Radiofrequency Ablation (RFA): How It Works and SURF Trial Results

Radiofrequency ablation (RFA) is a local treatment in which a doctor guides a thin needle electrode into a tumor under CT or ultrasound and destroys the tumor with heat produced by a radiofrequency current. In Japan it is often called "radio-wave ablation therapy"; it is the same procedure. In Japan's SURF trial, run at 49 hospitals, patients with small liver cancers (3 cm or less, up to three tumors) who had RFA reached a 5-year overall survival of 70.4%, statistically no different from the 74.6% seen after surgery.

This article draws on the SURF trial published in the Journal of Clinical Oncology (JCO) in 2025, a 10-year follow-up of 1,170 liver cancer patients from the University of Tokyo, a review of RFA principles in Cardiovascular and Interventional Radiology (CVIR), and patient guides from UW Medicine and Penn Medicine's OncoLink. It explains how the heat destroys tumors, who is eligible, what the studies show and what the procedure is like.

One treatment, several names

Patients reading hospital materials from different countries often meet several names for this treatment. Japanese hospitals call it "radio-wave ablation therapy", Korean sources often say "high-frequency thermal therapy", and English papers use radiofrequency ablation. All of them mean RFA.

According to UW Medicine, the only marks left on the skin are small nicks about a quarter of an inch (about 6 mm) long. The treated tumor turns into scar tissue that shrinks over time. Our RFA overview covers the treatment in general.

How heat destroys a tumor

A 2004 review in CVIR by researchers at the US National Institutes of Health (NIH) explains that the radiofrequency current makes ions in the tissue oscillate and generates heat. Tissue held at 50–52°C for 4–6 minutes undergoes coagulation necrosis, and above 60°C cell death is almost immediate. Generators at the time worked at 375–480 kHz.

How much tissue one placement can treat depends on the electrode. If the tip overheats and tissue chars, heat stops spreading, so cooled needles and electrodes with expanding prongs were developed.

Friedman M, et al. CVIR 2004;27(5):427-434. Devices have continued to improve since.

Next to blood vessels wider than 3 mm, flowing blood carries heat away and the tumor edge may be under-treated. This is called the heat sink effect. Doctors therefore aim for a margin of about 1 cm around the tumor, and covering a 3 cm tumor with that margin takes several overlapping ablations. The same review put the practical size limit near 5 cm, which is why results are best for small tumors. For a comparison with a different heating method, see microwave ablation versus RFA for liver cancer.

Who is eligible?

• Small liver cancers: SURF enrolled patients whose largest tumor was 3 cm or less, with no more than three tumors. In the randomized group, 90% had a single tumor and about 65% had tumors of 2 cm or less.
• Patients for whom surgery is a burden: older patients or those with other illnesses can be treated through a single needle.
• Small recurrent liver cancers: new tumors in the same or another part of the liver can be ablated again.
• Other organs: OncoLink lists kidney tumors, lung cancer and lung metastases, liver metastases from colon and breast cancer, and bone metastases.

Blood tests of liver function are essential before liver RFA; see tests before liver cancer procedures. Lung tumors are covered in our lung cancer RFA guide.

SURF trial: 5-year survival equal to surgery

A team led by Professor Kiyoshi Hasegawa at the University of Tokyo enrolled 1,094 patients with small liver cancers at 49 hospitals in Japan between 2009 and 2015. Of these, 302 were randomly assigned to surgery (150) or RFA (152) (SURF-RCT), and 753 who declined randomization were followed after choosing their own treatment (SURF-Cohort). The results were published in JCO in 2025.

Kawaguchi Y, Hasegawa K, et al. J Clin Oncol 2025, doi:10.1200/JCO-24-02030.

The investigators concluded that surgery was not shown to be superior to RFA for small liver cancer. In practical terms, suitable patients with small tumors can weigh needle-based RFA alongside surgery as an equal option. When cancer came back, 58.1% of the surgery group and 57.9% of the RFA group were treated again with RFA, showing that it can be repeated. For RFA combined with embolization in intermediate-stage disease, see the TORCH phase 3 trial of TACE plus RFA.

University of Tokyo: 1,170 patients over 10 years

The best-known long-term data come from Shuichiro Shiina's team at the University of Tokyo, who analyzed 2,982 RFA treatments in 1,170 patients with primary liver cancer and published the results in the American Journal of Gastroenterology in 2012.

Shiina S, et al. Am J Gastroenterol 2012;107(4):569-577.

The striking figure is that regrowth at the treated site stayed at 3.2% even after 10 years: a tumor that has been fully ablated rarely returns in the same place. Because the selection criteria differ from SURF, the survival figures should not be compared directly. Liver cancer often appears in new parts of the liver, so regular scans that catch new tumors early, followed by repeat treatment, are key to long-term survival.

The procedure and recovery

Anesthesia and length of stay vary between hospitals. Two US university patient guides side by side show the range.

Based on the UW Medicine interventional radiology guide and the OncoLink guide.

Call the care team for a fever above 101°F (38.3°C), belly pain that does not settle, or bleeding that soaks the dressing. Success is checked with contrast CT or MRI: an area that no longer takes up contrast indicates that the tumor tissue has died. More on hospital stay and recovery is in liver cancer RFA: procedure and recovery time.

Japan and other countries

International patients are usually not covered by the host country's public insurance, so confirm costs and scheduling directly with the hospital.

Japan has led large-scale research on RFA for small liver cancer. Both the big randomized trial and more than a decade of follow-up data come from Japanese hospitals, and Japanese specialists draw on this experience to choose between surgery and RFA together with each patient.

Questions to ask your doctor

• Are the size and number of my tumors within the range RFA can treat?
• Is there a large blood vessel or bile duct next to the tumor, and how will you handle it?
• Given my liver function, is surgery or RFA a better fit?
• Will I have general anesthesia or sedation, and how long will I stay?
• When and with which scan will you check the result?

For more preparation tips, see five questions to ask before an RFA consultation and our IVR overview.

Frequently asked questions

Is radio-wave ablation different from radiofrequency ablation?

No. "Radio-wave ablation therapy" is the name used in Japanese hospital materials for radiofrequency ablation (RFA). The principle, equipment and procedure are the same.

Is survival the same if I choose RFA instead of surgery?

For small liver cancers of 3 cm or less and up to three tumors, there was no difference. In Japan's randomized SURF trial, 5-year survival was 74.6% after surgery and 70.4% after RFA, statistically the same, and no serious adverse effects were reported with RFA. Tumor location and liver function still shape the best choice, so decide together with your doctors.

How large a tumor can RFA treat?

The usual threshold is 3 cm or less. Because doctors burn a margin of about 1 cm around the tumor, larger tumors need several overlapping ablations. The CVIR review put the practical limit near 5 cm. For larger tumors, combining RFA with embolization may be considered.

Can RFA be repeated if the cancer comes back?

Yes. In the SURF trial, more than half of patients with recurrence (58.1% in the surgery group and 57.9% in the RFA group) were treated again with RFA. Because it is done through a needle and is gentle on the body, it can be repeated.

This article summarizes international official materials and papers as general information and is not medical advice. Please make treatment decisions with doctors who have examined the patient.