Histopathologic and immunohistochemical features of tissue adherent to multitined electrodes after RF ablation of liver malignancies can help predict local tumor progression: initial results

PURPOSE

To determine whether histopathologic and immunohistochemical features of tissue adherent to electrodes after radiofrequency (RF) ablation of liver malignancies can help predict local tumor progression (LTP).

MATERIALS AND METHODS

Institutional review board waiver and informed consent were obtained. Histologic and immunohistochemical examinations of tissue adherent to electrodes after RF ablation of liver malignancies were performed, with application of proliferation (Ki-67) and apoptosis (caspase-3) markers. Clinical and technical information were prospectively collected for an HIPAA-registered database. Medical records and imaging were reviewed to determine LTP for treated tumors smaller than 5 cm in diameter. LTP-free and survival rates were assessed with Kaplan-Meier method; differences between groups assessed with permutation log-rank test. Multivariate analysis assessed with Cox regression for factors related to LTP.

RESULTS

Sixty-eight malignant tumors treated with RF ablation were identified. Fifty-five tissue specimens were classified as coagulation necrosis (CN), thermal artifact only, or tumor cells positive for caspase-3/negative for Ki-67; and 13 as viable tumor cells (Ki-67 positive). Mean tumor size was larger in viable (3.4 cm) than in CN (2.5 cm) group before treatment (P = .01). For viable and CN groups, LTP occurred in 12 (92%) of 13 and 16 (29%) of 55 specimens, respectively; 1-year LTP-free rates were 0% and 74%, respectively (P < .001). Multivariate analysis confirmed that viable cells comprise independent risk factor for LTP (P < .001). The odds of LTP is six times greater in viable group compared with CN group for tumors 3-5 cm (hazard ratio: 5.9, 95% confidence interval: 2.4, 14.5) and 10 times greater for tumors smaller than 3 cm (hazard ratio: 10.1, 95% confidence interval: 1.7, 57.5). Median survival was 32.7 months.

CONCLUSION

Evidence of Ki-67-positive tumor cells on the electrode after hepatic RF ablation is an independent predictor of LTP.

Radiofrequency ablation in the management of liver metastases from breast cancer

OBJECTIVE

Systemic chemotherapy remains the standard treatment for patients with breast cancer hepatic metastases. Resection of metastases has survival advantages in a small percentage of selected patients. Radiofrequency ablation has been used in small numbers of selected patients. This small series was undertaken to review our experience with radiofrequency ablation in the management of patients with breast cancer hepatic metastases.

CONCLUSION

Radiofrequency ablation of breast cancer hepatic metastases is safe and may be used to control hepatic deposits in patients with stable or no extrahepatic disease.