Local Ablation Plus Systemic Therapy for Metachronous Liver and/or Lung Oligometastases From Nasopharyngeal Carcinoma

Inclusion Criteria: * Written informed consent to participate in the trial * Age 18 to 75 years, any sex * Histologically or cytologically confirmed nasopharyngeal carcinoma, with clinically diagnosed liver and/or lung metastases * Primary nasopharyngeal tumor cured after curative treatment, with no lymph node metastasis and no metastases outside the liver and lung (metachronous metastasis: distant metastasis detected at least 6 months after curative treatment of the primary tumor) * No more than 5 liver and/or lung metastases, each 3 cm or smaller in diameter * Liver and/or lung metastases amenable to ablation * ECOG performance status 0 or 1 * Adequate hematologic and organ function: absolute neutrophil count ≥1.5×10\^9/L; hemoglobin ≥70 g/L; platelet count ≥50×10\^9/L; white blood cell count ≥3.0×10\^9/L; serum albumin ≥28 g/L; total bilirubin ≤3.0 mg/dL; AST and ALT ≤5×ULN; serum creatinine ≤1.5×ULN; INR ≤2.3 (without anticoagulant therapy) * No prior systemic therapy for metastatic disease (e.g., gemcitabine plus cisplatin chemotherapy or PD-1 inhibitor) Exclusion Criteria: * History of hypersensitivity or intolerance to any study drug * Severe hepatic insufficiency, pulmonary fibrosis, or pulmonary hypertension * Poorly controlled infectious or radiation-induced inflammation around the lesion, skin infection at the puncture site, systemic infection, or fever \>38.5 °C * Estimated life expectancy less than 3 months * Poorly controlled malignant pleural effusion * Clinically significant bleeding within 30 days before study entry * Uncorrectable coagulopathy or marked hematologic abnormality with evident bleeding tendency * Severe hepatic, renal, cardiac, pulmonary, or cerebral dysfunction; severe anemia, dehydration, or nutritional/metabolic disturbance that cannot be corrected in the short term; left ventricular ejection fraction \<45% * History of congenital long QT syndrome, or corrected QT interval \>480 ms (Fridericia) * Psychiatric disorder in an active episode * Poorly controlled hypertension: systolic blood pressure \>150 mmHg and/or diastolic blood pressure \>100 mmHg * Urine protein ≥1 g/24 h (participants with ≥1+ proteinuria on dipstick must have 24-hour urine protein measured); prior organ transplantation * Anticoagulant and/or antiplatelet therapy (except novel oral anticoagulants such as dabigatran and rivaroxaban) not discontinued for more than 5-7 days before ablation * Other malignancy within the previous 3 years or concurrently * Prior gemcitabine plus cisplatin chemotherapy or PD-1 inhibitor therapy * Any other condition that, in the investigator's judgment, makes the patient unsuitable for the trial