treatment of primary focal resection plus lymph node dissection combined with chemotherapy and anti-programmed cell death 1(PD-1) for Oligometastasis of urothelial carcinoma.

The study is designed to demonstrate that Whether the perioperative comprehensive treatment of primary focal resection plus lymph node dissection combined with chemotherapy and anti-PD-1 can prolong the overall survival of patients, narrow the range of metastatic lesions and improve the quality of life of patients.

Compared with patients with extensive metastasis, 2-year tumor-specific survival and overall survival of patients with oligometastatic bladder cancer were significantly increased (53.3% vs 16.1%)；(51.9% vs. 15.4%).Gemcitabine plus cisplatin (GC) regimen has been shown to bring clinical benefits in neoadjuvant therapy of metastatic UC（urothelial carcinoma）.

PD-1 inhibitors have been widely used in urothelial carcinoma in recent years, and positive data have been obtained in both advanced patients and neoadjuvant patients.

If successful in this trial, it will serve to provide a therapeutic alternative for this patient who have oligometastasis of urothelial carcinoma.

Inclusion Criteria:

• Patients with oligometastatic urothelial carcinoma, including :patients with T2-T4 with any metastasis urothelial carcinoma diagnosed by pathology and evaluated by imaging. 1. Patients with measurable oligometastasis or with local lymph node metastasis. Measurable oligometastasis includes: A. a solitary metastatic organ, B. number of metastatic lesions of ≤3, C. the largest diameter of metastatic foci of ≤5cm, D. absence of liver metastasis. 2. Local lymph node metastasis includes: M0 patients with the short diameter of pelvic lymph nodes was ≥8 mm. The researchers assessed the benefits of excision of the primary lesion.
• Older than 18 years old.
• Volunteer to participate in the trial, be able to provide a written informed consent, and understand and agree to comply with the study requirements and evaluation schedule.
• Eastern Cooperative Oncology Group (ECOG) performance status <2
• International standardized ratio or activated partial thrombin time ≤1.5 upper limit of normal value (ULN);The calculated creatinine clearance rate was ≥60ml/min;Serum total bilirubin ≤1.5×ULN;aspartate transaminase(AST), Alanine transaminase(ALT) and alkaline phosphatase ≤2.5×ULN;
• Non-pregnant or fertile men or women must be willing to take effective contraceptive measures during the study period and ≥120 days after the last administration of tislelizumab, and the women should be negative on urine or serum pregnancy test results less than or equal to 7 days before enrollment.

Exclusion Criteria:

• Previous therapy targeted at PD-1, PD-L1, PD-L2, Cytotoxic T-Lymphocyte Associated Protein 4(CTLA-4)or other antibodies or drugs specifically targeting T cell synergistic stimulation or checkpoint channels.
• Other approved systemic anti-cancer therapies or systemic immune modulators (including but not limited to interferon, interleukin-2, and tumor necrosis factor) were received within 28 days prior to enrollment.
• Severe chronic or active infections requiring systemic antimicrobial, antifungal, or antiviral therapy within 14 days prior to enrollment.
• Major surgery or major trauma occurred within 28 days prior to enrollment.
• Live vaccine was administered within 28 days before enrollment.
• Received any herbal or proprietary Chinese medicine used to control cancer in the 14 days prior to enrollment.
• Active autoimmune disease requiring long-term use of large amounts of hormones and other immunosuppressive agents.
• The researchers identified abnormalities in potassium, sodium, calcium, or hypoalbuminemia, interstitial lung disease, non-infectious pneumonia, or other uncontrolled whole-body diseases, including diabetes, hypertension, and cardiovascular disease, that may affect treatment.
• A history of HIV, hepatitis B virus(HBV)and hepatitis C virus(HCV) infection is known.
• A history of known allergic reactions to any of the drugs studied.
• Is participating in additional clinical studies.
• The researcher believes that the patient is not suitable to participate in this study (such as the treatment that does not meet the patient's greatest benefit, patient compliance, etc.)