Anatomic pneumonectomy is the main treatment for early to mid-stage lung cancer and is currently an important clinical cure for lung cancer. Lung cancer surgery is divided into complete resection, incomplete resection and indeterminate resection. We should strive for complete resection to achieve complete removal of tumor, reduce metastasis and recurrence, and perform accurate pathological TNM staging and strive to clarify molecular pathological staging to guide comprehensive postoperative treatment.

Surgical anatomy of the bronchial and pulmonary systemsThe trachea is the airway that connects the pharynx to the bronchopulmonary system. The trachea is approximately 10 to 13 cm in length and begins at the inferior border of the cricoid cartilage (approximately the inferior border of the flat 6th cervical vertebra) to the ramus (approximately the level of the 4th thoracic vertebra), usually with 18 to 22 cartilaginous rings. The blood supply to the trachea is segmental, with the upper part coming mainly from branches of the inferior thyroid artery and the lower part from branches of the bronchial artery. Therefore, the trachea should not be freed too much, as this may affect the blood supply and healing of the preserved trachea.
The trachea is divided into the left and right main bronchi at the level of the bulge. The angle between the main bronchus and the trachea is flatter on the right side than on the left side, so it is easier for the tracheal foreign body to enter the right main bronchus by accidental aspiration. The right main bronchus is further divided into the right upper lobe bronchus and the middle section bronchus. The middle segment bronchus is further divided into middle lobe and lower lobe bronchus. The right upper lobe bronchus is further divided into three segments: apical, posterior, and anterior bronchus. The middle lobe bronchus is further divided into medial and lateral bronchial segments. The lower lobe bronchi emit dorsal segmental bronchi and a total of 4 basal segmental bronchi, medial, anterior, lateral, and posterior. The length of the left main bronchus is about 4.5-5 cm, and it is divided into upper and lower lobe bronchi downward. The left upper lobe bronchus is subdivided into the intrinsic upper lobe bronchus and the lingual lobe bronchus. The former is usually divided into anterior and post-apical bronchi, while the latter is divided into supralingual and inferior lingual bronchi. The lower lobe bronchi give off dorsal segments and anterior internal, external, and posterior basal segment bronchi. The right lung includes horizontal and oblique fissures, which are divided into 3 lobes and 10 segments, accounting for 55 respiratory functions, while the left lung is divided into 2 lobes and 8 segments by oblique fissures, accounting for 45 respiratory functions.
The blood flow of the lungs includes the pulmonary circulatory system of the pulmonary arteries and the body circulatory system of the bronchial vessels. The bronchial arteries emanate mainly from the descending aorta or intercostal arteries and travel with the bronchi, eventually forming a network of capillaries supplying the bronchi in the bronchial epithelium and submucosa. The venous blood mainly flows into the pulmonary veins, and to a lesser extent into the bronchial veins, and then into the odd and semi-odd veins. The main pulmonary artery trunk originates from the right ventricle and travels upward to the left, dividing into the left and right pulmonary artery trunks under the aortic arch. The right pulmonary artery trunk is longer than the left pulmonary artery trunk, but it begins to branch earlier than the left. The pulmonary artery is usually accompanied by the corresponding bronchus. Both the right and left pulmonary veins include the upper and lower pulmonary veins, which converge into the left atrium, respectively. The right middle pulmonary vein usually co-trunks with the right upper pulmonary vein to form the upper pulmonary vein.

Indications for lung cancer surgeryFrom the perspective of lung cancer alone, the absolute indications for lung cancer surgery, i.e., the current consensus indications for surgery, are lesions in the T1 to 3N0 to 1M0 stage; the relative indications for lung cancer, i.e., the current majority accepted indications for surgery, are lesions in the partial T4N0 to 1M0 stage; the more controversial indications for lung cancer surgery are lesions in the T1 to 3N2M0 stage; and the exploratory indications for lung cancer surgery include Partially isolated metastatic lesions of stage T1 to 3N0 to 1M1.

Contraindications to lung cancer surgery

The recognized contraindications to surgery for lung cancer are: (1) lung cancer stage beyond the indication for surgery; (2) poor systemic status with a Canovske score of less than 60: it is recommended that the score be considered in conjunction with the ECOG score in line with international practice; (3) acute myocardial infarction within 6 weeks; (4) severe ventricular arrhythmias or uncontrolled heart failure; (5) cardiopulmonary function that does not meet the intended surgical (6) patients over 75 years of age with carotid stenosis greater than 50 and under 75 years of age with carotid stenosis greater than 70; (7) patients over 80 years of age with lesions requiring total pneumonectomy; (8) severe, uncontrolled concomitant disease that continues to impair the patient’s physical and psychological function; and (9) patients who refuse surgery.

Concept of complete resection for lung cancerThe NCCN guidelines specifically define complete resection of lung cancer as: (1) complete resection of lung cancer in which all margins are included, including all bronchial or (and) pulmonary angioplasty. (1) all margins, including bronchi, arteries, veins, peribronchial tissue, and tissue adjacent to the tumor, are negative; (2) systemic or lobar systemic lymph node dissection must include six groups of lymph nodes, three of which are from intrapulmonary (lobar, interlobular, or segmental) and hilar lymph nodes, and three from mediastinal lymph nodes, including subserosal lymph nodes; (3) separately resected mediastinal lymph nodes or marginal lymph nodes of the resected lobe must not be extra-nodal. (4) the highest lymph node must be resected and be microscopically negative. Only if all 4 conditions are met can the resection be classified as complete; otherwise, the resection is incomplete or indeterminate.

Lymph node dissection for lung cancer

Mediastinal/portal/segmental lymph node dissection is an integral part of complete lung cancer resection, and lobectomy or total lung resection with systematic mediastinal lymph node dissection is considered the standard procedure for lung cancer surgery. However, recent high-level evidence-based evidence suggests that partial lobectomy with lobe-specific lymph node dissection has a long-term survival rate no worse than the standard procedure and may also be an option for some early-stage lung cancers.
The current internationally accepted atlas of draining lymph nodes in lung cancer is the 2009 Lymph Node Atlas of the International Union for the Study of Lung Cancer. Mediastinal lymph nodes include 9 groups of lymph nodes from stations 1 to 9, and hilar lymph nodes include all groups of lymph nodes up to station 10. The standard mediastinal lymph node dissection requires complete removal of the mediastinal lymph nodes and their surrounding fatty tissue, also known as complete mediastinal lymph node dissection.

Overview of lung cancer surgeryLung cancer surgery can be divided into: complete resection (radical resection) and incomplete resection (palliative resection), as well as biopsy surgery mainly for diagnostic purposes, according to the degree of complete tumor removal; and divided into: wedge resection (partial resection), segmental resection, lobectomy, compound lobectomy (removal of more than 1 lobe containing the tumor), total lung resection, pneumonectomy with tracheal, bronchial and/or pulmonary angioplasty, and extended lung cancer resection with combined resection of tumor-invaded organ tissue. The size of the incision and trauma can be divided into: conventional open-heart surgery, small-incision open-heart surgery and minimally invasive thoracoscopic surgery. The term “lung cancer resection” generally refers to complete resection surgery.
The standard anesthesia method for lung cancer resection is double-lumen tracheal intubation with the lung on the operated side not ventilated. The patient is placed in the healthy-side position. The incision is usually made through a posterior lateral incision into the chest cavity through the 5th or 6th intercostal space; the thoracoscopic incision varies according to the patient’s and surgeon’s preference, usually through the 4th or 5th intercostal space for a single-port thoracoscope, with more variation for a two/three-port thoracoscope. The surgical keys to lobectomy are ligation and dissection of the arterial branches and pulmonary veins of the lobe, dissection and closure of the bronchi of the lobe, and dissection of the interlobular lung fissures. For lobectomy, surgery starting with dissection of the lung fissures is the usual choice. Sleeve lobectomy is usually considered when the central lung cancer tumor encroaches on the lobar bronchial opening, when there is tumor remaining at the bronchial margin of the lobectomy or when it is too close to the tumor. If the bronchial margins of the sleeve lobectomy are still inadequate, then total pneumonectomy needs to be considered. The most common reason for total pneumonectomy is not a positive bronchial margin, but rather invasion of the pulmonary artery. Clinically, total pneumonectomy is usually performed on the left side. Right-sided total pneumonectomy is rarely performed because of the high level of pulmonary impairment, the low quality of life of the patient and the poor tolerance of postoperative adjuvant therapy. Complex lobectomies are mainly middle and lower lobectomies and upper and middle lobectomies of the right lung. Middle and lower lobectomy of the right lung is commonly performed because the middle lobe of the right lung invades the middle lobe bronchial opening and the dorsal segment of the lower lobe of the right lung invades the segmental bronchial opening, and middle and lower lobectomy is usually required to ensure negative bronchial margins. Since the middle lobe pulmonary veins of the right lung usually merge into the upper lobe pulmonary veins to form the right upper pulmonary vein, either upper or middle lobe carcinoma of the right lung may require upper or middle lobectomy if it invades the confluence of the upper and middle lobe veins of the right upper pulmonary vein. The anatomic partial lobectomy includes segmental, combined segmental, and combined subsegmental lung resections, which are more delicate and complex, and 3D reconstruction software can help the surgeon complete the procedure more accurately and smoothly.

Surgical complications of lung cancer

The complication rate after lung cancer surgery is about 8 to 35. The most common complications are respiratory and cardiovascular complications, while the more unique complications of lung resection include postoperative air leak in the lung section and bronchopleural fistula.
(1) Respiratory complications: Most commonly seen in patients with preoperative chronic bronchitis. The common complication is poor pulmonary reopening on the operated side, including atelectasis and obstructive emphysema. The main cause is the blockage of bronchi by sputum. In some patients, due to early anesthetic intubation, intraoperative rub injury, and recurrent pulmonary atrophy and reopening, the lung secretions on the affected side increase, and due to pain, vagal nerve bronchial branch injury, and inadequate ventilation, the patient is unable to cough up sputum and sputum clots form. The clinical manifestations are decreased breath sounds in the affected lung, shortness of breath, decreased oxygen saturation, and fever and other symptoms of infection. In severe cases, bronchoscopic aspiration is required, and in rare patients, tracheotomy is required.
(2) Pulmonary section air leak: Mostly seen in patients with preoperative combined emphysema and pulmonary aspergillosis, but also occurs in some patients with partial lobectomy due to large lung trauma, mainly due to air leak from the lung section during dissection of the lung fissure. The clinical manifestation is a prolonged and continuous escape of air bubbles from the chest drainage tube. The diagnosis should exclude bronchopleural fistula, and the key to treatment is adequate drainage to ensure good reopening of the remaining lung and prevention of infection. In most patients, air leakage from the section gradually decreases with postoperative tissue adhesions.
(3) Bronchopleural fistula: Bronchopleural fistula refers to a series of clinical symptoms and signs caused by poor healing of the bronchial dissection and communication of the bronchial stump with the pleural cavity.
The incidence of bronchopleural fistula was 1.6, and the incidence reported in a large group of domestic cases was about 1. Clinical manifestations include cough, sputum, shortness of breath, and fever. Signs and chest radiographs mainly showed encapsulated liquid pneumothorax, abscess chest changes, and some patients had aspiration pneumonia changes. The cough and sputum are suggestive. Initially, the sputum is significantly increased, thinner and light red pleural effusion-like, further it can appear as pus sputum, especially when there is obvious pus chest. However, the most direct diagnostic modality is tracheoscopy. Treatment is based on chest drainage, with drains placed around the fistula as much as possible. For early postoperative occurrences, surgical repair may be attempted; otherwise, surgical repair is very difficult and most can only be drained. Placement of a tracheal stent to temporarily close the fistula has been reported. Closure of the fistula with medical bioprotein gel has been reported in cases after the inflammation has been limited.

Advances in the surgical treatment of lung cancer

(1) Role of television thoracoscopic surgery in the surgical treatment of lung cancer: Television thoracoscopic surgery is one of the greatest advances and developments in thoracic surgical techniques in the last 20 years. The role of TV thoracoscopic surgery in lung cancer surgical treatment is gaining more and more attention and is one of the future directions of lung cancer surgical treatment. There are many different opinions regarding the indications for the procedure, which are related to how early the procedure was performed in the medical institution and the preference and proficiency of the surgeon. However, as stated in the NCCN guidelines, the premise of thoracoscopic surgery as the surgical procedure of choice for lung cancer is to conform to the principles of lung cancer surgery, i.e., to ensure the safety of the procedure without compromising the completeness of surgical resection.
(2) Choice of surgical approach for early stage peripheral lung cancer: lobectomy has long been considered by most thoracic surgeons as the standard procedure for surgical resection of stage I non-small cell lung cancer, while recent clinical evidence supports that lung segmental resection or wedge resection may be a better surgical resection approach for peripheral stage I non-small cell lung cancer up to 2 cm in diameter, especially for purely ground glass nodules. With the increasing number of retrospective reports, the use of partial lobectomy (segmental or wedge resection) for peripheral early-stage lung cancer with a predominantly ground-glass component is becoming a consensus in thoracic surgery. The recent results of the large randomized controlled trial JCOG0802 showed that segmental resection has better 5-year survival than lobectomy and better preservation of lung function for peripheral non-small cell lung cancer with a solid component >50 and a tumor diameter ≤2 cm. As more studies like this are disclosed, partial lobectomy may become the standard procedure for this type of lung cancer.