HCC is a highly malignant tumor, a majority of HCC patients are already in the late stage when diagnosed, thus leading to a poor prognosis. Early diagnosis and treatment are effective methods to prolong the survival time of HCC patients[28]. Due to the radiological nature of imaging examinations, patients cannot be routinely examined. Therefore, more and more researches turn to focus on the discovery of HCC through serum tumor markers. At present, AFP is a serum tumor marker often used to monitor HCC, and it locates on the ribosomes of the rough endoplasmic reticulum of liver cells. When HCC occurs, the metabolism of patients gets accelerated, which in turn promotes the synthesis of AFP. Therefore, a significant increase of serum AFP levels can indicate the occurrence of HCC. However, serum AFP in some HCC patients is negative or in a low level, and the level of serum AFP also gets increased in some patients with benign liver diseases, which leads to a significant increase of misdiagnosis rate of HCC[29]. Therefore, it is necessary to combine serum AFP detection with other serological indicators to achieve an early diagnosis of HCC.
This study explored the clinical value of three markers of AFP, AFP-L3 and CTCs in the diagnosis of HCC, liver cirrhosis, and hepatitis, when used alone or in combination. Firstly, the expression levels of serum AFP, AFP-L3 and CTCs in different groups were compared, and the results showed that the levels of serum AFP, AFP-L3 and CTCs of patients in HCC group were significantly higher than those in other groups. A comparison of the positive rates of serum AFP, AFP-L3, and CTCs showed that the positive rate of CTCs in the HCC group was the highest. Besides, a comparison of the positive rate of combined detection of AFP, AFP-L3 and CTCs indicated that the positive rates in HCC group increased significantly when AFP was paired with AFP-L3, or with CTCs, or combined with both AFP-L3 and CTCs, or when AFP-L3 was paired with CTCs. The data above indicates that when AFP is combined with CTCs and AFP-L3 in the detection, it would play a complementary role in the clinical diagnosis of HCC. The rational use of these markers can promote the positive rate and the accuracy of diagnosis, meanwhile, it helps to reduce the rate of missed diagnosis and misdiagnosis.
ROC curve was used to analyze the clinical value of single and combined detection of serum AFP, AFP-L3, and CTCs in the early diagnosis of HCC. The results showed that a combined detection of AFP, AFP-L3 and CTCs increased the early diagnosis of HCC, and it’s better than the detection of single indicator or paired indicators. AFP-L3 is a specific α-fetoprotein generated by liver cancer tissues, and it is mainly found in the serum of HCC patients. The increase of patients’ serum level may be linked with the increasing number of AFP-L3 molecules generated by liver cancer cells, which reflects the heterogeneity of benign and malignant cells[30]. The increase of AFP-L3 relies not on the increase of AFP, but is only linked with the benignity and malignancy of liver diseases. Therefore, when the serum AFP level of HCC patients is not highly expressed, AFP-L3 would increase significantly, which means it can play a crucial role in HCC early diagnosis[31]. Compared with traditional detection methods such as tissue biopsy, CTCs detection is real-time, highly efficient and reproducible[32]. CTCs detection has become a promising form of detection and drug target in the researches on early diagnosis, prognostic evaluation and monitoring of HCC, recurrence and metastasis mechanisms. In addition, CTCs detection could develop a multi-marker model when combined with other biomarker detection methods, promoting the sensitivity and specificity of diagnosis to a level above 90%[33], which is consistent with the results of this study.
In recent years, with the development of minimally invasive technology and the renewal of treatment concepts, surgical resection is no longer the only choice in the treatment of HCC. MWA is a new technique of local thermal ablation, which featured as rapid rise of temperature, easy to operate and repeatable. It can evaporate water near the lesion quickly through the high-frequency vibration heating mechanism of dipole and ion, leading to the degeneration, coagulation, and necrosis of tumor cells. MWA also could speed up blood clotting, resulting in a complete necrosis in the coagulation area, and realize the local inactivation[34, 35]. However, MWA treatment of HCC has been found to have certain limitations in clinical practice. Since part of the tumor lesions cannot be completely ablated, it may lead to local recurrence after treatment. A new method is thus needed to effectively predict the short-term efficacy, prognosis and recurrence of HCC patients after MWA treatment. In this study, HCC patients treated with MWA were divided into non-recurrent group and recurrent group by considering whether new tumor lesions appeared within 6 months after treatment. The patients were then divided into CR + PR group (good prognosis) and SD + PD group (poor prognosis) according to the relevant standards of short-term efficacy, they were further divided into OS > 3 years group and OS < 3 years group based on the data of overall survival (OS). The results showed that the levels of serum AFP, AFP-L3, and CTCs of patients in non-recurrent group, CR + PR group, and OS > 3 years group were significantly lower than those of patients in recurrent group, SD + PD group and OS < 3 years group (P < 0.05), suggesting that serum AFP, AFP-L3, and CTCs may be valuable indicators in predicting the short-term efficacy, prognosis and postoperative recurrence of HCC patients after MWA treatment.
ROC curve was used to further analyze the clinical value of single and combined detection of serum AFP, AFP-L3, CTCs in predicting the short-term efficacy, prognosis and postoperative recurrence of HCC patients after MWA treatment. The results indicated that a combined detection of these indicators could significantly improve the levels of AUC, sensitivity and specificity, and it had a better predictive value than single or paired indicators. AFP-L3 is a new generation of liver cancer biomarker, and as a specific α-fetoprotein generated by liver cancer cells, it has a high accuracy, specificity, and sensitivity. AFP-L3 is often used in combination with AFP in the clinical diagnosis, efficacy judgment, prognosis evaluation, and postoperative recurrence monitoring of HCC patients[36]. It has been found in the study that the changes of CTCs in patients’ peripheral blood after treatment can reflect the treatment effect. The decrease or disappearance of CTCs in patients’ peripheral blood often indicates a good treatment effect, if CTCs in patients’ peripheral blood remain unchanged or increased again after initial decrease, it often indicates an unfavorable treatment effect and a tumor recurrence, or indicates a drug resistance. Ye et al. [38] studied the relationship between CTCs and the clinical outcome of patients of hepatitis B-related hepatocellular carcinoma who received radical resection, and found that the DFS and OS of patients with lower CTCs were significantly prolonged compared with patients with higher CTCs, suggesting that higher CTCs might be an independent signal of poor prognosis of HCC patients. Yu et al.[39] studied the changes of CTCs in HCC patients after hepatectomy, and the results indicated that patients with increased CTCs after surgery had significantly shorter DFS and OS compared with patients without CTCs increase; patients had the worst prognosis when CTCs ≥ 2 before and after the surgery, and patients would have the longest DFS and OS when CTCs < 2. Chen et al.[40] retrospectively analyzed the CTCs levels and histopathologic types of 195 patients with hepatocellular carcinoma, and concluded that the total number of CTCs was related to BCLC staging, metastasis, and serum AFP levels. They also found recurrent patients had higher levels of mixed CTCs and mesenchymal CTCs, indicating that the number of CTCs and EMT classification were related to the prognosis of liver cancer. The above research results show that HCC patients’ CTCs levels after surgery are significantly linked with the efficacy, prognosis, and postoperative recurrence. Therefore, the combined detection of serum AFP, AFP-L3 and CTCs has a good predictive value.
In summary, the combined detection of serum AFP, AFP-L3, and CTCs can effectively make up for the shortcomings of detection of single and pairwise indicators. It can not only be used for early diagnosis of HCC, but also has a good clinical value in predicting the short-term efficacy, prognosis and recurrence of HCC patients after MWA. Such a detection method is simple, stable, reliable, economical and practical, and is suitable for application in hospitals at all levels.