Feature selection is an effective approach to reduce the number of features of data, which enhances the performance of classification in machine learning. In this paper, we formulate a joint feature selection problem to reduce the number of the selected features while enhancing the accuracy. An improved binary particle swarm optimization (IBPSO) algorithm is proposed to solve the formulated problem. IBPSO introduces a local search factor based on Lévy flight, a global search factor based on weighting inertia coefficient, a population diversity improvement factor based on mutation mechanism and a binary mechanism to improve the performance of conventional PSO and to make it suitable for the binary feature selection problems. Experiments based on 16 classical datasets are selected to test the effectiveness of the proposed IBPSO algorithm, and the results demonstrate that IBPSO has better performance than some other comparison algorithms.

Introduction Hepatocellular carcinoma (HCC) has been the second leading cause of cancer-related death in China. Radiofrequency ablation is a relatively novel treatment that may improve the treatment of HCC. Aim To evaluate and compare the efficacy and safety of radiofrequency ablation (RFA) versus laparoscopic liver resection (LLR) in the treatment of HCC. Material and methods We searched for relevant published studies in English (PubMed, Cochrane Library, EMBASE) and in Chinese (CBM, CNKI and Wanfang) from their inception until September 23, 2019. The quality of included studies was evaluated by the Newcastle-Ottawa Scale. Results A total of 19 retrospective studies including 2038 patients were eligible for the meta-analysis. The results of the meta-analysis demonstrated that LLR was superior to RFA in terms of 3-year overall survival rate (OR = 0.62), 1 to 3-year disease-free survival rates (OR = 0.57; OR = 0.41, respectively) and local recurrence rates (OR = 2.71). Conclusions The meta-analysis demonstrates that laparoscopic liver resection should be preferred in tumors of size 3–5 cm, while for < 3 cm the long term results are equal.

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Context: Hepatocellular carcinoma (HCC) is a common malignant cancer and the second leading cause of cancer-related deaths around the world. Radiofrequency ablation (RFA) and laparoscopic hepatectomy (LH) have been adopted for the treatment of HCC. The aim of the meta-analysis was to explore the long-term efficacy of RFA compared with LH for small HCC (sHCC) patients in the East Asian population. Evidence Acquisition: We performed a systematic review and meta-analysis by the literature search on PubMed, Cochrane Library, EMBASE, Chinese Biological Medical Literature (CBM), Chinese National Knowledge Infrastructure (CNKI), and Wanfang from their inception until October 10, 2019, for comparing the long-term efficacy outcomes of RFA with LH. Results: Fourteen retrospective studies with 1,390 subjects were included in the meta-analysis. Compared with the LH-treated group, RFA could raise the local recurrence rate under median follow-up duration and reduce disease-free survival (DFS) rates at 1 - 3 years. However, it failed to affect 5-year overall survival (OS) and DFS rates. In the subgroup analyses, different RFA approaches had significantly higher local recurrence rates than the LH group. A similar effect on OS and DFS rates within five years for single early (≤ 3 cm) HCCs and on the 1- and 5-year DFS rates for nodules ≤ 5 cm were observed between the two groups, but RFA approaches could reduce the 3-y OS and DFS rates for single nodules ≤ 5 cm. The percutaneous radiofrequency ablation (PRFA) group had significantly lower 3- and 5-year OS and the 1- and 3-year DFS rates than the LH group, while no significant difference in OS and DFS rates in the laparoscopic radiofrequency ablation (LRFA) approach. The RFA approach improved the 3-year OS compared with the LH group in Japan, but reduced the 3-year OS and DFS rates within 3 years in China. Conclusions: Our results support that LH treating sHCC had a better long-term efficacy and a lower local recurrence rate than RFA in the East Asian population. Further high-quality prospective studies are required to confirm the long-term efficacy.

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