Surgical Assessment Intraoperative Staging

Criteria of Medical (in) operability

The risk of perioperative mortality and morbidity should be jointly assessed by the surgeon and the anaesthetist. In general, three important factors are taken into consideration.

1. Age: The perioperative risk associated with lung surgery is increased in patients aged more than 70 years, particularly for pneumonectomy, and especially right-side pneumonectomy. This increase is primarily due to increased comorbidity. For patients aged more than 80 years, it appears that the perioperative risks are even greater.

Scientific basis
Patients aged more than 70 years have an increased surgical risk during lung surgery. The perioperative mortality rate in this age group is 4%: 8% for pneumonectomy and 3% for more limited resection.[1] This increased risk in elderly patients is likely due to increased comorbidity. The surgical risk is increased particularly for right-side pneumonectomy: the perioperative mortality rate is 10.6% overall and 17.8% in patients aged more than 70 years, compared with rates for left-side pneumonectomy of 3.9% and 8.1%, respectively. In patients aged more than 80 years who undergo lung surgery (mostly lobectomy and more limited resection), perioperative mortality rates of 4-15% have been reported from relatively small studies.

2. Cardiovascular Assessment: Before surgery, cardiac disorders such as coronary disease, heart failure, valve disease and rhythm disorders should be detected through patient history, physical examination and ECG.
If lung surgery is planned for a patient with (signs of) heart disease, a cardiologist or an anaesthesiologist should assess the perioperative risk and advise on the perioperative protocol. Most centres would assess the ejection fraction by means of an Echocardiogram and for borderline patients a stress test may be useful.

3. Lung Function: The surgical risk is not considered increased if the forced expiratory volume in one second (FEV1) and the diffusion capacity (TLCO) are both > 80% and there is no unforeseen exertional dyspnoea.

If these criteria are not met, it is advised to calculate the predicted postoperative lung function using the calculation method (perfusion scan with left-right proportion and, for lobectomy, supplemented with the segment method).

If the operability of the patient is questioned based on the lung function assessment and/or the patient history (unforeseen exertional dyspnoea), an exertion test that includes determination of the maximum oxygen uptake (VO2max) is advisable.

Use of the flowchart is recommended for the evaluation of perioperative risk.

Flowchart for determining perioperative risk before lung surgery by means of lung function assessment. In the calculation method, the relative functional contribution of the left and right lung are calculated with the perfusion scan; for (bi)lobectomy, the functional contribution of the remaining lobe(s) of the affected lung is calculated by dividing the number of remaining segments by the total number of segments.

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General

Before surgery, it should be determined what maximum degree of parenchymal resection is prudent.
For patients with an increased surgical risk, alternatives such as limited resection or chemotherapy and/or radiotherapy should be weighed against the increased risk of surgery in a multidisciplinary consultation.

SURGICAL ASSESMENT

For operable patients with NSCLC in whom tumour growth is limited to one lobe, lobectomy is the treatment of choice. Intentionally curative radiotherapy is a good alternative if the surgical risk is determined to be (too) high.

Patients in whom lung function is so limited that lobectomy is not possible may be considered for segment resection (preferred) or wedge excision if complete resection using this method is possible.

In principle, if the lung tumour has spread from one lobe to another, a lobectomy plus a wedge resection of the other lobe should be performed. For central tumours, bilobectomy or pneumonectomy may be an option.

If a conventional lobectomy is not possible due to tumour growth up to or past the level of the bronchial ostium, a sleeve lobectomy is advisable because complete resection is possible with this technique even when lung function precludes pneumonectomy.

A sleeve resection of the pulmonary artery should be performed only if the patient cannot tolerate pneumonectomy due to lung function.

If there is tumour growth in the direction of the thoracic wall and it is questionable whether the tumour has spread through the parietal pleura, one should immediately opt for including the affected thoracic wall en bloc.

If during surgery it appears that the tumour has spread to the intrapericardially positioned portion of the pulmonary artery, it is often possible to conduct a pneumonectomy.

If during surgery it appears that the tumour has spread to or into the main carina, which precludes a conventional pneumonectomy, a sleeve lobectomy may be attempted. If this is not possible, it should be immediately ascertained whether a sleeve pneumonectomy can be performed on the right side. On the left side, a sleeve pneumonectomy can occur in 2 phases. Referral to a treatment centre is indicated.

If during surgery it appears that the tumour is growing into the vena cava superior, the adventitia of the aortic wall, the pericardium or the diaphragm, primary resection should not be ruled out a priori.

If during surgery it appears that the tumour is growing into the spinal column or into the left atrium substantially, it is seldom resectable.

If during surgery it appears that the tumour is growing into the pulmonary trunk or through the entire aortic wall or has led to pleuritis carcinomatosa, it is unresectable. This likely holds true also for spread to the oesophagus.

If during surgery it appears that there are more tumours present in one lobe, lobectomy is performed. If multiple tumours are present in different lobes (M1), primary resection is an option.

Requirements for intraoperative staging

If before surgery there is no known tissue diagnosis, intraoperative frozen section assessment of the tumour is recommended before proceeding to lung resection.

Intraoperative frozen section assessment is recommended if macroscopic findings of lymph nodes provide reason for it (indications of extranodal growth or bulky disease). This is applicable if the result of the assessment can influence the surgical procedure (lung resection and/or mediastinal lymph node dissection).

For central tumours, intraoperative frozen section assessment of the bronchial resection field is recommended, unless a positive result would have no influence on the surgical procedure.

Regardless of the location of the tumour, all intrapulmonary and hilar lymph nodes (N1 node stations 10, 11 and 12) should be removed en bloc with the resected section if possible.

To determine the status of mediastinal lymph nodes (N2 stations), at least the lymph node stations to which the tumour preferably drains should be systematically sampled during surgery.

Specifically, this implies for tumours of the
- right upper and middle lobe: node stations 2R, 4R and 7;
- right lower lobe: node stations 4R, 7, 8 and 9;
- left upper lobe: node stations 5, 6 and 7;
- left lower lobe: node stations 7, 8 and 9.

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Requirements for surgical documentation

Following an operation for NSCLC, the surgical documentation should contain:
- surgical approach (thoracotomy, sternotomy, etc);
- tumour location, size, extent and distance from the main carina;
- presence or absence of satellite lesions and metastases in other lobes;
- lymph node stations (extranodal growth) and surgical technique used to evaluate mediastinal lymph nodes;
- presence and characteristics of pleural effusion; pleural lavage (duration and method), if applicable;
- result of frozen section assessment, if performed;
- distance between the tumour and the resection field, particularly the bronchial resection field;
- radicality of the resection (R0, R1 or R2);
- placement of clips to demarcate the resection field, if applicable;
- perioperative consultation with other specialists;
- complications, if applicable;
- conclusion: procedure performed and intraoperative staging.

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