Treatment options and outcome for renal cell tumors in the transplanted kidney

Comparing surgical outcomes between robot-assisted laparoscopic and open partial nephrectomy for allograft kidney tumors: a retrospective, single-center study

BACKGROUND

Kidney transplantation is considered the best long-term option for patients with end-stage renal disease; however, immunosuppression increases the risk of developing malignancies. Approximately 0.2-0.5% of kidney transplant recipients experience renal cell carcinoma (RCC) in their allografts. Recently, nephron-sparing surgery has become widely accepted because of its favorable survival outcomes and low risk of recurrence.

METHODS

In this study, we retrospectively evaluated the peri- and postoperative outcomes of robot-assisted partial nephrectomy (RAPN) and open partial nephrectomy (OPN) for allograft RCC, analyzing five and six patients who underwent OPN and RAPN, respectively, from 1998 to 2023.

RESULTS

The estimated blood loss was significantly lower in the RAPN group than in the OPN group (6.5 mL [interquartile range (IQR): 1-15] vs. 350 mL [IQR: 139-560], P = 0.006), whereas the operative and renal arterial clamping times were similar. Additionally, the perioperative complication rate and severity were lower in the RAPN group, resulting in a significantly shorter postoperative hospital stay than the OPN group (3 days [IQR: 2-5] vs. 10 days [IQR: 8-12], P = 0.01). Postoperative renal function and oncological outcomes were similar between the two groups.

CONCLUSIONS

RAPN for allograft RCC demonstrated advantages in terms of estimated blood loss and postoperative hospital stay compared with OPN, even though the patients' backgrounds were not adjusted. Therefore, RAPN may be a viable option for managing T1 allograft tumors.

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.

Systematic review of ablative therapy for the treatment of renal allograft neoplasms

BACKGROUND

To date, there are no guidelines on the treatment of solid neoplasms in the transplanted kidney. Historically, allograft nephrectomy has been considered the only reasonable option. More recently, nephron-sparing surgery (NSS) and ablative therapy (AT) have been proposed as alternative procedures in selected cases.

AIM

To review outcomes of AT for the treatment of renal allograft tumours.

METHODS

We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 Checklist. PubMed was searched in March 2019 without time restrictions for all papers reporting on radiofrequency ablation (RFA), cryoablation (CA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE) of solid tumours of the kidney allograft. Only original manuscripts describing actual cases and edited in English were considered. All relevant articles were accessed in full text. Additional searches included all pertinent references. Selected studies were also assessed for methodological quality using a tool based on a modification of the Newcastle Ottawa scale. Data on recipient characteristics, transplant characteristics, disease characteristics, treatment protocols, and treatment outcomes were extracted and analysed. Given the nature and the quality of the studies available (mostly retrospective case reports and small retrospective uncontrolled case series), a descriptive summary was provided.

RESULTS

Twenty-eight relevant studies were selected describing a total of 100 AT procedures in 92 patients. Recipient age at diagnosis ranged from 21 to 71 years whereas time from transplant to diagnosis ranged from 0.1 to 312 mo. Most of the neoplasms were asymptomatic and diagnosed incidentally during imaging carried out for screening purposes or for other clinical reasons. Preferred diagnostic modality was Doppler-ultrasound scan followed by computed tomography scan, and magnetic resonance imaging. Main tumour types were: papillary renal cell carcinoma (RCC) and clear cell RCC. Maximal tumour diameter ranged from 5 to 55 mm. The vast majority of neoplasms were T1a N0 M0 with only 2 lesions staged T1b N0 M0. Neoplasms were managed by RFA (n = 78), CA (n = 15), MWA (n = 3), HIFU (n = 3), and IRE (n = 1). Overall, 3 episodes of primary treatment failure were reported. A single case of recurrence was identified. Follow-up ranged from 1 to 81 mo. No cancer-related deaths were observed. Complication rate was extremely low (mostly < 10%). Graft function remained stable in the majority of recipients. Due to the limited sample size, no clear benefit of a single procedure over the other ones could be demonstrated.

CONCLUSION

AT for renal allograft neoplasms represents a promising alternative to radical nephrectomy and NSS in carefully selected patients. Properly designed clinical trials are needed to validate this therapeutic approach.

Microwave Ablation of Renal Cell Carcinoma of the Transplanted Kidney: Two Cases

Thermal ablative techniques have been increasingly recognized as a valuable alternative to graftectomy and nephron-sparing surgery for the treatment of small neoplasms arising in the transplanted kidney. However, long-term efficacy and safety data are still lacking. In particular, current experience with microwave ablation is limited to a very recent single-centre series of three cases. We herein report two microwave ablations of renal cell carcinoma of the kidney allograft. The procedures were successfully performed under ultrasound guidance with complete tumour necrosis, no peri-operative complications, and preserved renal function. No recurrences were observed after 3 years of follow-up.

Transplant nephrectomy after graft failure: is it so risky? Impact on morbidity, mortality and alloimmunization

PURPOSE

To determine the impact of transplant nephrectomy on morbidity and mortality and HLA immunization.

METHODS

All patients who underwent transplant nephrectomy in our centre between 2000 and 2016 were included in this study. A total of 2822 renal transplantations and 180 transplant nephrectomies were performed during this period.

RESULTS

The indications for transplant nephrectomy were graft intolerance syndrome: 47.2%, sepsis: 22.2%, vascular thrombosis: 15.5%, tumour: 8.3% and other 6.8%. Transplant nephrectomies were performed via an intracapsular approach in 61.7% of cases. The blood transfusion rate was 50%, the morbidity rate was 38% and the mortality rate was 3%. Transplant nephrectomies more than 12 months after renal transplant failure were associated with more complications (p = 0.006). Transfusions in the context of transplant nephrectomy had no significant impact on alloimmunization.

CONCLUSION

The risk of bleeding, and therefore of transfusion, constitutes the major challenge of this surgery in patients eligible for retransplantation. Even if transfusions in this context of transplant nephrectomy had no significant impact on alloimmunization, this high-risk surgery, whenever possible, must be performed electively in a well-prepared patient.

Transplant nephrectomy

About 10% of all renal allografts fail during the first year of transplantation and thereafter approximately 3%-5% yearly. Given that approximately 69 400 renal transplants are performed worldwide annually, the number of patients returning to dialysis following allograft failure is increasing. A failed transplant kidney, whether maintained by low dose immunosuppression or not, elicits an inflammatory response and is associated with increased morbidity and mortality. The risk for transplant nephrectomy (TN) is increased in patients who experienced multiple acute rejections prior to graft failure, develop chronic graft intolerance, sepsis, vascular complications and early graft failure. TN for late graft failure is associated with greater morbidity and mortality, bleeding being the leading cause of morbidity and infection the main cause of mortality. TN appears to be beneficial for survival on dialysis but detrimental to the outcome of subsequent transplantation by virtue of increased level of antibodies to mismatched antigens, increased rate of primary non function and delayed graft function. Many of the studies are characterized by a retrospective and univariate analysis of small numbers of patients. The lack of randomization in many studies introduced a selection bias and conclusions drawn from such studies should be applied with caution. Pending a randomised controlled trial on the role of TN in the management of transplant failure patients, it is prudent to remove failed symptomatic allografts and all grafts failing within 3 mo of transplantation, monitor inflammatory markers in patients with retained failed allografts and remove the allograft in the event of a significant increase in levels.

De novo renal tumors arising in kidney transplants: midterm outcome after percutaneous thermal ablation

PURPOSE

To retrospectively evaluate the midterm outcome of patients treated for primary renal cell carcinomas arising in kidney transplants with minimally invasive techniques.

MATERIALS AND METHODS

The institutional review board of each participating institution approved this retrospective study and waived informed consent. This study was HIPAA compliant. A request for cases through the European Society of Urogenital Radiology network was made to institutions for patients who fit the requirements outlined by the authors, and a prospective follow-up of recipients was performed. Twenty-four tumors were identified that developed in the renal allograft of 20 patients from 11 institutions who were treated with radiofrequency ablation (n = 19) or cryoablation (n = 5) between 2003 and 2010. Maximal diameter of masses was 6-40 mm (median, 19.5 mm). Twenty masses were solid, and four were type 4 cystic masses. Preablation biopsy was performed for solid tumors only. All images and biologic and biopsy reports were retrospectively reviewed. Significant differences were determined by using a paired t test before and after ablation.

RESULTS

Mean follow-up was 27.9 months (range, 7-71 months). Histopathologic examination revealed papillary carcinoma in 17 patients and clear cell carcinoma in three. Tumors were successfully treated with ultrasonographic guidance in six patients, with computed tomographic guidance in 10 patients, and with both in four patients. One case of infection of the tumor site and one case of transitory genitofemoral nerve injury were the only reported complications. No significant change of renal function was noted. Subsequent imaging follow-up did not reveal any case of recurrence in the ablative site.

CONCLUSION

Percutaneous thermal ablation of renal tumors occurring in renal grafts is effective, with low morbidity. .