Renal Cell Carcinoma in Renal Transplantation: The Case for Surveillance

A retrospective single-center pilot study of the genetic background of the transplanted kidney

INTRODUCTION

Renal cell carcinoma (RCC) is one of the most prevalent cancers in kidney transplant recipients (KTR). The hereditary background of RCC in native kidneys has been determined, implicating its clinical importance.

MATERIALS AND METHODS

This retrospective single-center pilot study aimed to identify a potential genetic predisposition to RCC of the transplanted kidney and outcome in KTR who underwent single kidney transplantation between January 2000 and December 2020 and manifested RCC of the transplanted kidney. Next-generation sequencing (NGS) based germline genetic analysis from peripheral blood-derived genomic DNA (gDNA) was performed in both the recipient and donor using a gene panel targeting 226 cancer predisposition genes.

RESULTS

The calculated incidence of RCC of the transplanted kidney among 4146 KTR was 0.43%. In fifteen KTR and donors, NGS was performed. The mean KTR age at transplantation and the diagnosis of RCC was 50.3 years (median 54; 5-67 years) and 66 years (median 66; 24-79 years), respectively. The mean donor age at transplantation and graft age at RCC diagnosis was 39.7 years (median 42; 7-68 years) and 50.2 years (median 46; 20-83 years), respectively. The mean follow-up after RCC diagnosis was 47 months (median 39.1; 0-112 months). Papillary RCC was the most prevalent (n = 8), followed by clear cell RCC (n = 6) and unspecified RCC (n = 1). Thirteen RCCs were low-stage (pT1a/b) diseases, one was pT3, and one was of unknown stage. Most RCC was higher graded. No germline pathogenic cancer-predisposition variant was found in either KTR or donors except for several variants of uncertain significance.

CONCLUSION

RCC of the transplanted kidney is very rare. Germline cancer-predisposition testing has identified several variants of uncertain significance, but no germline genetic predisposition to graft RCC in KTR. Further research is needed to assess the clinical relevance of genetic testing for cancer risk in KTR.

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.

Incidental occurrence of papillary renal cell carcinoma in the native kidney with autosomal dominant polycystic kidney disease after renal transplantation: A case report

Autosomal dominant polycystic kidney disease (ADPKD) is one of the best-known genetic diseases. Almost half of the patients with ADPKD will develop end-stage renal disease, and the majority of patients are treated with renal transplantation. The current study presents a case that developed papillary renal cell carcinoma (PRCC) in the native right kidney 10 years after renal transplantation. PRCC is a not common malignant tumour entity (18.5% of all cases of renal cell carcinoma) compared with common clear cell renal carcinoma (65-70% of all cases of RCC).

Characteristics and Graft Survival of Kidney Transplant Recipients with Renal Cell Carcinoma

BACKGROUND

The incidence of renal cell carcinoma (RCC) is higher in kidney transplant recipients (KTRs) compared to the general population. However, the risk factors and outcomes based on the diagnosis of RCC after kidney transplantation are limited.

METHODS

We analyzed risk factors for the development of RCC in KTRs transplanted at our institution between 1994 and 2016. We compared the incidence of graft failure and mortality in KTRs with RCC to matched controls using 5:1 event density sampling. Identifying the risk factors of RCC and patient and graft survival were outcomes of interest.

RESULTS

There were 4,178 KTRs performed at our institution during the study period, and 51 patients were diagnosed with RCC. Recipients were followed until graft failure or death. We did not identify commonly looked at baseline characteristics associated with the risk of RCC. Comparing KTRs with RCC to matched controls, RCC patients were younger (47.5 vs. 49.6 years, p < 0.01), received basiliximab induction more commonly (p = 0.01), had hypertension and glomerulonephritis as causes of end-stage renal disease (p = 0.01), and were more likely to be smokers (p < 0.01). RCC was significantly associated with death-censored graft failure (adjusted hazard ratio [HR]: 1.76; 95% CI: 1.02-3.03; p = 0.04) but not patient death (adjusted HR: 0.95; 95% CI: 0.50-1.83; p = 0.89).

CONCLUSION

In our experience, RCC had a detrimental impact on graft survival among KTRs, highlighting the potential benefit of early diagnosis and optimal immunosuppression management in optimizing graft survival.

Incidence and Mortality of Renal Cell Carcinoma after Kidney Transplantation: A Meta-Analysis

BACKGROUND

The incidence and mortality of renal cell carcinoma (RCC) after kidney transplantation (KTx) remain unclear. This study's aims were (1) to investigate the pooled incidence/incidence trends, and (2) to assess the mortality/mortality trends in KTx patients with RCC.

METHODS

A literature search was conducted using the MEDLINE, EMBASE and Cochrane databases from inception through October 2018. Studies that reported the incidence or mortality of RCC among kidney transplant recipients were included. The pooled incidence and 95% CI were calculated using a random-effect model. The protocol for this meta-analysis is registered with PROSPERO; no. CRD42018108994.

RESULTS

A total of 22 observational studies with a total of 320,190 KTx patients were enrolled. Overall, the pooled estimated incidence of RCC after KTx was 0.7% (95% CI: 0.5-0.8%, I2 = 93%). While the pooled estimated incidence of de novo RCC in the native kidney was 0.7% (95% CI: 0.6-0.9%, I2 = 88%), the pooled estimated incidence of RCC in the allograft kidney was 0.2% (95% CI: 0.1-0.4%, I2 = 64%). The pooled estimated mortality rate in KTx recipients with RCC was 15.0% (95% CI: 7.4-28.1%, I2 = 80%) at a mean follow-up time of 42 months after RCC diagnosis. While meta-regression analysis showed a significant negative correlation between year of study and incidence of de novo RCC post-KTx (slopes = -0.05, P = 0.01), there were no significant correlations between the year of study and mortality of patients with RCC (P = 0.50). Egger's regression asymmetry test was performed and showed no publication bias in all analyses.

CONCLUSIONS

The overall estimated incidence of RCC after KTX was 0.7%. Although there has been a potential decrease in the incidence of RCC post-KTx, mortality in KTx patients with RCC has not decreased over time.