This is a prospective cohort study aimed at clarifying the predictive value of MRD for postoperative DFS and OS in high-risk recurrent renal cell carcinoma patients who have undergone radical nephrectomy and received adjuvant treatment with Toripalimab. Further differentiating patients who need adjuvant immunotherapy.

The study population is high-risk recurrent renal cell carcinoma patients who have undergone radical nephrectomy and meet the criteria of ECOG Score 0-1, no residual tumor on imaging. The study subjects will undergo MRD testing about 3 weeks after surgery, and the drug will be started within 4 weeks of surgery. Imaging (CT, MRI) will be performed from the first dose of Toripalimab, every 12 weeks, and DFS will be evaluated. Survival will be recorded every 3 months. The study aims to investigate the predictive value of MRD technology for DFS and OS in these patients after surgery and provide reference for distinguishing patients who need adjuvant immunotherapy.

1. There must be a histological diagnosis of renal cell carcinoma, with or without sarcomatoid features of clear cell components.

2. On the day of signing the informed consent form, both males and females must be at least 18 years old.

3. The participants provide written informed consent for the trial before enrollment.

4. Have high risk or M1 NED renal cell carcinoma as defined by the following pathological tumor-node-metastasis and Fuhrman grading status.

   1. High risk RCC

      • pT4, Any Gr. N0, M0
      • pT Any stage, Any Gr., N+, M0

   2. M1 NED RCC (participants who present not only with the primary kidney tumor but also solid, isolated, soft tissue metastases that can be completely resected at the time of nephrectomy)

5. No previous systemic treatment for advanced RCC (except nephrectomy or pyelectomy) has been performed.

6. Radical nephrectomy (and complete resection of metastatic lesions in M1 NED participants) was performed with a negative surgical margin.

7. It must be evaluated by the investigator as tumor-free and verified by imaging such as CT or MRI. No suspicious brain metastases.

8. Have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1.

9. Non-surgical sterilization or female participants of childbearing potential who are required to use a medically approved contraceptive method (such as an IUD, contraceptive pill or condom) during the study treatment period and for 3 months after the end of the study treatment period; Serum or urine HCG tests must be negative for women of non-surgical sterilization or childbearing age within 7 days prior to study enrollment; And must be non-lactation period; Non-surgical sterilization or male patients of childbearing age who consent to use a medically approved contraceptive method with their spouse during the study treatment period and for 3 months after the end of the study treatment period.

10. Vital organ function meets the following requirements (excluding use of any blood components and cell growth factors within 14 days) : normal bone marrow reserve function; Absolute neutrophil count (ANC)≥1500/µL, Platelets≥100 000/µL, Hemoglobin ≥5.6 mmol/L (9g/dL); Normal renal function or serum creatinine ≤1.5 mg/d and/or creatinine clearance ≥30 mL/min for participants with creatinine levels >1.5×institutional ULN; Normal liver function or Total bilirubin ≤1.5xULN, or direct bilirubin≤ULN for participants with total bilirubin levels >1.5×ULN; AST (SGOT) and ALT (SGPT) ≤2.5×ULN; International normalized ratio (INR) or prothrombin time (PT) ≤1.5×ULN.

Participants with high-risk recurrent renal cell carcinoma after radical nephrectomy who are older than 18 years of age must have a clear pathological diagnosis and meet all enrollment criteria. The subjects voluntarily join the study and have good compliance with safety and survival follow-up.