Tae Wook Kang1, Hyunchul Rhim2, Kyoung Doo Song1, Min Woo Lee1, Dong Ik Cha1, Sang Yun Ha3, Joong Hyun Ahn4. 1. Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-Dong, Gangnam-gu, Seoul, 135-710, Korea. 2. Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-Dong, Gangnam-gu, Seoul, 135-710, Korea. rhimhc@skku.edu. 3. Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-Dong, Gangnam-gu, Seoul, 135-710, Korea. 4. Biostatics Team, Samsung Medical Center, Samsung Biomedical Research Institute, 50 Irwon-Dong, Gangnam-gu, Seoul, 135-710, Korea.
Abstract
PURPOSE: Hepatocellular carcinoma (HCC) with a "nodule-in-nodule" (NIN) appearance has unique histological characteristics as an early HCC. We assessed long-term therapeutic outcomes of radiofrequency ablation (RFA) in HCC patients considering this appearance. MATERIALS AND METHODS: Our Institutional Review Board approved this retrospective study, and the requirement for written informed consent was waived. Between May 2006 and April 2012, a total of 572 patients underwent RFA for single HCC as a first-line treatment. Patients were divided into a NIN HCC group (n = 22) and a non-NIN HCC group (n = 550), according to the NIN feature on pretreatment imaging studies. Local tumor progression (LTP) and disease-free survival (DFS) were compared. Prognostic factors for LTP and DFS were assessed using a Cox proportional hazards model. RESULTS: The cumulative LTP rates were 4.6 and 4.6% at 3 and 5 years, respectively, in the NIN HCC group, and 15.9 and 20.5% in the non-NIN HCC group, with borderline statistical significance (p = 0.085). The corresponding DFS rates were 53.8 and 37.7% in the NIN HCC group and 44.0 and 31.7% in the non-NIN HCC group, with no significant difference (p = 0.318). Although on multivariate analysis only tumor size was a significant prognostic factor for LTP, there was a trend bordering on the significance for the NIN feature [hazard ratio (HR) = 0.19; p = 0.099]. However, it was not a significant factor for DFS (HR = 0.18; p = 0.682). CONCLUSIONS: The NIN appearance, a rare (4%, 22/550) but unique feature of early HCC, may be a favorable prognostic factor for RFA in terms of local tumor control.
PURPOSE:Hepatocellular carcinoma (HCC) with a "nodule-in-nodule" (NIN) appearance has unique histological characteristics as an early HCC. We assessed long-term therapeutic outcomes of radiofrequency ablation (RFA) in HCC patients considering this appearance. MATERIALS AND METHODS: Our Institutional Review Board approved this retrospective study, and the requirement for written informed consent was waived. Between May 2006 and April 2012, a total of 572 patients underwent RFA for single HCC as a first-line treatment. Patients were divided into a NIN HCC group (n = 22) and a non-NIN HCC group (n = 550), according to the NIN feature on pretreatment imaging studies. Local tumor progression (LTP) and disease-free survival (DFS) were compared. Prognostic factors for LTP and DFS were assessed using a Cox proportional hazards model. RESULTS: The cumulative LTP rates were 4.6 and 4.6% at 3 and 5 years, respectively, in the NIN HCC group, and 15.9 and 20.5% in the non-NIN HCC group, with borderline statistical significance (p = 0.085). The corresponding DFS rates were 53.8 and 37.7% in the NIN HCC group and 44.0 and 31.7% in the non-NIN HCC group, with no significant difference (p = 0.318). Although on multivariate analysis only tumor size was a significant prognostic factor for LTP, there was a trend bordering on the significance for the NIN feature [hazard ratio (HR) = 0.19; p = 0.099]. However, it was not a significant factor for DFS (HR = 0.18; p = 0.682). CONCLUSIONS: The NIN appearance, a rare (4%, 22/550) but unique feature of early HCC, may be a favorable prognostic factor for RFA in terms of local tumor control.