Long-term outcome of kidney transplant by using restored kidney grafts after tumour ex vivo excision - a prospective study

Kidney Transplantation From Donors With Malignant Renal Masses: A Systematic Review

BACKGROUND

Small malignant renal tumors can be found in up to 1.3% of kidney donors. Several studies have investigated the use of these kidneys for transplantation, after ex vivo resection of the malignant mass.

METHODS

We performed a systematic review of the literature on PubMed, Embase, and Web of Science of studies including reports of malignant renal masses excised from kidney grafts prior to transplantation. Articles including benign pathology only were excluded.

RESULTS

Our search strategy identified 226 patients over 32 studies. Pathology included 107 clear cell carcinomas, 27 papillary renal cell carcinomas (RCCs), 84 other types of RCCs, and 8 transitional cell carcinomas. The majority of cancers were grade 1 or 2 (81.6%). Average tumor size was 12.6 mm. Clavien-Dindo ≥ 3 complication rate was 22%. Mean follow-up was 39.9 months. The 1-year, 3-year, and 5-year overall survival rate for recipients of living donor grafts was 95.8%, 92.1%, and 75.1%. The 1-year, 3-year, and 5-year living donor death-censored graft survival rate was 90.8, 85.2%, and 64.8%. Of the 226 patients, 6 (2.7%) experienced a malignant recurrence. The average time to recurrence was 36.1 months.

CONCLUSIONS

Transplantation of kidney grafts after resection of small cancerous masses is relatively safe and has low rates of recurrent malignancy. In the case of a living donor, appropriate counseling on partial nephrectomy versus donor nephrectomy should be provided, ideally by a surgeon who is not part of the transplant team. Recipients of these grafts should be carefully selected and counseled regarding the additional potential technical and oncological risks.

Optimizing the kidney donor pool: transplanting donor kidneys after partial nephrectomy of masses or cysts

Background

A limiting factor in expanding the kidney donor pool is donor kidneys with renal tumors or cysts. Partial nephrectomy (PN) to remove these lesions prior to transplantation may help optimize organ usage without recurrence of malignancy or increased risk of complications.

Methods

We retrospectively analyzed all recipients of a living or deceased donor graft between February 2009 and October 2022 in which a PN was performed prior to transplant due to the presence of one or more concerning growths. Donor and recipient demographics, perioperative data, donor allograft pathology, and recipient outcomes were obtained.

Results

Thirty-six recipients received a graft in which a PN was performed to remove suspicious masses or cysts prior to transplant. Majority of pathologies turned out to be a simple renal cyst (65%), followed by renal cell carcinoma (15%), benign multilocular cystic renal neoplasm (7.5%), angiomyolipoma (5%), benign renal tissue (5%), and papillary adenoma (2.5%). No renal malignancy recurrences were observed during the study period (median follow-up: 67.2 months). Fourteen complications occurred among 11 patients (30.6% overall) during the first 6mo post-transplant. Mean eGFR (± standard error) at 36 months post-transplant was 51.9 ± 4.2 ml/min/1.73 m2 (N = 23). Three death-censored graft losses and four deaths with a functioning graft and were observed.

Conclusion

PN of renal grafts with suspicious looking masses or cysts is a safe option to optimize organ usage and decrease the kidney non-use rate, with no observed recurrence of malignancy or increased risk of complications.

Renal Cell Carcinoma in End-Stage Kidney Disease and the Role of Transplantation

Kidney transplant patients have a higher risk of renal cell carcinoma (RCC) compared to non-transplanted end-stage kidney disease (ESKD) patients. This increased risk has largely been associated with the use of immunosuppression; however, recent genetic research highlights the significance of tissue specificity in cancer driver genes. The implication of tissue specificity becomes more obscure when addressing transplant patients, as two distinct metabolic environments are present within one individual. The oncogenic potential of donor renal tissue is largely unknown but assumed to pose minimal risk to the kidney transplant recipient (KTR). Our review challenges this notion by examining how donor and recipient microenvironments impact a transplant recipient's associated risk of renal cell carcinoma. In doing so, we attempt to encapsulate how ESKD-RCC and KTR-RCC differ in their incidence, pathogenesis, outcome, and approach to management.

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%.