SEED-CRYO: Sequential 125I Seed Implantation Followed by Cryoablation vs Single-Modality Local Therapy in Unresectable Solid Tumors

Starting soon · Phase 2

Conditions studied: Unresectable Solid Tumors

In brief

This open-label, randomized Phase II trial evaluates whether sequential iodine-125 seed implantation followed by cryoablation improves local tumor control versus single-modality local therapy (125I seeds alone or cryoablation alone) in unresectable solid tumors. The study is based on a complementary treatment rationale: cryoablation provides rapid cytoreduction of the dominant tumor component, while 125I seed brachytherapy delivers sustained low-dose-rate irradiation that may better suppress residual viable tumor at the periphery and microscopic extension zones. The trial is designed to determine whether this spatial and temporal complementarity translates into superior local disease control without unacceptable toxicity. Participants will be randomized in parallel to one of three arms: (1) sequential 125I seed implantation followed by cryoablation within a protocol-defined interval, (2) 125I seed implantation alone, or (3) cryoablation alone. Treatment assignment is open label; imaging-based efficacy endpoints will be assessed using a standard blinded assessment process (blinded evaluators), according to protocol-defined criteria. The primary endpoint is local control rate (LCR) of prespecified target lesions and progression-free survival (PFS). Key secondary endpoints are local progression-free survival (LPFS), overall survival (OS), early pain response, technical success, target-lesion re-intervention rate, and safety (including grade ≥3 treatment-emergent adverse events, CTCAE v5.0). Exploratory analyses include dosimetry-outcome associations, imaging/radiomics biomarkers, and peripheral blood biomarker dynamics.

Key facts

Study ID

NCT07450352

Run by

Li Min

People needed

150

Starts

2026-02-01

Expected to finish

2028-07-01

Last updated by the study team

2026-03-04

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Adults aged ≥18 years;
• Histologically or cytologically confirmed solid tumor that is unresectable and for which local therapy is clinically appropriate;
• At least one prespecified target lesion suitable for percutaneous image-guided treatment and considered technically feasible for both 125I seed implantation and cryoablation per investigator assessment (and protocol-defined anatomic/dosimetric safety criteria);
• ECOG performance status 0-2;
• Adequate organ function, acceptable coagulation status, and the ability to safely undergo percutaneous image-guided procedures;
• Written informed consent provided.

You may not qualify if…

• Prior 125I seed implantation or cryoablation to the same target lesion(s), or other local therapy to the target lesion(s);
• Target lesion location or anatomy that, in the investigator's judgment, makes either procedure unsafe or unlikely to achieve protocol-defined coverage/ablation (e.g., inability to meet organ-at-risk constraints or required safety margins);
• Uncontrolled bleeding risk or coagulopathy not correctable per protocol; inability to safely hold/bridge anticoagulants/antiplatelets as required.
• Active, uncontrolled infection, including uncontrolled local infection at the intended procedure site;
• Clinically significant uncontrolled comorbidities that increase procedural risk;
• Severe organ dysfunction that precludes procedures or follow-up, per protocol-defined thresholds.;
• Pregnancy or breastfeeding;
• Known hypersensitivity to materials/medications essential for the procedures (e.g., contrast agents or anesthetics) that cannot be adequately managed;
• Any condition that would impair reliable outcome assessment or adherence (e.g., inability to undergo required imaging, expected poor compliance), per investigator judgment.

Where it is running

• The 960th Hospital of People's Liberation Army (PLA) — Jinan, Shandong, China

Full record on ClinicalTrials.gov

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