Limitation of Repeated Radiofrequency Ablation in HCC
Limitation of Repeated Radiofrequency Ablation in HCC
Between August 2000 and March 2010, a total of 472 patients received RFA as the initial therapy for HCC within fewer than three tumors, less than 3 cm in maximum size of tumors, and a functional hepatic reserve of Child–Pugh score < 10 points at the Department of Gastroenterology, Fukuoka University Faculty of Medicine (Fukuoka, Japan). HCC was diagnosed when the tumors in the liver met the following criteria: (i) histological confirmation by ultrasound-guided tumor biopsy; and (ii) typical imaging findings by dynamic helical computed tomography (CT) or CT during hepatic angiography. We enrolled these 472 patients in this study. The patients' characteristics are shown in Table 1.
Ultrasound-guided RFA was conducted percutaneously. The average number of sessions per treatment was 2.03. CT during celiac and superior mesentric angiography, or conventional CT scan with contrast medium, was performed 1 month after the initial therapy in order to verify the success of the treatment. If no enhancing tissue at the tumor site was revealed by these imaging tests, we concluded that RFA had been successful. If residual enhancing tissue at the tumor site was observed after RFA, the procedure was repeated within 14 days. As a result, all patients were determined to have been received successful treatment.
All patients were followed for their hepatic functional reserve (Child–Pugh score) and HCC status at least every 3 months by means of clinical examination, biochemistry, and image analyses (abdominal ultrasound or conventional or angiographic CT scan). The hepatic functional reserve end-point was set at < 10 points on the Child–Pugh score (Grade C). When recurrent HCC was detected, the patient received RFA if the tumor met the RFA criteria (≤ 3 nodules, ≤ 3 cm). Tumor end-point was set when the tumor exceeded the RFA criteria.
The investigation checkpoints were: (i) cumulative overall survival rates of the patients who received RFA; (ii) cumulative proportions of first recurrence rates of the patients who received RFA; (iii) cumulative rates of shifts to Child–Pugh grade C; (iv) time period from initial therapy to the point when the RFA criteria was exceeded, as well as the number of RFA sessions to the point when the indication for RFA was exceeded; and (v) factors that contribute to probabilities exceeding the RFA criteria in clinical characteristics before RFA.
Results are presented as the mean ± standard deviation. Cumulative survival rates, progression of hepatic functional reserve, HCC status, and probabilities exceeding the RFA criteria were calculated using Kaplan–Meier estimates. A log–rank test was used for the comparison between each curve. Differences between two groups were analyzed using χ-test. Multivariate analysis was considered using Cox's proportional hazards model to test for significance. P-values less than 0.05 were considered to be statistically significant.
Methods
Between August 2000 and March 2010, a total of 472 patients received RFA as the initial therapy for HCC within fewer than three tumors, less than 3 cm in maximum size of tumors, and a functional hepatic reserve of Child–Pugh score < 10 points at the Department of Gastroenterology, Fukuoka University Faculty of Medicine (Fukuoka, Japan). HCC was diagnosed when the tumors in the liver met the following criteria: (i) histological confirmation by ultrasound-guided tumor biopsy; and (ii) typical imaging findings by dynamic helical computed tomography (CT) or CT during hepatic angiography. We enrolled these 472 patients in this study. The patients' characteristics are shown in Table 1.
Assessment of RFA Results
Ultrasound-guided RFA was conducted percutaneously. The average number of sessions per treatment was 2.03. CT during celiac and superior mesentric angiography, or conventional CT scan with contrast medium, was performed 1 month after the initial therapy in order to verify the success of the treatment. If no enhancing tissue at the tumor site was revealed by these imaging tests, we concluded that RFA had been successful. If residual enhancing tissue at the tumor site was observed after RFA, the procedure was repeated within 14 days. As a result, all patients were determined to have been received successful treatment.
Follow up and Assessment of Disease Progression
All patients were followed for their hepatic functional reserve (Child–Pugh score) and HCC status at least every 3 months by means of clinical examination, biochemistry, and image analyses (abdominal ultrasound or conventional or angiographic CT scan). The hepatic functional reserve end-point was set at < 10 points on the Child–Pugh score (Grade C). When recurrent HCC was detected, the patient received RFA if the tumor met the RFA criteria (≤ 3 nodules, ≤ 3 cm). Tumor end-point was set when the tumor exceeded the RFA criteria.
Investigation Checkpoints
The investigation checkpoints were: (i) cumulative overall survival rates of the patients who received RFA; (ii) cumulative proportions of first recurrence rates of the patients who received RFA; (iii) cumulative rates of shifts to Child–Pugh grade C; (iv) time period from initial therapy to the point when the RFA criteria was exceeded, as well as the number of RFA sessions to the point when the indication for RFA was exceeded; and (v) factors that contribute to probabilities exceeding the RFA criteria in clinical characteristics before RFA.
Statistical Analysis
Results are presented as the mean ± standard deviation. Cumulative survival rates, progression of hepatic functional reserve, HCC status, and probabilities exceeding the RFA criteria were calculated using Kaplan–Meier estimates. A log–rank test was used for the comparison between each curve. Differences between two groups were analyzed using χ-test. Multivariate analysis was considered using Cox's proportional hazards model to test for significance. P-values less than 0.05 were considered to be statistically significant.