With the rapid development of imaging technology, percutaneous image-guided local ablation technology, as a kind of minimally invasive tumor treatment method, has been developing rapidly at home and abroad in recent years and has gradually become one of the common means of minimally invasive tumor treatment.
1.What is microwave ablation therapy?
The principle of microwave ablation is actually the same as the principle of microwave oven, through the thermal effect of microwave, the local tumor tissue of lung reaches a temperature of 70℃ or above within a few minutes, causing coagulative necrosis of the tumor tissue, while the surrounding tissues are rarely or not damaged. The purpose of “burning” the tumor cells.
In layman’s terms, a special microwave ablation needle of only 2mm is inserted into the tumor under the guidance of CT and other imaging technologies, and the CT scan clearly “hits the target center” and then begins to heat and ablate, completely burning an egg-sized tumor to death in 5-10 minutes.
2.Indications of microwave ablation for lung cancer.
(1) Indications for local radical treatment
a.Primary peripheral lung cancer: patients cannot tolerate surgery or cannot be surgically removed or recur after not receiving surgery or other local treatment (such as modality radiotherapy), and the maximum diameter of the tumor is ≤87.5px.
b. Metastatic peripheral lung cancer: the number of lesions in one lung is ≤ 3, and the maximum diameter of tumor is ≤ 87.5px.
(2) Indications for palliative tumor load reduction or symptom relief
The purpose of treatment is to minimize the tumor load and alleviate the symptoms caused by tumor.
(3) Contraindications of microwave ablation for lung cancer.
a.The lesion is ≤25px from the lung door, the treatment target skin distance is <50px, and there is no effective puncture channel.
b. Infectious and radiological inflammation around the lesion is not well controlled. Those with malignant pleural effusion ipsilateral to the ablation lesion that is not well controlled.
c.Patients with severe bleeding tendency, platelets less than 50×109/L and serious disorders of coagulation system (prothrombin time >18S, prothrombin activity <40%).
d. Patients with severe hepatic, renal, cardiac, pulmonary and cerebral insufficiency, severe anemia, dehydration and serious disorders of nutrient metabolism that cannot be corrected or improved within a short period of time, severe systemic infections and high fever (>38.5℃).
e. Advanced tumor patients with KPS score of 70 and psychiatric patients are not suitable for microwave ablation treatment.
(4) What are the complications of microwave ablation for lung cancer?
Pneumothorax is the most common complication, with an incidence of about 20%, but only 5% of them need to be treated. Others, such as infection and bleeding, have a lower incidence. The incidence of thermal injury to adjacent organs and burns at the puncture site is extremely low.
3.What are the advantages and disadvantages of microwave ablation for lung cancer treatment?
(1) Advantages
a. Definite curative effect. For small tumors (below 75px) with good location, local ablation can achieve the effect of surgical resection. If the doctor is skilled in operation, even large tumors or tumors in dangerous locations can achieve complete necrosis, which is incomparable to traditional vascular interventions and other treatment methods.
b. Minor trauma. Local ablation can achieve the treatment purpose only with the help of a small needle eye of 1-2 mm, which does not require a large incision of about 20 cm for surgical operation.
c. Safer. Although local ablation also has certain risks, compared with surgical excision, the complication rate is lower, less severe and mostly easy to handle.
d. Simple. Surgical operation usually takes more than 2 hours, while local ablation of tumor can be done in about 10 minutes.
e. Quick recovery. If it goes well, most of the surgical procedures will take 3 days to get off the ground, 8 days to remove the stitches, and 10 days to be discharged from the hospital, while local ablation can be done after the surgery.
f. Higher quality of life. Surgical resection often leaves long-term complications or sequelae, and radiotherapy has strong toxic reactions, while similar sequelae of local ablation rarely occur.
g. Repeatable. Vascular interventions can be performed several times, but the efficacy is much inferior to local ablation; surgical procedures have the highest efficacy, but are more damaging and difficult to perform several times. The efficacy of local ablation is close to that of surgical resection, but the scope of tissue damage is small, so it can be repeated for many times for recurrent lesions.
(2) Disadvantages.
a. Although the requirements of local ablation for liver function and other indicators are relatively low compared with surgery, critical condition and poor general health status are also the main contraindications of local ablation treatment.
b. The efficacy and safety are closely related to the size and location of the tumor. From the existing research data, the larger the tumor is, the worse the ablation treatment effect is; if the tumor is close to other important organs, the treatment effect will be greatly reduced due to the cast of the mouse.
c. Radiofrequency ablation treatment involves many disciplines such as imaging, oncology, interventional radiology, etc. The requirements for surgeons are very high.