Down-Grading of Ipsilateral Hydronephrosis by Neoadjuvant Chemotherapy Correlates with Favorable Oncological Outcomes in Patients Undergoing Radical Nephroureterectomy for Ureteral Carcinoma

Few studies have analyzed the details of neoadjuvant chemotherapy (NAC)-induced changes in patients with upper tract urothelial carcinoma. This study aimed to describe the impact of down-grading ipsilateral hydronephrosis by NAC for ureteral carcinoma. An observational study was conducted in 32 patients with cT1-3N0M0 ureteral carcinoma treated with NAC and radical nephroureterectomy. Hydronephrosis was classified into five grades based on computed tomography findings. We focused on the differences between the baseline and post-NAC status of ipsilateral hydronephrosis, radiographic tumor response, and blood markers. Down-grading, no change, and up-grading was observed in 10 (31%), 21 (66%), and 1 (3%) patients, respectively. In univariate analysis, locally advanced disease (cT3), severe hydronephrosis (grade 3/4) at baseline, no change/up-grading of hydronephrosis after NAC, and pathological lymphovascular involvement were identified as potential prognostic factors of progression-free and cancer-specific survival after radical nephroureterectomy. Locally advanced disease (cT3) at baseline and no change/up-grading of hydronephrosis by NAC were independently associated with poor progression-free survival. Notably, none of the patients with NAC-induced down-grading of hydronephrosis died of ureteral carcinoma during the follow-up. We reported the prognostic impact of down-grading of ipsilateral hydronephrosis, which could serve as a useful aid or clinical marker for decision-making.


Introduction
Upper tract urothelial carcinoma (UTUC) is a rare, heterogeneous, and aggressive malignancy with a poor prognosis [1]. Despite the significant advances made in surgical skill, diagnostic techniques, and Diagnostics 2020, 10, 10 2 of 14 identification of clinicopathological and biological prognostic factors, the clinical outcomes of UTUC have not significantly improved over the decades [1][2][3][4]. Recently, the results of a phase III randomized controlled trial of adjuvant chemotherapy (AC) vs. non-AC surveillance in pT2-4 N0-3 M0 UTUC (POUT study) have shown that AC prolonged progression-free survival after radical nephroureterectomy (RNU) [5]. Moreover, the trial was terminated early because the clinical efficacy outcomes favored the AC arm. Gregg et al. reported a systematic review and meta-analysis based on 13 comparative studies, and concluded that perioperative chemotherapy including AC and neoadjuvant chemotherapy (NAC) could provide a survival benefit after RNU [6]. However, the roles of perioperative systemic chemotherapy for UTUC and an optimized treatment sequence remain unclear because of the scarcity of evidence.
There are accumulating data suggesting that patients with high-risk UTUC should be considered for NAC in an attempt to administer a sufficient dose of cisplatin before RNU [7]. To date, NAC has not been widely accepted as a routine treatment strategy for locally advanced UTUC. This seems predominantly because clinicians consider that not all patients benefit from systemic chemotherapy and it can cause toxicities which can delay RNU. Several prognostic factors at baseline have been identified to support decision making in the pursuit of personalized care [8][9][10][11][12][13], including radiographic variables, inflammatory markers, nutritional indices, and molecular markers. Some studies analyzed the relationship of hydronephrosis at baseline to poor outcomes [10][11][12][13]. Cho et al. uniquely reported tumor-caused hydronephrosis grades ranging from one to four, and concluded that there is a positive association between hydronephrosis grade and advanced pathological finding and oncological outcomes [13].
Few studies have analyzed the details of NAC-induced changes such as down-grading of ipsilateral hydronephrosis and shrinkage of the ureteral tumor. In this study, to establish the role of perioperative chemotherapy, we investigated whether a positive response to NAC correlates with better outcomes after RNU.

Study Cohort and Data Collection
This multi-institutional study was approved by the research ethical committee of each participating institute (project code: 1258, date of approval: 20 August 2018). Informed consent was obtained for all human subjects. The study was conducted in compliance with the study's protocol and following the provisions of the Declaration of Helsinki (2013).
We retrospectively reviewed our cohort of 95 patients with non-metastatic UTUC treated with NAC and subsequent RNU between November 1995 and April 2018. The study cohort was restricted, as follows: (1) cT1-T3N0M0 ureteral carcinoma, (2) presence of tumor-induced ipsilateral hydronephrosis, (3) radiographic urinary tract evaluation of both pre-NAC and post-NAC status, and (4) sufficient clinicopathological data including follow-up information. The restriction left 32 patients (33.6%) who were eligible for the analysis (Figure 1).
The procedure of RNU and the postoperative follow-up protocol have been described in our previous report [1]. The patterns of recurrence sites of UTUC after RNU are diverse (urinary tract, lymph nodes, liver, bone, and lungs). Intravesical recurrence (IVR) after RNU was defined as an intravesical tumor that was pathologically confirmed as urothelial carcinoma. Extra-urinary recurrence, hereinafter referred to as "progression," was defined as local recurrence or distant metastasis to the lymph nodes, bone, or other visceral organs after RNU. The clinicopathological characteristics of the patients, including age, sex, laboratory data, tumor location, tumor diameter, estimated tumor volume, radiographic data, and pathological findings of the RNU specimen, were all obtained from the medical charts.

Preoperative Systemic Chemotherapy
The planned treatment usually involved 2-3 cycles of NAC and 2-3 cycles of AC with gemicitabine/cisplatin, methotrexate/vinblastine/Adriamycin/cisplatin, or other platinum-based regimens including carboplatin. AC usually started within 3 months after RNU. The detailed dose was described previously [1]. The regimen was selected by the attending clinician mostly based on renal function, comorbidities, and performance status.

Image Interpretation for Ureteral Tumor and Hydronephrosis
All computed tomography (CT) images taken before and after NAC were uploaded in a cloud medical imaging platform (Ambra Health, New York, NY, USA). The images were reevaluated and interpreted by a radiologist (N.M.) with special expertise in urogenital imaging. The investigator was blinded to any other clinicopathological variables. Tumor stage (according to the 2010 American Joint Committee on Cancer tumor-node-metastasis staging system), long diameter of the tumor, estimated tumor volume, and ipsilateral hydronephrosis were determined based on multiplanar reconstruction including axial, sagittal, and coronal CT images. Tumor response was evaluated by the response evaluation criteria in solid tumors (RECIST) v1.1 and estimated tumor volume. Tumor volumes (cm 3 ) were estimated using measurements of length × width × height × (π/6) [14]. Response was defined as post-NAC volume/pre-NAC volume × 100 and categorized into four groups, as follows: complete response (CR, 100% remission), partial response (PR, ≥30% remission), stable disease (<30% remission to >20% increase), and progressive disease (≥20% increase). Ipsilateral hydronephrosis was graded as 0-4 according to the previously reported classification [10,13]. We focused on the differences between pre-NAC and post-NAC status in terms of long diameter of the tumor, estimated tumor volume, and ipsilateral hydronephrosis.

Statistical Analysis
Progression-free survival (PFS), cancer-specific survival (CSS), and IVR-free survival were calculated from the date of RNU. Survival rates were analyzed using the Kaplan-Meier method and compared using the log-rank test for univariate analysis. Multivariate analyses were used to identify independent prognostic variables based on a stepwise Cox proportional hazard regression model and variables that potentially affected survival (p < 0.05 in univariate analysis). Data were analyzed using the SPSS software (version 21; IBM SPSS, Armonk, NY, USA) and plotted using the PRISM

Preoperative Systemic Chemotherapy
The planned treatment usually involved 2-3 cycles of NAC and 2-3 cycles of AC with gemicitabine/cisplatin, methotrexate/vinblastine/Adriamycin/cisplatin, or other platinum-based regimens including carboplatin. AC usually started within 3 months after RNU. The detailed dose was described previously [1]. The regimen was selected by the attending clinician mostly based on renal function, comorbidities, and performance status.

Image Interpretation for Ureteral Tumor and Hydronephrosis
All computed tomography (CT) images taken before and after NAC were uploaded in a cloud medical imaging platform (Ambra Health, New York, NY, USA). The images were reevaluated and interpreted by a radiologist (N.M.) with special expertise in urogenital imaging. The investigator was blinded to any other clinicopathological variables. Tumor stage (according to the 2010 American Joint Committee on Cancer tumor-node-metastasis staging system), long diameter of the tumor, estimated tumor volume, and ipsilateral hydronephrosis were determined based on multiplanar reconstruction including axial, sagittal, and coronal CT images. Tumor response was evaluated by the response evaluation criteria in solid tumors (RECIST) v1.1 and estimated tumor volume. Tumor volumes (cm 3 ) were estimated using measurements of length × width × height × (π/6) [14]. Response was defined as post-NAC volume/pre-NAC volume × 100 and categorized into four groups, as follows: complete response (CR, 100% remission), partial response (PR, ≥30% remission), stable disease (<30% remission to >20% increase), and progressive disease (≥20% increase). Ipsilateral hydronephrosis was graded as 0-4 according to the previously reported classification [10,13]. We focused on the differences between pre-NAC and post-NAC status in terms of long diameter of the tumor, estimated tumor volume, and ipsilateral hydronephrosis.

Statistical Analysis
Progression-free survival (PFS), cancer-specific survival (CSS), and IVR-free survival were calculated from the date of RNU. Survival rates were analyzed using the Kaplan-Meier method and compared using the log-rank test for univariate analysis. Multivariate analyses were used to identify independent prognostic variables based on a stepwise Cox proportional hazard regression model and variables that potentially affected survival (p < 0.05 in univariate analysis). Data were analyzed using the SPSS software (version 21; IBM SPSS, Armonk, NY, USA) and plotted using the PRISM software (version 7.00; GraphPad, San Diego, CA, USA). The statistical significance was set at p < 0.05, and all reported p values were two-sided.  Table 1 shows the clinicopathological characteristics and treatment options of 32 patients with ureteral carcinoma. More than half of the patients had locally advanced tumor (cT3). Four representative images of grade 1 to 4 hydronephrosis are shown in Figure 2A. Grades 1, 2, 3, and 4 were observed in 2 (6%), 8 (25%), 11 (34%), and 11 (34%) patients at baseline, respectively. The median follow-up period after RNU was 16 months. During the follow-up period, 14 patients (44%) and 12 patients (38%) experienced progression and IVR, respectively, and 11 patients (34%) died of ureter cancer. Further, we analyzed the association between the baseline hydronephrosis grade and oncological outcomes. Univariate analysis for progression, cancer-specific death, and IVR demonstrated that grade 3/4 hydronephrosis was associated with shorter PFS and CSS, but not with IVR-free survival ( Figure 2B-D). As expected, the renal function of patients with grade 3/4 hydronephrosis was significantly decreased compared with those with grade 1/2 hydronephrosis (mean ± standard deviation estimated glomerular filtration rate, 44 ± 11 vs. 57 ± 12 mL/min/1.73 m 2 ; Figure 3).

Clinical Impact of Change in Hydronephrosis Grade Induced by NAC
Post-NAC hydronephrosis was graded and compared with the pre-NAC (baseline) status. Representative images of down-graded hydronephrosis are shown in Figure 4A. Only 1 patient experienced up-grading from grade 2 to 3, whereas dramatic down-grading from grade 4 to 0 was observed in a 67-year-old male patient with cT3 left lower ureteral carcinoma (case 2 in Figure 4A). Of the 32 patients, 10 (31%), 21 (66%), and 1 (3%) showed down-grading, no change, and up-grading, respectively ( Figure 4B). The pathological examination of the surgical specimen after NAC showed Methotrexate, Vinblastine, Doxorubicin, and Cisplatin; † the 7th edition of the UICC-AJCC TNM staging system.

Clinical Impact of Change in Hydronephrosis Grade Induced by NAC
Post-NAC hydronephrosis was graded and compared with the pre-NAC (baseline) status. Representative images of down-graded hydronephrosis are shown in Figure 4A. Only 1 patient experienced up-grading from grade 2 to 3, whereas dramatic down-grading from grade 4 to 0 was observed in a 67-year-old male patient with cT3 left lower ureteral carcinoma (case 2 in Figure 4A). Of the 32 patients, 10 (31%), 21 (66%), and 1 (3%) showed down-grading, no change, and up-grading, respectively ( Figure 4B). The pathological examination of the surgical specimen after NAC showed

Clinical Impact of Change in Hydronephrosis Grade Induced by NAC
Post-NAC hydronephrosis was graded and compared with the pre-NAC (baseline) status. Representative images of down-graded hydronephrosis are shown in Figure 4A. Only 1 patient experienced up-grading from grade 2 to 3, whereas dramatic down-grading from grade 4 to 0 was observed in a 67-year-old male patient with cT3 left lower ureteral carcinoma (case 2 in Figure 4A). Of the 32 patients, 10 (31%), 21 (66%), and 1 (3%) showed down-grading, no change, and up-grading, respectively ( Figure 4B). The pathological examination of the surgical specimen after NAC showed no cancer cells in the ureter (pT0), and the patient has survived for 12 months without any disease recurrence and progression thus far. Univariate analysis demonstrated that down-grading of hydronephrosis Diagnostics 2020, 10, 10 6 of 14 was associated with better PFS and CSS, but not IVR-free survival ( Figure 4C-E). Table 2 shows the association between the baseline characteristics and change of hydronephrosis grade after NAC. There was a marginal association between low age and down-grading of hydronephrosis (p = 0.09). Moreover, we investigated the association between the number of NAC cycles and change in hydronephrosis grade. Four of nine patients (44%) treated with one cycle experienced down-grading, whereas around 25% of patients treated with two or three cycles experienced down-grading of ipsilateral hydronephrosis. There was no significant association between the number of NAC cycles and change in hydronephrosis grade (Table 3).
Diagnostics 2020, 10, x FOR PEER REVIEW 6 of 14 no cancer cells in the ureter (pT0), and the patient has survived for 12 months without any disease recurrence and progression thus far. Univariate analysis demonstrated that down-grading of hydronephrosis was associated with better PFS and CSS, but not IVR-free survival ( Figure 4C-E). Table 2 shows the association between the baseline characteristics and change of hydronephrosis grade after NAC. There was a marginal association between low age and down-grading of hydronephrosis (p = 0.09). Moreover, we investigated the association between the number of NAC cycles and change in hydronephrosis grade. Four of nine patients (44%) treated with one cycle experienced down-grading, whereas around 25% of patients treated with two or three cycles experienced down-grading of ipsilateral hydronephrosis. There was no significant association between the number of NAC cycles and change in hydronephrosis grade (Table 3).      Figure 5A shows the tumor diameters before and after NAC. The mean response rate was 42% remission, and more than 60% of patients obtained an objective response with respect to the ureteral tumor ( Figure 5B; CR in 18% and PR in 44%). There were no patients experiencing PD during NAC in our cohort. In contrast to the results of hydronephrosis, there was no significant association between tumor response and outcomes after RNU ( Figure 5C-E). Supplementary Figure S1 shows the analysis of the tumor response to NAC in estimated tumor volume. The results were similar to those of the RECIST criteria.

Prognostic Value of NAC-Induced Changes and Other Potential Factors
Additional analyses were performed to investigate the prognostic values of NAC-induced changes. The pre-NAC and post-NAC mean values of C-reactive protein in blood were 0.45 ± 1.26 and 0.23 ± 0.54 mg/L (p = 0.38), respectively, whereas those of the neutrophil-to-lymphocyte ratio were 3.3 ± 2.4 and 3.2 ± 1.9 (p = 0.06), respectively. In univariate analysis (Table 4), locally advanced disease (cT3), severe hydronephrosis (grade 3/4) at baseline, no change/up-grading of hydronephrosis after NAC, and pathological lymphovascular involvement in the RNU specimen were identified as potential prognostic factors of PFS and CSS after RNU. However, no factor tested in this study was associated with the IVR risk. Multivariate analysis revealed that locally advanced disease (cT3) at baseline and no change/up-grading of hydronephrosis after NAC were independently associated with poor PFS, whereas hydronephrosis at baseline and pathological lymphovascular involvement were not independent prognostic factors (Table 5). Notably, none of the patients with NAC-induced down-grading of hydronephrosis died of ureteral carcinoma during the follow-up ( Figure 4D).

Prognostic Value of NAC-Induced Changes and Other Potential Factors
Additional analyses were performed to investigate the prognostic values of NAC-induced changes. The pre-NAC and post-NAC mean values of C-reactive protein in blood were 0.45 ± 1.26 and 0.23 ± 0.54 mg/L (p = 0.38), respectively, whereas those of the neutrophil-to-lymphocyte ratio were 3.3 ± 2.4 and 3.2 ± 1.9 (p = 0.06), respectively. In univariate analysis (Table 4), locally advanced disease (cT3), severe hydronephrosis (grade 3/4) at baseline, no change/up-grading of hydronephrosis after NAC, and pathological lymphovascular involvement in the RNU specimen were identified as potential prognostic factors of PFS and CSS after RNU. However, no factor tested in this study was associated with the IVR risk. Multivariate analysis revealed that locally advanced disease (cT3) at baseline and no change/up-grading of hydronephrosis after NAC were independently associated with poor PFS, whereas hydronephrosis at baseline and pathological lymphovascular involvement were not independent prognostic factors (Table 5). Notably, none of the patients with NAC-induced down-grading of hydronephrosis died of ureteral carcinoma during the follow-up ( Figure 4D).

Discussion
The present study focused on NAC-induced changes in patients with ureteral cancer presenting with hydronephrosis before treatment. To our knowledge, this is the first report to address the association between the down-grading of ipsilateral hydronephrosis and survival outcomes. Previous studies have demonstrated a positive association between baseline hydronephrosis grade and poor outcomes [10,11,13]. The largest-scale study thus far with 401 patients with UTUC failed to show an association between preoperative hydronephrosis and survival [12]. Among the previous studies, only that by Cho et al. excluded patients with renal pelvic carcinoma from the analysis. It seems better to restrict the study cohort to only patients with ureteral carcinoma for analyzing tumor-induced hydronephrosis, because hydronephrosis could not be accurately evaluated and graded in patients with renal pelvic carcinoma. Asai et al. proposed a unique classification of hydronephrosis based on the renal excretion of 18F-flurodeoxyglucose (FDG) on FDG-positron emission tomography/CT [15]. Their results showed that hydronephrosis without FDG excretion, defined as "type 2 hydronephrosis," was associated with less decline in renal function after RNU and a higher risk of muscle-invasive disease (≥pT2). Therefore, hydronephrosis in UTUC, especially ureteral carcinoma, is believed to be informative and helpful for deciding the treatment strategy.
The potential benefit of NAC for UTUC is originally supported by the preceding clinical trials involving patients with muscle-invasive bladder cancer (MIBC), which provided robust evidence showing improved survival in patients who had NAC [16,17]. Poten et al. compared patients with high-risk UTUC who underwent NAC treatment followed by RNU and those who did not have NAC (matched historical cohort) to conclude that the NAC cohort had better survival in terms of five-year CSS (90% vs. 57%, p = 0.0015) [7]. Although there have been accumulating data showing good outcomes of NAC for UTUC, prospective randomized trials are needed to strongly recommend this treatment modality. Moreover, clinicians raised another clinical question about whether there are patients with the highest-risk non-metastatic UTUC requiring both NAC and AC. However, refined patient selection is needed for this highly invasive and long-standing treatment. Millikan et al. conducted a phase III trial evaluating the clinical potential of integrated therapy with radical cystectomy plus five cycles of M-VAC for high-risk MIBC [18]. Although the authors failed to find a preferred sequence (two cycles of NAC plus three cycles of AC vs. five cycles of AC), it is possible to select appropriate patients for such integrated therapy based on clinicopathological characteristics.
NAC consisting of multiagent regimens can cause substantial changes both in the primary tumor and the systemic condition of the patient. Some of these changes may serve as predictive markers for oncological outcomes. In a comprehensive review, Aziz et al. highlighted four retrospective studies evaluating the benefit of NAC for UTUC [19]. Of four studies, two [20,21] reported that the rates of NAC-induced pathological response were 13%-14% CR and 32%-40% PR. In our cohort, pathological CR (pT0) was observed similarly in four patients (13%). Two of four patients died of ureteral cancer during the follow-up. Neither pathological response nor radiographical response was a favorable prognostic factor in the present study. Among the tested NAC-induced changes, only down-grading of hydronephrosis was associated with better clinical outcomes (Table 4). It seems that down-grading of hydronephrosis requires a reduction in ureteral obstruction and the recovery of healthy peristaltic ureteral movement. Both observations may be crucial to achieving better survival benefit after RNU. Our findings suggested that the change in hydronephrosis grade induced by NAC for ureteral carcinoma would be a useful marker for selecting patients who need AC after RNU. To date, the optimal number of cycles of NAC for UTUC has not been determined. Down-grading of hydronephrosis may serve as a good indicator of the optimal number of cycles for each patient.
The present study has several limitations. First, it has a retrospective nature with potential selection bias. For example, some patients were excluded because of missing data. Second, a relatively small number of patients with UTUC-non-MIBC were enrolled in this analysis. Although UTUC is a rare tumor, our collaborative group has a database including more than 1500 patients. However, only a small percentage of patients with ureteral carcinoma underwent NAC treatment before RNU. This would be the common situation worldwide [1,22]. In addition, the studied cohort was from multiple institutions, which could introduce inconsistencies in surgical skills, selection of chemotherapy regimens, follow-up durations, clinical interpretations, and pathological diagnosis.

Conclusions
Some patients with high-risk UTUC should be managed using integrated multidisciplinary treatments including NAC, extirpative surgery, subsequent AC, immunotherapy, and radiotherapy. We believe that our findings could support clinical decision making. Further, large-scale retrospective observational studies and subsequent prospective trials are needed to better define the real clinical value of down-grading of ipsilateral hydronephrosis in terms of pathological and survival outcomes.