What is the place of radiofrequency ablation in the integrated multidisciplinary treatment of lung cancer?

  Multidisciplinary comprehensive treatment of lung cancer refers to the planned and rational application of available multidisciplinary therapies to achieve the best therapeutic effect according to the patient’s physical and psychological condition, tumor site, pathological type, extent of invasion (clinical stage), and molecular biological alterations [39]. Current multidisciplinary treatments include surgical treatment, minimally invasive interventional treatment (radio-interventional, radiofrequency ablation, microwave ablation, argon helium knife, radioactive particles, photodynamic, etc.), radiotherapy, chemotherapy and molecular targeted therapy.  As a minimally invasive treatment method, radiofrequency ablation has the advantages of complete inactivation of tumor lesions in the treatment area, minimally invasive, well tolerated by patients, few intraoperative and postoperative complications, and the same organ can be repeatedly performed for many times.  According to the 7th edition of the lung cancer staging system, stage I lung cancer includes three combinations of TNM, all without lymph node metastasis. Among them, stage IA has T1aN0M0 lesions ≤2 cm; stage IA has T1bN0M0 lesions >2 and ≤3 cm; stage IB has T2aN0M0 with lesions >3 and ≤5 cm. stage II lung cancer includes six combinations of TNM. There were two combinations without lymph node metastasis, including T2bN0M0 lesions >5, ≤7 cm in stage IIA, and T3N0M0 lesions >7 cm in stage IIB, or lesions that had invaded the chest wall, diaphragm, septal nerve, mediastinal pleura, and pericardium. Four combinations of hilar lymph node metastases but no mediastinal lymph node metastases (N1) were present, including T1aN1M0 lesions ≤2 cm in stage IIA; T1bN1M0 lesions >2, ≤3 cm in stage IIA; T2aN1M0 lesions >3, ≤5 cm in stage IIA; and T2bN1M0 lesions >5, ≤7 cm in stage IIB. For stage I and II lung cancer, surgical resection in most patients is the preferred treatment. However, for patients who cannot tolerate surgery or are unwilling to undergo surgery, radiofrequency ablation can be the preferred treatment. Stage III lung cancer is locally advanced, with metastasis to mediastinal lymph nodes (N2) or supraclavicular lymph nodes (N3) or invasion of important structures such as mediastinum (T4). Only some patients with stage III lung cancer are suitable for surgical resection, but even if surgical treatment is performed, the outcome is still unsatisfactory. Currently, stage III lung cancer accounts for the majority of patients treated with radiofrequency ablation in clinical practice. Stage IV lung cancer has developed malignant pleural effusion, or malignant pericardial effusion, or contralateral lung metastasis or distant organ metastasis, and although radiofrequency ablation can play the role of reducing tumor load or improving symptoms, the overall efficacy is limited.  Except for stage I lung cancer where other adjuvant treatments may not be chosen after complete ablation of the primary lesion is achieved, the combination or sequential treatment of radiofrequency ablation with chemotherapy, radiotherapy or molecular targeted therapy for all other stages of lung cancer is more effective than any single method.  Lung is a good site for metastasis of many malignant tumors, especially double lung metastasis has been a difficult problem in clinical treatment, and the effects of radiotherapy, chemotherapy and surgery are not effective. Radiofrequency ablation can solve the problem of insensitivity of metastases to radiotherapy and chemotherapy because there are no resistant tumor cells in the treatment area; lung metastases are more invasive in surgery, and new lesions can easily appear after removal of metastases.