Outcomes of tyrosine kinase inhibitor monotherapy for advanced renal cell carcinoma arising in patients with kidney transplantation: comparison with sporadic and end-stage renal disease populations.

[BACKGROUND] Data regarding clinical outcomes of systemic therapy, including tyrosine kinase inhibitors (TKIs), for advanced renal cell carcinoma (RCC) after kidney transplantation (KTx) are limited.

[METHODS] We assessed clinical data of 13 patients with advanced RCC after KTx (KTx-RCC) who received first-line TKI monotherapy. Outcomes of the KTx-RCC group were compared with those of 275 patients with sporadic RCC and 37 patients receiving maintenance dialysis therapy for end-stage renal disease (ESRD) who received first-line TKIs.

[RESULTS] Overall survival (OS) was shorter in the KTx-RCC group than in the sporadic RCC group (p = 0.0007). However, multivariate analysis showed that the population type (i.e., KTx-RCC vs. sporadic RCC) was not an independent factor (p > 0.05). In contrast, other covariates such as non-clear cell histology (p = 0.0215), poor IMDC risk (p = 0.0304), and liver metastasis (p = 0.0016), which were frequently observed in the KTx-RCC group, were independent factors for shorter OS. Progression-free survival and OS were not significantly different between the KTx-RCC and ESRD-RCC groups (p > 0.05). Of the 13 patients in the KTx-RCC group, everolimus was administered to six patients (46%), but survival was not significantly different based on the administration (p > 0.05).

[CONCLUSIONS] The survival of patients with KTx-RCC after TKI monotherapy was shorter than that of patients with sporadic RCC, possibly due to the presence of multiple poor prognosticators. Effective treatment strategies, including postoperative monitoring for early diagnosis, should be identified in this high-risk population.