Overview

This is a phase II clinical trial testing whether a combination of stereotactic ablative radiotherapy (SABR), axitinib, and toripalimab is effective and safe for treating oligometastatic clear cell renal cell carcinoma (a type of kidney cancer that has spread to 5 or fewer sites).

In this study, all metastatic tumors will be treated with SABR - a precise, high-dose radiation therapy delivered in 5 sessions. At the same time, participants will receive axitinib (an oral targeted cancer drug) twice daily, and toripalimab (an intravenous immunotherapy) every 3 weeks for up to 2 years.

The study will enroll 48 participants. The main goal is to measure the objective response rate - the proportion of patients whose tumors shrink or disappear after treatment. Researchers will also track how long patients live without their cancer worsening, overall survival, and any side effects from the treatment.

Participants will have regular imaging scans, blood tests, and quality-of-life assessments throughout the treatment and follow-up period.

Eligibility

Inclusion Criteria:

Histologically confirmed diagnosis of clear cell renal cell carcinoma (ccRCC).

Age ≥ 18 years.

Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.

Radiological evidence of distant metastasis meeting the MD Anderson (MDA) definition of oligometastatic disease: ≤5 metastatic lesions, all amenable to curative-intent local therapy. Lesions must be measurable per RECIST 1.1 criteria.

Prior definitive local therapy to the primary tumor, including surgery, stereotactic radiotherapy, or ablation.

Either no prior systemic therapy for metastatic disease (first-line naïve), or prior first-line tyrosine kinase inhibitor (TKI) therapy only with subsequent oligoprogression (≤5 progressive lesions with remaining lesions stable).

Adequate organ function:

Hemoglobin (Hb) ≥ 80 g/L

Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L

Platelet count (PLT) ≥ 75 × 10⁹/L

Serum total bilirubin ≤ 1.5 × upper limit of normal (ULN)

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 × ULN

Prothrombin time (PT) and activated partial thromboplastin time (aPTT) ≤ 1.5 × ULN

Voluntary written informed consent obtained, with commitment to complete all treatment and follow-up visits.

Exclusion Criteria:

Target lesions previously treated with radiotherapy with a biologically effective dose (BED₃) ≥ 60 Gy (calculated with α/β = 3 Gy).

Target lesions deemed unsuitable for radiotherapy by the treating radiation oncologist (e.g., lesions invading the gastrointestinal tract or penetrating the bronchus).

Uncontrolled malignant pleural effusion or ascites.

Presence of other uncured malignancies.

History of severe psychiatric illness interfering with understanding of informed consent or compliance with study procedures.

Severe cardiovascular disease: New York Heart Association (NYHA) class III-IV heart failure, uncontrolled arrhythmia, or myocardial infarction within the past 6 months.

Any other serious medical condition that, in the investigator's judgment, may pose significant risk or interfere with radiotherapy.

Pregnancy, breastfeeding, or planned pregnancy during the study period.

Any other reason determined by the investigator that makes the participant unsuitable for study participation.