Our study suggested RFA achieves long-term survival outcomes similar to repeated SR in small recurring HCCs less than 3cm after primary resection. Previous studies comparing the efficacy of repeated RFA vs. resection after recurrence of HCCs usually also enrolled recurring tumors of more than 3cm in size (25, 28, 30, 31). Actually, following surgical resection of the primary tumors, intensive screening was usually applied and the recurring tumors were usually smaller than 3cm and the recurrent HCCs in our study were relatively small: 46% were smaller than 2cm, which was more like the real situation in the recurrence of tumors. A recent meta-analysis  reported RFA was associated with lower disease-free survival rates, however, our study we found both SR and RFA achieved a similar outcome for recurrent HCCs.. This might be explained by the inclusion criteria whereby the recurrent HCCs in our study were relatively small. As expected, a smaller tumor size is closely related to a higher rate of complete tumor elimination after RFA and a greater safety margin with fewer non-tumorous liver parenchyma resections in repeated SR, so the outcomes will be better. Besides, most RFA were performed under sonogram guidance in previous reports, but most (81%) patients received RFA under CT guidance in our study because the tumor size was usually small and some were not visible by sonogram. Altered anatomy after resection also contributed to difficulty with US guided RFA. Some experts suggested CT-guided RFA provides better detection of RFA lesions, margin discrimination, immediate ablation zone evaluation, and few artifacts , which may achieve better complete tumor ablation and better outcomes. Indeed, the RFA treated group in our study had a better 5-year overall survival rate and disease free survival rates than several previous studies [25–28]. Although in a recent study, Lee et al. found that either US or CT guided RFA was comparable for treatment naïve HCC , there was no study that compared the efficacy and safety of US or CT in the guidance of RFA for recurrent HCC after primary resection. This interesting problem merits further investigation in the future.