A national study of kidney graft tumor treatments: Toward ablative therapy.

BACKGROUND: Results of the conservative treatment of renal cell carcinomas arising in functional renal transplants are unknown compared to transplant nephrectomy. Only small series or case reports have been reported.

METHODS: Data were collected from 32 transplantation centers nationwide on cases of de novo tumors in functional renal transplants presumed to be malignant between January 1988 and December 2013.

RESULTS: Among 116 de novo transplant tumors, 62 were treated conservatively including: 48 by partial nephrectomy (PN) and 14 by thermal ablation (TA). These patients were compared to 30 other patients who were treated by transplant nephrectomy. The median age of the transplanted kidneys at the time of diagnosis was 43.5 years old as calculated from the donor's age. Tumors treated by transplant nephrectomy presented more often with symptoms (pain, fever, impaired condition, hematuria) than tumors treated conservatively (P = .019). After PN, final histology showed 27 (47.5%) papillary carcinomas, 19 (32.2%) clear cell carcinomas, 1 mixed carcinoma, and 2 oncocytomas. The median tumor size treated by PN was 24 mm with no difference in comparison to the TA group. Nine patients treated by PN had postoperative complications (21%), including 4 requiring operative intervention (Clavien IIIb). None of the patients treated by TA had complications. Specific survival was 100% at the time of last follow-up (median time after treatment 37 months) for patients treated by PN or TA.

CONCLUSION: PN proved to be efficient in the treatment of small tumors of transplanted kidneys with good long-term functional and oncologic outcomes, including avoiding return to dialysis. TA seems to be an alternative therapy with good results in selected patients.