Nephron-sparing Surgery for Renal Cell Carcinoma of the Allograft After Renal Transplantation: Report of Two Cases

Management of renal cell carcinoma in transplant kidney: a systematic review and meta-analysis

INTRODUCTION

After transplantation, approximately 10% of renal cell carcinomas are detected in graft kidneys. These tumors (gRCC) present surgeons with the difficulty of finding a treatment that guarantees both oncological clearance and maintenance of function. We conducted a systematic review and an individual patient data meta-analysis on the oncology, safety and functional outcomes of the available treatments for gRCC.

EVIDENCE ACQUISITION

A systematic search was performed across MEDLINE, EMBASE, and Web of Science including any study reporting perioperative, functional and survival outcomes for patients undergoing graft nephrectomy (GN), partial nephrectomy (PN) or thermal ablation (TA) for gRCC. Quade's ANCOVA, Spearman Rho and Pearson χ², Kaplan-Meier, Log-rank and Standard Cox regression and other tests were used to compare treatments. Studies' quality was evaluated using a modified version of Newcastle Ottawa Scale.

EVIDENCE SYNTHESIS

A number of 29 studies (357 patients) were included. No differences between TA and PN were found in terms of safety, functional and oncological outcomes for T1a gRCCs. When applied to pT1b gRCC, PN showed no difference in complications, progression or cancer-specific deaths compared to smaller lesions; PN validity for pT2 gRCCs should be considered unverified due to lack of sufficient evidence. The efficacy and safety of PN or TA for multiple gRCC remain controversial. In case of non-functioning, large (T≥2), complicated or metastatic gRCCs, GN appears to be the most reasonable choice. Quality of evidence ranged from very low to moderate. Studies with large cohorts and longer follow-up are still needed to clarify oncological and functional differences.

CONCLUSIONS

PN and TA might be offered as a nephron-sparing treatment in patients with T1a gRCC. There is no significant difference between these options and GN in terms of oncological outcomes and complications. PN and TA offer similar functional outcomes and graft preservation. PN for T1b gRCC seems feasible and safe, but its validity should be considered unverified.

[Renal cell carcinoma of the kidney transplant: The French guidelines from CTAFU]

OBJECTIVE

To propose recommendations for the management of renal cell carcinomas (RCC) of the renal transplant.

METHOD

Following a systematic approach, a review of the literature (Medline) was conducted by the CTAFU to evaluate prevalence, diagnosis and management of RCC arousing in the renal transplant. References were assessed according to a predefined process to propose recommendations with levels of evidence.

RESULTS

Renal cell carcinomas of the renal transplant affect approximately 0.2% of recipients. Mostly asymptomatic, these tumors are mainly diagnosed on a routine imaging of the renal transplant. Predominant pathology is clear cell carcinomas but papillary carcinomas are more frequent than in general population (up to 40-50%). RCC of the renal transplant is often localized, of low stage and low grade. According to tumor characteristics and renal function, preferred treatment is radical (transplantectomy) or nephron sparing through partial nephrectomy (open or minimally invasive approach) or thermoablation after percutaneous biopsy. Although no robust data support a switch of immunosuppressive regimen, some authors suggest to favor the use of mTOR inhibitors. CTAFU does not recommend a mandatory waiting time after transplantectomy for RCC in candidates for a subsequent renal tranplantation when tumor stage<T3 and low ISUP grade.

CONCLUSION

These French recommendations should contribute to improving the oncological and functional prognosis of renal transplant recipients by improving the management of RCC of the renal transplant.

Treatment options for localised renal cell carcinoma of the transplanted kidney

Currently, there is no consensus among the transplant community about the treatment of renal cell carcinoma (RCC) of the transplanted kidney. Until recently, graftectomy was universally considered the golden standard, regardless of the characteristics of the neoplasm. Due to the encouraging results observed in native kidneys, conservative options such as nephron-sparing surgery (NSS) (enucleation and partial nephrectomy) and ablative therapy (radiofrequency ablation, cryoablation, microwave ablation, high-intensity focused ultrasound, and irreversible electroporation) have been progressively used in carefully selected recipients with early-stage allograft RCC. Available reports show excellent patient survival, optimal oncological outcome, and preserved renal function with acceptable complication rates. Nevertheless, the rarity and the heterogeneity of the disease, the number of options available, and the lack of long-term follow-up data do not allow to adequately define treatment-specific advantages and limitations. The role of active surveillance and immunosuppression management remain also debated. In order to offer a better insight into this difficult topic and to help clinicians choose the best therapy for their patients, we performed and extensive review of the literature. We focused on epidemiology, clinical presentation, diagnostic work up, staging strategies, tumour characteristics, treatment modalities, and follow-up protocols. Our research confirms that both NSS and focal ablation represent a valuable alternative to graftectomy for kidney transplant recipients with American Joint Committee on Cancer stage T1aN0M0 RCC. Data on T1bN0M0 lesions are scarce but suggest extra caution. Properly designed multi-centre prospective clinical trials are warranted.

Solid Renal Masses in Transplanted Allograft Kidneys: A Closer Look at the Epidemiology and Management

The objective of this review is to explore the available literature on solid renal masses (SRMs) in transplant allograft kidneys to better understand the epidemiology and management of these tumors. A literature review using PubMed was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. Fifty-six relevant studies were identified from 1988 to 2015. A total of 174 SRMs in 163 patients were identified, with a mean tumor size of 2.75 cm (range 0.5-9.0 cm). Tumor histology was available for 164 (94.3%) tumors: clear cell renal cell carcinoma (RCC; 45.7%), papillary RCC (42.1%), chromophobe RCC (3%), and others (9.1%). Tumors were managed by partial nephrectomy (67.5%), radical nephrectomy (19.4%), percutaneous radiofrequency ablation (10.4%), and percutaneous cryoablation (2.4%). Of the 131 patients (80.3%) who underwent nephron-sparing interventions, 10 (7.6%) returned to dialysis and eight (6.1%) developed tumor recurrence over a mean follow-up of 2.85 years. Of the 110 patients (67.5%) who underwent partial nephrectomy, 3.6% developed a local recurrence during a mean follow-up of 3.12 years. The current management of SRMs in allograft kidneys mirrors management in the nontransplant population, with notable findings including an increased rate of papillary RCC and similar recurrence rates after partial nephrectomy in the transplant population despite complex surgical anatomy.

Renal cell carcinoma in kidney allografts: histologic types, including biphasic papillary carcinoma

Kidney transplant recipients are at increased risk for malignancy, with about 5% incidence of cancer in native end-stage kidneys. Carcinoma in the renal allograft is far less common. Prior studies have demonstrated a propensity for renal cell carcinomas (RCCs) of papillary subtypes in end-stage kidneys, and perhaps in allograft kidneys, but most allograft studies lack detailed pathologic review and predate the current classification system. We reviewed our experience with renal carcinoma in kidney allografts at 2 academic centers applying the International Society of Urological Pathology classification, informed by immunohistochemistry. The incidence of renal allograft carcinoma was about 0.26% in our population. Of 12 allograft carcinomas, 6 were papillary (50%), 4 were clear cell (33%), 1 was clear cell (tubulo)papillary, and 1 chromophobe. Two of the papillary carcinomas had distinctive biphasic glomeruloid architecture matching the newly named "biphasic squamoid alveolar" pattern and were difficult to classify on core biopsies. The 2 cell types had different immunophenotypes in our hands (eosinophilic cells: RCC-/CK34betaE12+ weight keratin +/cyclin D1+; clear cells: RCC+/cytokeratin high molecular weight negative to weak/cyclin D1-). None of the patients experienced cancer recurrences or metastasis. Our study confirms the predilection for papillary RCCs in kidney allografts and highlights the occurrence of rare morphologic variants. Larger studies are needed with careful pathologic review, which has been lacking in the literature.

Renal cell carcinoma in functional renal graft: Toward ablative treatments

The occurrence of a kidney transplant tumor is a rare but serious issue with a double risk: the return to dialysis and the development of metastatic cancer. Publications on this topic are mainly case reports. The purpose of this review was to report an exhaustive literature review of functional graft renal cell carcinomas to highlight the impact of tumors on the renal graft outcomes. 201 de novo renal carcinomas in functional renal grafts from 69 publications were included. Incidence was estimated at 0.18%. Graft tumors were mostly asymptomatic (85.9%). Whatever the discovery circumstances of graft tumors, they were mostly documented by graft ultrasounds supplemented by CT-scanning or MR imaging. Nephron sparing surgery (95 patients) was the first treatment performed followed by radiofrequency ablation (38 patients) and cryotherapy (10 patients). The most common tumor graft histology was clear cell carcinoma (46.4%), followed by papillary carcinoma (43.7%). Specific mortality was 2.9% with 6 deaths. Renal graft cell carcinoma is a rare pathology with a low specific death. When possible, conservative treatment should be the first choice.

Nephron sparing surgery for De Novo kidney graft tumor: results from a multicenter national study

Nephron sparing surgery (NSS) results in the transplanted population remain unknown because they are only presented in small series or case reports. Our objective was to study renal sparing surgery for kidney graft renal cell carcinomas (RCC) in a multicenter cohort. Data were collected from 32 French transplantation centers. Cases of renal graft de novo tumors treated as RCC since the beginning of their transplantation activity were included. Seventy-nine allograft kidney de novo tumors were diagnosed. Forty-three patients (54.4%) underwent renal sparing surgery. Mean age of grafted kidneys at the time of diagnosis was 47.5 years old (26.1-72.6). The mean time between transplantation and tumor diagnosis was 142.6 months (12.2-300). Fifteen tumors were clear cell carcinomas (34.9%), and 25 (58.1%) were papillary carcinomas. Respectively, 10 (24.4%), 24 (58.3%) and 8 (19.5%) tumors were Fuhrman grade 1, 2 and 3. Nine patients had postoperative complications (20.9%) including four requiring surgery (Clavien IIIb). At the last follow-up, 41 patients had a functional kidney graft, without dialysis and no long-term complications. NSS is safe and appropriate for all small tumors of transplanted kidneys with good long-term functional and oncological outcomes, which prevent patients from returning to dialysis.

Tumor necrosis factor receptor 2: its contribution to acute cellular rejection and clear cell renal carcinoma

Tumor necrosis factor receptor 2 (TNFR2) is a type I transmembrane glycoprotein and one of the two receptors that orchestrate the complex biological functions of tumor necrosis factor (TNF, also designed TNF-α). Accumulating experimental evidence suggests that TNFR2 plays an important role in renal disorders associated with acute cellular rejection and clear cell renal carcinoma but its exact role in these settings is still not completely understood. This papers reviews the factors that may mediate TNFR2 induction in acute cellular rejection and clear cell renal carcinoma and its contribution to these conditions and discusses its therapeutic implications. A greater understanding of the function of TNFR2 may lead to the development of new anti-TNF drugs.