Tumor budding, defined as a single cancer cell or clusters of fewer than five cancer cells observed at the tumor invasion front, has been reported to be associated with poor prognosis in various types of cancers. However, limited information regarding the pathological and prognostic significance of tumor budding in upper urinary tract urothelial carcinoma (UUTUC) is available. We investigated 135 consecutive patients with newly diagnosed invasive UUTUCs (73 with renal pelvic cancers and 62 with ureteral cancers) treated with nephroureterectomy or partial ureterectomy between 1999 and 2018 in our hospital. Under a × 200 magnification, tumors with 10 or more budding foci were defined as “high tumor budding”. The median follow-up period was 53.6 months. Among the 135 patients, 41 (30%; 16 with renal pelvic cancers and 25 with ureteral cancers) showed high tumor budding. High tumor budding was related to adjuvant chemotherapy status, higher pathological T stage, lymphovascular invasion, lymph node metastasis, tumor location, concomitant variant histology, and non-papillary gross finding. The multivariate Cox analysis revealed that LVI and high tumor budding were independent predictors for extraurothelial recurrence (P = 0.039 and 0.014, hazard ratio = 2.50 and 2.88, respectively), and high tumor budding was an independent predictor for overall survival (P = 0.024, hazard ratio = 2.33). Tumor budding can be easily introduced in clinical practice with no need for immunohistochemical analysis, may be an important clinicopathological factor of UUTUC, and is suggested to be useful as a novel predictive prognostic factor of patients with invasive UUTUC.

肿瘤出芽，定义为在肿瘤侵袭前沿观察到的单个癌细胞或少于五个癌细胞的簇，据报道与各种类型的癌症预后不良有关。然而，关于上尿路尿路上皮癌 (UUTUC) 中肿瘤出芽的病理和预后意义的信息有限。我们调查了 1999 年至 2018 年间在我院接受肾输尿管切除术或输尿管部分切除术治疗的 135 例新诊断浸润性 UUTUC 患者（73 例肾盂癌和 62 例输尿管癌）。在 200 倍放大倍数下，具有 10 个或更多出芽病灶的肿瘤被定义为“高肿瘤出芽”。中位随访期为 53.6 个月。在 135 名患者中，41 名（30%；16 例肾盂癌和 25 例输尿管癌）显示出高肿瘤出芽。高肿瘤出芽与辅助化疗状态、较高的病理 T 分期、淋巴血管侵犯、淋巴结转移、肿瘤位置、伴随的变异组织学和非乳头状大体发现有关。多变量 Cox 分析显示 LVI 和高肿瘤出芽是尿路上皮外复发的独立预测因子。P  = 0.039 和 0.014，风险比分别 = 2.50 和 2.88），高肿瘤出芽是总生存期的独立预测因子（P  = 0.024，风险比 = 2.33）。肿瘤出芽可以很容易地引入临床实践，无需免疫组织化学分析，可能是 UUTUC 的重要临床病理因素，并被认为可作为侵袭性 UUTUC 患者的新型预测预后因素。