Background: Metastatic renal cell carcinoma (mRCC) is an aggressive cancer characterised by an increased recurrence rate and an inadequate response to treatment. This study aimed to investigate the importance of the neutrophil-to-lymphocyte ratio (NLR) as a prognostic marker for long-term survival in patients with mRCC. Methods: We retrospectively analysed data from 74 patients with mRCC treated at our medical centre with tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs). We evaluated the predictive value of NLR for overall survival (OS) in these patients. Results: The median OS was 5.1 months in the higher NLR group (≥3) and 13.3 months in the lower NLR group (<3) (p < 0.0001). There was no significant difference in the OS between the TKI and ICI therapies in the low NLR group (12.9 vs. 13.6 months, p = 0.411) or in the high NLR group (4.7 vs. 5.5 months, p = 0.32). Both univariate and multivariate analyses revealed that a higher NLR was an independent prognostic factor of long-term survival in patients with mRCC treated with first-line therapy. Conclusions: This retrospective study showed that adding NLR to other Memorial Sloan Kettering Cancer Center (MSKCC) and International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) variables might improve the prognostic and predictive power of these models.

Tumor-to-tumor metastasis (TTM) is a rare phenomenon documented in patients with multiple primary cancers. This condition is defined as a metastasis between two true primary tumors. The most frequently reported recipient tumor is renal cell carcinoma (RCC), and the lung carcinomas are the most common metastatic tumor donors. Therefore, this paper attempts to address the current gap in knowledge about this rare phenomenon. The first part of this review outlines the recently proposed models and mechanisms involved in the TTM process. The second part then summarizes and analyzes previous case reports in the literature. We also present our experience with the case of lung cancer that metastasized into RCC. Given the sporadic incidence of TTM, no specific management guidelines exist. Therefore, considering TTM in patients with multiple primary tumors is important as it could potentially modify the oncological management offered.

Introduction: Kidney transplant recipients present a higher risk of developing malignancies than the general population. Malignancies represent the third leading cause of death for kidney transplant recipients. There is an increased risk of developing urothelial carcinoma among kidney transplant recipients, but it is not as high as the risk of renal cell carcinoma, which is the most common urologic malignancy. Although the bladder is the most common location for urothelial carcinoma, urothelial carcinomas of the upper tracts of the native kidneys and the allograft are also reported. The estimated incidence of urothelial carcinomas arising on kidney grafts is 0.019%. Case report: We present a case of a kidney transplant recipient who developed non-muscle-invasive bladder cancer 10 years after the transplant. This was successfully treated with TURBT (transurethral resection of the bladder tumor) and BCG (bacillus Calmette–Guerin) instillations. Two years later, this patient developed metastatic urothelial carcinoma of the allograft. Discussion: Nephroureterectomy of the transplant with bladder preservation after BCG treatment, no systemic chemotherapy, and cessation of immunotherapy were the treatments of choice in this case. Local oncologic control and spontaneous complete regression of pulmonary metastasis were obtained at a 2-year follow-up. Conclusions: With this case, we emphasize the fact that managing urothelial carcinomas in kidney transplant recipients is a provocative challenge for surgeons, nephrologists, and oncologists, as there are no treatment guidelines or protocols.

Renal cell carcinoma (RCC) is the most prevalent solid organ malignancy among kidney transplant recipients, demonstrating substantially higher incidence rates compared to those in the general population. Although RCC is most commonly diagnosed in native kidneys, its development in transplanted kidneys has an infrequent occurrence. The use of immunosuppressive therapies, pre-existing chronic kidney disease and the unique anatomical characteristics of transplanted kidneys represent considerable therapeutic challenges in managing RCC within this patient cohort. Open radical transplantectomy plays a crucial role in curative treatment for localized RCC, whereas nephron-sparing surgery (NSS), in selected cases, can provide similar oncologic benefits while preserving allograft function. Recently, laparoscopic and robotic surgical procedures have demonstrated favorable outcomes as viable alternatives to conventional open surgery. Furthermore, ablative therapies like radiofrequency ablation and cryoablation can be considered therapeutic alternatives for small renal masses, offering the benefit of preserving allograft function, especially in high-risk surgical candidates. Limited data exist regarding the management of metastatic RCC in transplant recipients. Surgery, withdrawal of immunosuppression and systemic adjuvant therapy could be considered. Management of RCC in transplanted kidneys requires a multidisciplinary approach considering patient-specific characteristics, tumor features and the developing landscape of both surgical and non-surgical options. Further research is needed to refine therapeutic strategies in order to achieve optimal oncological outcomes while preserving allograft function.

Renal cell carcinoma (RCC) is the most common solid-organ malignancy in Western countries, and upper tract urothelial carcinoma (UTUC) is the most common malignancy in Asian countries. The management of RCC/UTUC in kidney transplant recipients is complex and clinically challenging due to post-transplant modifications associated with immunosuppressive treatment. This retrospective study evaluated the incidence, risk factors, treatment outcomes, and oncological implications of RCC and UTUC in kidney transplant recipients from 2008 to 2023. Data were collected from clinical records, and follow-up calls for 20 patients diagnosed with RCC and UTUC among 2,283 kidney transplant recipients, revealing an incidence rate of 0.78% for RCC (18 patients) and 0.087% (two patients) for UTUC. Most patients presented localized disease at diagnosis. Surgical interventions included radical nephrectomy for the native kidney’s RCC, radical or partial nephrectomy for allograft RCC, and radical nephroureterectomy for UTUC in the native kidney and allograft. Oncological outcomes indicated a mean follow-up of 51.29 months, during which five patients (25%) developed metastases, which achieved prolonged survival through surgical management, adjuvant therapy, and immunosuppression adjustments. The study highlights the increased cancer risk in this population and underscores the necessity for established screening protocols and individualized treatment strategies to optimize patient outcomes while preserving kidney function. These findings contribute to the ongoing research on managing malignancies in transplant recipients, with implications for further research and clinical guidelines.