The 7th Congress of the Asian Society of Cryosurgery was held in Beijing recently in the backdrop of further promoting the technical standardization of minimally invasive tumor treatment and better playing its role in comprehensive tumor treatments. Renowned experts in the fields of tumor interventional and minimally invasive treatment from all over Asia exchanged ideas and gave lectures on cutting-edge subjects, new technologies, and new concepts in related fields. President Xu Kecheng, President Niu Lizhi, and Vice President Liang Bing of Guangzhou Fuda Cancer Hospital delivered speeches.
At the opening ceremony, the honorary president of the congress, Professor Nikolai Korpan of the International Institute of Cryosurgery in Vienna, Austria, Professor Xu Kecheng of Guangzhou Fuda Cancer Hospital, Professor Xiao Yueyong of the First Medical Center of Chinese PLA General Hospital, and the president, Professor Wang Hongwu of Dongzhimen Hospital of Beijing University of Chinese Medicine delivered speeches respectively to welcome the participating representatives.
Highlights
Xu Kecheng —— the Remote Effect of Cryosurgery
Prof. Xu introduced Fuda’s experience in cryoablation over the past 20 years and shared about the remote effect of cryotherapy. Cryotherapy is an ablation therapy that uses localized low temperature to eliminate tumor lesions. Compared with thermal ablation therapies, cryoablation has a more immunological effect. It can not only eliminate tumors, but also release antigens, stimulate the body's immune cells, and promote immune function.
Under the influence of low temperature, tumor cells are mechanically damaged, and the tumor antigens are release as cell membrane and organelles ruptured. These antigens are captured and absorbed by antigen-presenting cells such as dendritic cells (DC cells), and then present their signals to T cells, in which residual local tumors cells and distant metastases can be killed and prevent tumor recurrence. That is, after cryoablation of the primary lesion, distant metastatic lesions also disappeared, which being called the remote effect of cryosurgery.
To enhance the effect, it is necessary to optimize the process. It is now generally believed that necrosis is the main cause of remote effects instead of apoptosis. The middle part of the ice ball caused tumor cell necrosis, while the edge of the ice ball caused cell apoptosis. Therefore, the future direction of cryotherapy should be based on improving probe technology and ultrasound technology, together with physical cofactors, to produce more necrotic areas and less apoptotic areas.
In addition, combine cryosurgery with other treatments will also be an important direction of future development of cryotherapy. For instance, small doses of cyclophosphamide are used clinically to regulate and enhance immunity. It can well preserve the natural structure of tumor antigens, in which is more likely to produce tumor-specific adaptive immune responses and produce remote effects. Therefore, cryoablation is more suitable for use in combination with various immunotherapies like PD-1.
Niu Lizhi —— Cryoablation of Pulmonary Nodules
Pulmonary nodules are common seen in benign than malignant. In some cases, benign pulmonary nodules may undergo malignant transformation as time goes by, especially ground-glass nodules which have a higher rate of malignant transformation. Then how to handle these nodules? Currently, according to NCCN guidelines, surgery is still the first choice. But surgery can’t be performed endless. If the patient is unable to undergo surgery or refuses surgery due to age, poor cardiopulmonary function, multiple pulmonary nodules, or afraid postoperative recurrence and metastasis, cryoablation and thermal ablation are currently available options.
Compared with thermal ablation, cryoablation causes less pain and stimulation to the body when the lesion is close to the chest wall, and would not easily form "lung cavities" like thermal ablation does while freezing the tumor to death. For pulmonary nodules that relatively central, adjacent, or invade the mediastinum or chest wall, cryoablation has more advantages. The dual-probe method can frame ground-glass pulmonary nodules properly, improving the accuracy, success rate and efficiency of cryoablation of small lung cancer. Cryosurgery can achieve satisfactory clinical results when the edge of the ice ball is 1.0 cm larger than the edge of the tumor. After extensive research and practice, three-cycle cryoablation has been shown to have lower recurrence and complication rates.
In addition, for the treatment of small pulmonary nodules, lung puncture biopsy and simultaneous cryoablation therapy can be performed at once to meet diagnosis and treatment needs. It can also reduce the risk of pneumothorax, bleeding, etc. caused by repeated punctures, avoid thoracotomy, and do not affect the patient's daily life. After ablation, combined radiotherapy and/or chemotherapy can be continued.
Currently, cryoablation is being used more and more widely, but the number of cases of patients with pulmonary nodules treated with cryoablation technology is relatively small compared with surgery, which require further clinical research.
Liang Bing —— Cryoablation Combined with Immunotherapy for Liver Cancer
Tumor ablation therapy is one of the important treatment methods for multidisciplinary comprehensive treatment of liver cancer. It has the advantages of small trauma, fast recovery, repeatability, wide indications, and precisely. It can clinical cure early-stage liver cancer and also has good treatment result for mid- and late-stage liver cancer. Among them, cryoablation is recommended in the 2010 NCCN liver cancer treatment guidelines.
cryoablation can form different shape of ice balls by puncturing cryo-probes within the lesion and nearby tissue structures with different temperatures, which can avoid irreversible damage to the gallbladder, intestines and diaphragm. Also, it is safer for unusual parts such as those adjacent to the liver surface, diaphragm, gallbladder, liver hilus, etc.
It is worth noting that Complications of liver puncture ablation are a prominent clinical issue, but adequate preoperative assessment and preparation, precise intraoperative guidance, meticulous puncture, reasonable needle insertion, and real-time intraoperative and postoperative monitoring can effectively avoid complications.
The diversity and complexity of the mechanisms of liver cancer have brought great difficulties to clinical treatment, and it is difficult for a single treatment method to achieve good results. In recent years, unresectable mid- and late-stage liver cancer can be treated with a combination of vascular interventional therapy, brachytherapy, targeted therapy, traditional Chinese medicine, and immunotherapy. cryoablation can not only control the primary tumor, but also induce specific or non-specific anti-tumor responses, producing "remote effect." With the emergence of new anti-tumor immunotherapies such as immune checkpoint inhibitors PD-1/PD-L1 and CAR-T in recent years, immunotherapy has become a new direction in tumor treatment. A large number of clinical applications have shown that the combination of cryoablation, radiotherapy, chemotherapy, and immunotherapy for liver cancer achieves positive effects.
▲Issued plaques for ‘demonstration unit of cryoablation’
Nowadays, China’s cryoablation technology has taken a leading position in the world. As the president unit of the International Society of Cryotherapy and the Training Centre of Cryosurgery in Asia Pacific, Guangzhou Fuda Cancer Hospital has accumulated rich experience in cryotherapy, attracting patients from all over the world, as well as Doctors from South Korea, Malaysia, Indonesia, the Philippines and many hospitals in Taiwan, Hong Kong and mainland China come to Fuda for study and training. In future, Guangzhou Fuda Cancer Hospital will continue to keep up with the development of medical technology and provide better treatment for cancer patients.