS period was 4.5 months and the median immune-PFS (iPFS) period was 5.3 months. RECIST 1.1 criteria underestimated the benefits of nivolumab in four (6.4%) cases. Multivariate analyses showed that an Eastern Cooperative Oncology Group performance status (≥ 2) at start of treatment and CRP level at 1 month after treatment (≥ 1.5 mg/dL) were independent risk factors for a poor iPFS of nivolumab. The CRP level at baseline was not an independent prognostic factor for iPFS. When compared with the responder group (iCR + iPR + iSD), the non-responder group (iPD) had a significantly higher CRP levels at 1 month after treatment (p < 0.001). In the responder group, there was significant decrease in the CRP level after nivolumab treatment when compared with the baseline (p = 0.002), whereas there was a significant increase in the non-responder group (p = 0.019). Even patients with high baseline CRP (≥ 1.5 mg/dL) obtained good iPFS if CRP was decreased (< 1.5 mg/dL) 1 month after treatment. In addition, the classification of Glasgow prognostic score (GPS), which is a cumulative prognostic score based on CRP and albumin, was a significant predictor for iPFS. A strong correlation (|r| > 0.7) with CRP level at 1 month after treatment was seen for sCD163, IL-34, MMP-1, MMP-2, osteopontin, sTNF-R1 and sTNF-R2. Of these, MMP-1 and MMP-2 were not correlated at baseline. CONCLUSION: Our results indicated that the CRP level at 1 month after treatment with nivolumab appears to be a promising predictive biomarker for response to nivolumab treatment in patients with mRCC. It is clinically useful to be able to predict the effect within a short period. Further prospective trials are needed to prove these preliminary findings.