PULSAR Radiotherapy Plus Anti-PD-1 Therapy in Metastatic Abdominopelvic Tumors

Inclusion criteria

• Age ≥18 years at the time of enrollment, with no restriction on sex.
• Histologically, cytologically, or radiologically confirmed metastatic abdominopelvic malignancy, including hepatocellular carcinoma, renal cell carcinoma, or urothelial carcinoma.
• No more than 10 metastatic lesions, and the radiotherapy treatment plan indicates that radiotherapy can be safely delivered.
• At least one measurable lesion is present.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
• Determined by a multidisciplinary team (MDT) to require active antitumor treatment.
• Adequate bone marrow, liver, renal, and coagulation function as demonstrated by laboratory tests performed within 7 days prior to the first dose of study treatment; no blood transfusion, blood products, granulocyte colony-stimulating factor (G-CSF), or other hematopoietic growth factors are permitted within 7 days prior to laboratory testing.
• Voluntary participation with written informed consent provided, and willingness to comply with the study treatment protocol and scheduled visits.

Exclusion criteria

• Absolute neutrophil count (ANC) <1.5 × 10⁹/L, or platelet count <100 × 10⁹/L (or <80 × 10⁹/L in patients with liver metastases), or hemoglobin <9 g/dL; blood transfusion within 2 weeks prior to enrollment to meet eligibility criteria is not permitted.
• Serum total bilirubin >1.5 × the upper limit of normal (ULN), or >2.5 × ULN in patients with liver metastases.
• Aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) >2.5 × ULN, or >5 × ULN in patients with liver metastases.
• Estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m².
• Clinically significant electrolyte abnormalities as determined by the investigator.
• Active gastrointestinal diseases, including but not limited to gastric or duodenal ulcers, ulcerative colitis, or active bleeding from unresected tumors; or other conditions judged by the investigator to carry a risk of gastrointestinal bleeding or perforation; or a history of gastrointestinal perforation or fistula that has not fully healed after surgical treatment.
• History of arterial thrombosis or deep vein thrombosis within 6 months prior to enrollment, or evidence or history of bleeding tendency within 2 months prior to enrollment, regardless of severity.
• Stroke or transient ischemic attack within 12 months prior to enrollment.
• Significant cardiac disease within 6 months prior to enrollment, including congestive heart failure, acute myocardial infarction, severe or unstable angina, or coronary artery bypass grafting; or New York Heart Association (NYHA) class II or higher heart failure; or left ventricular ejection fraction (LVEF) <50%.
• Presence of a clinically detectable second primary malignancy at screening, or a history of another malignancy within the past 5 years, except for adequately treated early-stage non-melanoma skin cancer, carcinoma in situ of the cervix, superficial bladder cancer (non-muscle-invasive tumors, carcinoma in situ, or T1 tumors), or early-stage thyroid cancer.
• Known clinically significant liver disease, including but not limited to hepatitis B virus (HBV) infection with positive HBV DNA (≥1 × 10⁴ IU/mL), hepatitis C virus (HCV) infection with positive HCV RNA (≥1 × 10³ IU/mL), or cirrhosis.
• Pregnant or breastfeeding women, women of childbearing potential with a positive pregnancy test prior to first dosing, or participants (or their partners) unwilling to use effective contraception during the study period.
• Any clinical or laboratory abnormality or compliance issue that, in the investigator's judgment, makes the participant unsuitable for participation in this study.
• Presence of severe psychological or psychiatric disorders.