Renal cell carcinoma in kidney transplant recipients: descriptive analysis and overview of a major German transplant center

Renal cell carcinoma in kidney transplant recipients: incidence, trends, clinical management & outcomes

OBJECTIVE

To describe the incidence, characteristics, clinical management, and outcomes of renal cell carcinoma (RCC) among a large, single-centre cohort of kidney transplant recipients (KTR).

METHODS

We conducted an observational cohort study looking at KTR transplanted between January 2000-December 2017 (n = 2443) with ≥ 1 year of follow-up. Simultaneous kidney/pancreas transplants were excluded. The Kaplan-Meier product-limit method was used to determine the incidence of RCC. Characteristics and management of RCC were examined using descriptive statistics. Risk factors and clinical outcomes were analyzed using Cox regression models.

RESULTS

The incidence of RCC among our cohort was 0.32 per 100 person-years, 2.1% of all KTRs. Almost half (47.1%) of cases occurred within 4 years post-transplant. The majority of cases were T1a (86.3%), clear-cell (45.1%), and in the native kidney (80.4%). KTR diagnosed with RCC had a twofold higher incidence of other malignancies versus KTR without RCC. Overall mortality, but not cancer-specific mortality, at 2- and 5-years post-transplant was threefold higher among KTR with RCC than those without.

CONCLUSIONS

Incidence of RCC among our KTR was slightly higher than the general population; majority of cases occur in the native kidneys and are low stage, low grade. Indolent histologic variants were more common than the general population. KTR with RCC had a higher incidence of other malignancies. Overall, but not cancer-specific, mortality was higher among KTRs diagnosed with RCC.

Investigation of Underlying Biological Association and Targets between Rejection of Renal Transplant and Renal Cancer

Background

Post-renal transplant patients have a high likelihood of developing renal cancer. However, the underlying biological mechanisms behind the development of renal cancer in post-kidney transplant patients remain to be elucidated. Therefore, this study aimed to investigate the underlying biological mechanism behind the development of renal cell carcinoma in post-renal transplant patients.

Methods

Next-generation sequencing data and corresponding clinical information of patients with clear cell renal cell carcinoma (ccRCC) were obtained from The Cancer Genome Atlas Program (TCGA) database. The microarray data of kidney transplant patients with or without rejection response was obtained from the Gene Expression Omnibus (GEO) database. In addition, statistical analysis was conducted in R software.

Results

We identified 55 upregulated genes in the transplant patients with rejection from the GEO datasets (GSE48581, GSE36059, and GSE98320). Furthermore, we conducted bioinformatics analyses, which showed that all of these genes were upregulated in ccRCC tissue. Moreover, a prognosis model was constructed based on four rejection-related genes, including PLAC8, CSTA, AIM2, and LYZ. The prognosis model showed excellent performance in prognosis prediction in a ccRCC cohort. In addition, the machine learning algorithms identified 19 rejection-related genes, including PLAC8, involved in ccRCC occurrence. Finally, the PLAC8 was selected for further research, including its clinical and biological role.

Conclusion

In all, our study provides novel insight into the transition from the rejection of renal transplant to renal cancer. Meanwhile, PLAC8 could be a potential biomarker for ccRCC diagnosis and prognosis in post-kidney transplant patients.

Updated National Study of Functional Graft Renal Cell Carcinomas: Are They a Different Entity?

OBJECTIVE

To analyze de novo graft carcinoma characteristics from our updated national multicentric retrospective cohort.

METHODS

Thirty-two transplant centers have retrospectively completed the database. This database concerns all kidney graft tumors including urothelial, and others type but excludes renal lymphomas over 31 years.

RESULTS

One hundred and fifty twokidney graft carcinomas were diagnosed in functional grafts. Among them 130 tumors were Renal Cell Carcinomas. The calculated incidence was 0.18%. Median age of the allograft at diagnosis was 45.4 years old. The median time between transplantation and diagnosis was 147.1 months. 60 tumors were papillary carcinomas and 64 were clear cell carcinomas. Median tumor size was 25 mm. 18, 64, 21 and 1 tumors were respectively Fuhrman grade 1, 2, 3 and 4. Nephron sparing surgery (NSS) was performed on 68 (52.3%) recipients. Ablative therapy was performed in 23 cases (17.7%). Specific survival rate was 96.8%.

CONCLUSION

This study confirmed that renal graft carcinomas are a different entity: with a younger age of diagnosis; a lower stage at diagnosis; a higher incidence of papillary subtypes.

Renal Cell Carcinoma and Kidney Transplantation: A Narrative Review

Kidney transplant recipients (KTRs) are at increased risk of developing renal cell carcinoma (RCC). The cancer can be encountered at different steps in the transplant process. RCC found during work-up of a transplant candidate needs treatment and to limit the risk of recurrence usually a mandatory observation period before transplantation is recommended. An observation period may be omitted for candidates with incidentally discovered and excised small RCCs (<3 cm). Likewise, RCC in the donor organ may not always preclude usage if tumor is small (<2 to 4 cm) and removed with clear margins before transplantation. After transplantation, 90% of RCCs are detected in the native kidneys, particularly if acquired cystic kidney disease has developed during prolonged dialysis. Screening for RCC after transplantation has not been found cost-effective. Treatment of RCC in KTRs poses challenges with adjustments of immunosuppression and oncologic treatments. For localized RCC, excision or nephrectomy is often curative. For metastatic RCC, recent landmark trials in the nontransplanted population demonstrate that immunotherapy combinations improve survival. Dedicated trials in KTRs are lacking. Case series on immune checkpoint inhibitors in solid organ recipients with a range of cancer types indicate partial or complete tumor response in approximately one-third of the patients at the cost of rejection developing in ~40%.

Donor-Derived Renal Cell Carcinoma in a Kidney Allograft: A Case Report

Renal cell carcinoma (RCC) in the kidney allograft is a relatively rare complication most commonly seen approximately a decade or more after transplant. We report a case of diffuse multifocal RCC within 6 months of transplant. The initial signal leading to an abnormality in the graft was an elevated routine cell-free DNA. Initial imaging findings appeared consistent with post-transplant lymphoproliferative disorder; however, biopsy would ultimately yield RCC. The patient's diffuse disease necessitated radical nephrectomy. Tumor DNA fingerprinting was employed in this case to show the tumor originated from donor tissue rather than host, indicating primary rather than metastatic disease. Early RCC is a rare complication. Most cases are detected at an early stage, likely as a result of increased surveillance with ultrasound imaging. A donor's social history including significant tobacco use should be considered when evaluating the risk of malignancy transmission in the allograft. Clinicians should be aware of multifocal RCC as a potential differential diagnosis for diffuse nodular infiltrates in the allograft.