A large Italian study is shifting the blame for tumor seeding from radio-frequency ablation to biopsies performed to diagnose hepatocellular carcinoma.

Research presented on Wednesday by Dr. G. Scott Gazelle, an associate professor of radiology at Massachusetts General Hospital, was inspired by a 2001 study conducted by Dr. Joseph M. Llovet of the Barcelona-Clinic Liver Cancer Group (Hepatology 2001;33(5):1124-1129). That study reported tumor seeding in four of 32 hepatocellular carcinoma patients who were treated with ultrasound-guided percutaneous RF ablation.

Those patients presented various risk factors, including a subcapsular tumor, poor tumor differentiation, and high baseline alfa-fetoprotein (AFP) levels, but the findings were worrisome for interventional radiologists who perform RF ablations. Biopsies were performed before tumor ablation in all cases.

The results described at the RSNA conference were a reprieve of sorts for RF ablation. Principal investigator Dr. Tito Livraghi, chief of radiology at Ospedale Civile in Milan, Italy, identified tumor seeding in only seven of 908 patients treated at three European hospitals. Biopsies had been performed in 71% or five of seven of the tumor seeding cases, compared with 12% or 111 of 908 patients in the retrospective study.

No hospital was responsible for more that four tumor seeding incidents. Two cases involved subcapsular HCC lesions, and the tumors were poorly differentiated in two other cases.

"Biopsy is clearly a culprit," Gazelle said. "Biopsy before ablation, especially for subcapsular or poorly differentiated tumors, can lead to tumor seeding. Before we were doing ablations, we worried about biopsies of superficially located lesions. The lesson is that if patients can be adequately diagnosed without biopsies, we probably should not perform them."