Patient demographics and clinical characteristics

As shown in Table 1, the average time from KT to diagnosis of de novo UC was 98.1 ± 66.4 months. Of the 97 recipients of a renal transplant who were diagnosed with de novo UC, 77 (79.4%) were female and 20 (20.6%) were male. Among them, 82 (84.5%) received hemodialysis before KT (mean duration 12.8 ± 16.7 months), 65 (81.3%) had a confirmed history of exposure to AA, and 51 (52.6%) were diagnosed with upper urinary tract carcinoma (UTUC), 17 (17.5%) with bladder carcinoma (BC), and 29 (29.9%) with both UTUC and BC. The p values for the different groups are shown in Table 2.

Table 1 The characteristic of all cases Table 2 The survival time in each part and T stage BCStage ≤ T1

A total of 14 patients were diagnosed with stage ≤ T1 BC and underwent TURBT. One patient received bilateral nephroureterectomy and cystectomy after TURBT. Table 3 shows the OS, RFS, and PFS rates of these patients. The 5-year OS rate was 100%. Of the 14 patients, 8 (57.1%) received bladder infusion chemotherapy, and one received it for BC recurrence. The OS rates of the two groups were 100%, and there was no significant difference in RFS and PFS rates between them (p = 0.071 and 0.400, respectively). In total, 7 (50.0%) patients were treated with cyclosporine A (CsA) and 6 (42.9%) with tacrolimus (TAC), and there were no significant differences in OS, RFS, and PFS rates between the CsA and TAC groups (p = 0.281, 0.755, and 0.937, respectively).

Table 3 The P value in different group Stage ≥ T2

Only three patients were diagnosed with stage ≥ T2 BC. Two patients with stage T2 BC received TURBT, and one with stage T3 BC underwent partial cystectomy without infusion or GC/GCa chemotherapy. Of the two patients with stage T2 BC, one received infusion chemotherapy, and the other received GC/GCa chemotherapy. Two patients died after OS durations of 122 and 142 months, while the third was still alive after 48 months. All patients experienced disease recurrence with RFS durations of 40, 3, and 18 months, respectively. All patients developed metastasis to the upper urinary tract with PFS durations of 82, 9, and 23 months, respectively.

UTUCStage ≤ T1

A total of 27 patients diagnosed with stage ≤ T1 UTUC underwent nephroureterectomy without receiving GC/GCa chemotherapy. Table 3 shows their OS and PFS rates. The 5-year OS rate for these patients was 88.2%. After the initial diagnosis, 5 patients (18.5%) and 4 (14.8%) after recurrence had their immunosuppression regimen changed to rapamycin (RAP), while 18 (66.7%) did not receive RAP. There was no significant difference in OS and PFS rates between these patients (p = 0.057, 0.122). Of these patients, 19 (70.4%) were treated with CsA and 6 (22.2%) with TAC, with PFS being significantly longer in the CsA group than in the TAC group (p = 0.017) (Fig. 1A). However, there was no significant difference in OS rates between the two groups (p = 0.184). Among these 27 patients, 8 (29.6%) received infusion chemotherapy for BC after the initial diagnosis, 2 (7.4%) after recurrence, and 17 (63.0%) did not receive infusion chemotherapy, with no significant difference in clinical prognosis observed between the groups (p = 0.343 and 0.199) for OS and PFS, respectively.

Fig. 1

The survival of the patients in different group

A.The PFS time between CsA group and Tac group in T1 and lower stage of UTUC;

B. The PFS time between Rap group and control group in T2 and higher stage of UTUC;

C. The OS time between different sites in T1 and lower stage;

D. The RFS time between different sites in T1 and lower stage;

E. The OS time between different sites in T2 and higher stage

Stage ≥ T2

A total of 24 patients with stage ≥ T2 UTUC underwent nephroureterectomy. Table 3 shows the OS and PFS rates of these patients. The 5-year OS rate was 90.2%. Out of the 24 patients, 5 (20.8%) received GC/GCa chemotherapy while 19 (79.2%) did not. There was no significant difference in the OS and PFS rates between the two groups (p = 0.132 and 0.521, respectively). The immunosuppression regimen was changed to RAP for 4 (16.7%) patients after the initial diagnosis, but there was no significant difference in OS between patients treated with and without RAP (p = 0.317). PFS was superior in the RAP group compared to the control group (p = 0.026) (Fig. 1B).

UTUC combined with BCStage ≤ T1

A total of 14 patients diagnosed with stage ≤ T1 UTUC + BC underwent nephroureterectomy, TURBT or partial cystectomy, with only one patient receiving GC/GCa chemotherapy. Table 3 shows the OS, RFS, and PFS rates of these patients, with a 5-year OS rate of 57.7%. The immunosuppression regimen was changed to RAP for 2 (14.3%) patients after the initial diagnosis and 1 (7.1%) after recurrence, while 11 (78.5%) did not receive RAP. No significant differences in clinical prognosis were found between patients treated with or without RAP (p = 0.225, 0.980, and 0.274, respectively). Bladder infusion chemotherapy was administered to 10 (71.4%) patients after the initial diagnosis and 1 (7.1%) after recurrence, while 3 (21.4%) did not receive infusion chemotherapy. No significant differences in clinical prognosis were found among these three groups (p = 0.665, 0.778, and 0.288, respectively). However, there was no significant difference in OS, RFS, and PFS rates between 10 (71.4%) patients treated with CsA and 2 (14.3%) treated with TAC (p = 0.672, 0.361, and 0.895, respectively).

Stage ≥ T2

A total of 15 patients diagnosed with stage ≥ T2 UTUC + BC underwent nephroureterectomy, TURBT, partial cystectomy, or cystectomy, with a 5-year OS rate of 48.2%. Only 3 (20.0%) patients had their immunosuppression regimen changed to RAP, and there was no significant difference in OS, RFS, and PFS rates between patients treated with or without RAP (p = 0.602, 0.362, and 0.436, respectively). Of the 15 patients, only 6 (40.0%) received bladder infusion chemotherapy, and no differences in OS, RFS, and PFS rates were found between the two groups (p = 0.284, 0.697, and 0.825, respectively). No significant differences in OS, RFS, and PFS rates were found between 4 (26.7%) patients who received GC/GCa chemotherapy and 11 who did not (p = 0.507, 0.885, and 0.436, respectively).

Prognosis according to site and T stageSite

Patients were classified into the BC, UTUC, or UTUC + BC group based on the primary tumor site. For stage ≤ T1 disease, there were significant differences in OS and RFS among the three groups (p = 0.045 and 0.001, respectively) (Fig. 1C and D). OS was significantly reduced in the UTUC + BC group compared to the BC and UTUC groups, while the UTUC group had the longest RFS and the BC group had the shortest. Meanwhile, there were no significant differences in PFS among the three groups (p = 0.183). For stage ≥ T2, there was a significant difference in OS among the three groups (p = 0.017) (Fig. 1E). OS was comparatively shorter in the UTUC + BC group than in the UTUC group. Notably, there were no significant differences in RFS and PFS among the three groups (p = 0.180 and 0.078, respectively).

T stage

Comparisons of patient prognosis based on T stage revealed no significant difference in survival.