Oncologic outcomes comparison of partial ureterectomy and radical nephroureterectomy for urothelial carcinoma

Upper tract urothelial carcinomas (UTUCs), as a kind of urothelial carcinomas (UCs), accounting for only 5–10% [1]. Generally, 60% of UTUCs are invasive [2]. Seventy to Ninety years old showed the highest morbid risk among all age groups and are three times more ordinary in men [2]. UTUC with pure nonurothelial histology is quite rare, but about 25% of cases have variants. Computed tomography (CT) is an available imaging technique with high diagnostic accuracy [3]. In about 90% of cases, the tumor grade can be determined with a low false negative rate [4]. Ureteroscopic biopsy combining with urinary cytology, and imaging findings such as hydronephrosis may contribute for the decision of surgical type like partial ureterectomy (PU) and radical nephroureterectomy (RNU) [5]. Tumor stage and grade, lymph node involvement, lymphovascular invasion, surgical margins, and pathological factors could be used to estimate prognosis [2]. Nowadays, the concept for preservation of renal function has been emphasized. For low-risk UTUC, kidney-sparing surgery (KSS) unlike radical surgery could preserve kidney function without compromising oncological outcomes. KSS such as PU are performed for the patients with solitary kidney, renal insufficiency, or low-risk tumors. RNU is still the standard treatment for high-risk UTUCs, no matter where the tumor location is [2, 6]. Herein, we used data in our database to assess the oncological outcomes between PU and RNU.

UTUC is a kind of rare malignancy. The main treatments for URUC are RNU and KSS like PU. Recent data indicated that patients with low grade UTUC could be treated by PU effectively. The guidelines of the European Association of Urology suggested that PU is a legitimate therapy for small, unifocal, low grade UTUC with no signs of infiltration [2, 7, 9], and indicated that RNU is still the standard treatment for high-risk UTUCs [2, 10]. However, Bagrodia et al. compared the prognosis of UTUC patients who suffered either RNU or PU. They suggested that PU seemed to possess oncologic efficacy equal to RNU. Meanwhile, PU could preserve the renal function to the maximum extent [9]. Similar results were also demonstrated in the investigation from Fukushima et al. [11]. Colin et al. conducted a multicenter cohort study of UTUC which suggested that surgical interventions was not the independent prognostic factor for recurrence-free survival (RFS) and CSS [6]. The investigation from Hung et al. indicated that the local recurrences, bladder recurrences, distant metastasis, and CSS showed no significant differences between RNU and PU [12]. These findings mentioned above would show the ability of PU to maximize the preservation of renal function in carefully selected patients.

In the current study, we noticed that pathological stage remained the most important predictor for the CSS of patients with UTUCs. The results also revealed that CSS showed no significant differences between RNU and PU in both low pT stage (pTa–1) and high pT stage (pT2–4) UTUCs. The probable reason is that the number of patients involved in our study is not large enough, thus this study may not be powerful enough to show significance [6]. Furthermore, there were some selection biases that RNU group seemed to have more aggressive pathological features compared with PU group, because there was not the standardized indication for PU and surgeon preferred PU for lower stage UTUCs [13, 14]. Selection biases can lead to better survival in PU group compared with RNU group, though the difference was not significant in our analysis. Our findings, and similar findings from other researchers, indicated that PU could act as a selectable treatment for selected UTUC patients [15]. In addition, pathologists with expertise rechecked all the pathologic specimens, and all pathologic results were collected standardly.

This study is retrospective study, and the number of involved patients is relatively small. These two characteristics are the main limitations of this study. Because a prospective randomized controlled study of PU compared with RNU is difficult due to the rarity of UTUC. Secondly, we could not ascertain whether PU was done imperatively or electively. Furthermore, surgeon preferences have a great impact on the surgical technique and indication for RNU and PU, which could not be determined standardly. Nor can we assess which cases are suitable for endoscopic treatment when receiving RNU therapy [16, 17].. Multiple surgeons were employed to operate on the investigated patients. This situation might lead to a selection bias and variable surgical techniques. Finally, another limitation of our research is that we could not provide the information about tumor grade and metastases due to the sample problem.

In conclusion, PU and RNU might possess equivalent long-term oncologic outcomes. Furthermore, PU could reduce the adverse outcomes of nephron loss caused by RNU. PU could be rational selection for selected patients with UTUCs. Further randomized researches compared with PU and RNU are still necessary to support the results. Prospective trials with large sample sizes are essential to more accurately assess the role of PU in UTUC.