The incidence of lung cancer in the elderly is almost 10 times higher than that of young people, Wang Weiwei, Department of Thoracic Surgery, Yunnan Cancer Hospital. The special physical conditions of elderly patients, such as functional failure, slow movement and more complications, make the choice of treatment modality very difficult. Clinically, non-standard and more conservative treatment modalities are often used because of the fear that elderly patients cannot tolerate invasive surgery and more toxic chemotherapy.
This misperception often prevents optimal treatment outcomes for older patients. Old age is not a contraindication, but rather factors such as cardiopulmonary function and associated complications are more important in assessing patients for surgical treatment than age. Therefore, an individual and thorough evaluation of elderly patients is necessary to maximize the benefit of their treatment.
1. Preoperative evaluation and preparation
Surgery is considered to be the best option for treating early-stage tumors. For relatively healthy elderly patients who can tolerate surgery, surgery can significantly prolong survival and improve quality of life, so proper preoperative evaluation and preparation are especially critical.
In a series of studies, the postoperative complication and mortality rates of elderly surgical candidates selected after careful evaluation were not significantly different from those of younger patients, and the quality of life of elderly patients was not significantly different from that of younger patients in the first year after surgery. These results suggest that careful preoperative screening and evaluation of elderly lung cancer patients can effectively reduce postoperative complication rates and mortality.
1.1 Tumor staging
Tumor stage is the most important predictor of postoperative survival, which can help to clarify the disease as well as determine the treatment plan. A clear diagnosis and tumor staging is necessary for patients of any age and is an important factor in determining whether a patient will benefit from surgery. Clinical and pathologic staging can be determined by the modified TNM staging system, blood tests and renal function tests.
Patients undergo lung and abdominal CT and positron emission tomography (PET) scans. If the PET scan is positive (N2 or M1), a tissue biopsy will be performed for further confirmation. The location of all potentially positive lymph nodes should be determined. If possible, a transbronchoscopic biopsy or percutaneous subpulmonary puncture biopsy should also be performed, which not only facilitates the procedure but also reduces the need for unnecessary general anesthesia or open-heart surgery in patients with metastatic tumors.
1.2 Assessment of cardiopulmonary function
Pulmonary function is generally assessed by arterial blood gas analysis, spirometry, and pulmonary carbon monoxide diffusion. Patients who will undergo lobectomy should meet the requirements of an arterial partial pressure of oxygen ≥ 65 mmHg (1 mmHg = 0.1333 kPa), an arterial partial pressure of carbon dioxide ≤ 45 mmHg, and an expected maximum postoperative expiratory volume of ≥ 0.8 L in 1 min.
For the elderly aged 70 years or older, a preoperative maximum expiratory volume of ≤55% or an arterial partial pressure of oxygen <60 mmHg will increase postoperative mortality. When the maximum expiratory volume is less than 80%, lung airflow gamma radiography and endurance testing are performed. Postoperative mortality and long-term survival in elderly patients with maximal expiratory volume greater than 70% are comparable to those of younger patients.
Pulmonary carbon monoxide dispersion testing is an extremely reliable and inexpensive test of lung function, and the expected postoperative carbon monoxide dispersion is an important predictor of postoperative mortality, overall complication probability, and can be obtained by multiplying the raw observed values by the percentage of lung parenchyma lost (15% right upper lobe, 10% right middle lobe, 25% right lower lobe, 25% left upper lobe, 25% left lower lobe).
As lung cancer patients age, they often have a delayed response to hypoxia and hypercapnia, decreased lung elasticity, and reduced forceful expiratory volume, so these pulmonary function assessments, which apply to all surgical candidates, need to be more detailed and rigorous in older adults.
While assessing pulmonary function, it should not be overlooked that many older adults suffer from heart disease and should therefore be examined for a history of heart disease, including localized myocardial ischemia, congestive heart failure, arrhythmias, and valvular heart disease. The American College of Cardiology and the American Heart Association have published guidelines for cardiac screening prior to noncardiac surgery, which can be followed for assessment of cardiac function and appropriate measures.
1.3 Nutritional status
Surgery is an invasive intervention that increases the risk of infection and the need for energy in elderly patients whose physical function and immune system are not as strong as those of younger people. Because surgery increases the energy expenditure of the body, and because cancer treatment often brings adverse nutritional effects to the elderly, such as nausea, anorexia, premature satiety, vomiting, and fatigue, patients usually do not receive an adequate nutritional supply as a result.
The nutritional status before surgery is determined by body mass index, serum albumin level (<3.0 g/L), and history of weight loss. Gupta et al. studied the relationship between pre-treatment serum albumin levels and survival in cancer patients using online medical literature analysis and information from the MEDLINE database (1995-2010), and concluded that preoperative albumin levels were positively associated with survival.
Similarly Tewari et al. studied 642 patients with non-small cell lung cancer and divided them into two groups, malnourished and well-nourished, using the three parameters mentioned above, and found that the malnourished group had a significantly higher rate of postoperative gastrointestinal complications and a significantly lower long-term survival rate than the control group (36 months: 58 months). It can be seen that improving the adverse effects of treatment and maintaining adequate nutritional supply for the elderly are necessary for the prolongation of postoperative survival and quality of life.
1.4 Others
A number of tests have been performed to find the physiological limits of whether a patient can withstand surgery, predict the probability of postoperative mortality and complications, and postoperative survival, but the predictions are usually vague and generally unsatisfactory. Comprehensive geriatric assessment (CGA) is a clinical test used to comprehensively assess the signs of aging in patients, and it tests the patient’s physical ability, perceptual ability, nutritional status, psychological status, functional status, and medical history.
CGA has been considered an important tool for risk classification of elderly cancer patients, however, its drawbacks are also obvious: it is time-consuming, costly, and lacks clear steps to interpret and apply the test information. The coverage of the test should not be too large, as this can significantly reduce the predictive power, and the operation should be as easy and reproducible as possible.
The eastern cooperative oncology group (ECOG) index, which is used to assess the physical status of patients, classifies patients into six levels from 0 to 5, with PS ≥ 2 representing people with varying degrees of physical activity limitation, which is often used as a physiological cutoff for receiving platinum-based chemotherapy. The advantages of the ECOG index are that it is a more accurate prognostic index for cancer treatment, especially for chemotherapy, and it is a more ideal evaluation index in clinical practice because of its low variability and easy operation.
At the same time, neoadjuvant chemotherapy has also been given great expectations. Neoadjuvant chemotherapy differs from traditional adjuvant chemotherapy in the period of receiving chemotherapy, and it has the advantages of eliminating micrometastases, reducing tumor stage, and reducing the stress response during the perioperative period. However, many studies have found no significant difference in response rate between neoadjuvant and adjuvant chemotherapy, and the effect of neoadjuvant chemotherapy on improving survival is poor, with only about 5% improvement in survival rate.
In addition, one study found that the incidence of postoperative comorbidities was three times higher in older adults receiving neoadjuvant chemotherapy than in the control group. Chemotherapy is a shock in itself for the frail elderly, so neoadjuvant chemotherapy should be used with caution in the elderly with lung cancer.
In addition, smoking cessation prior to surgery is a necessary preparation. According to previous literature, patients should quit smoking at least 6 weeks before surgery to avoid low bronchial mucus secretion due to bronchial mucosa regeneration, and to reduce the risk of postoperative complications.
2. Surgery
The choice of the patient’s surgical procedure should be based on the following principles.
① The expected postoperative survival of the patient must exceed the expected survival without resection (generally 6-7 months);
②The expected long-term postoperative survival must be long enough to allow the patient sufficient time to recover from the surgery;
(iii) The postoperative mortality rate should be as low as possible to ensure the utility of the surgery;
④There should not be excessive postoperative complications such that the quality of life is reduced. The postoperative quality of life is particularly important in the elderly because of their limited life expectancy. There are many reports in the literature about the high morbidity and mortality of complications associated with total pneumonectomy. Therefore, total pneumonectomy, especially of the right lung, is generally not recommended for the elderly. Two procedures that are more frequently performed in elderly patients are listed below.
2.1 Partial resection
Local surgical resections such as lobectomy and wedge resection are often performed in elderly patients with lung cancer. 264 patients with stage I and II lung cancer were treated with lobectomy (203) or local resection (61) by Gonzalez-Aragoneses et al. The 5-year overall survival rates were 54% and 55%, respectively, suggesting that limited resection has adequate therapeutic utility in elderly patients with early stage lung cancer. Kates et al.
In an analysis of surveillance, epidemiology, and prognostic databases, Kates et al. showed that the overall survival of older adults over 70 years of age who underwent limited resection was similar to that of lobectomy (HR=0.99, 95% CI 0.74 to 1.33). However, because the long-term utility of limited resection and stabilization of recurrence rates is less controversial than standard lobectomy, a conservative approach of local resection is usually recommended clinically for patients with cardiopulmonary failure, high surgical risk, and multiple comorbidities, but its utility needs further study to determine.
2.2 Television-assisted thoracoscopic surgery
In a retrospective study of 164 patients with similar preoperative characteristics, Cattaneo et al. In a retrospective study of 164 patients with similar preoperative characteristics, Cattaneo et al. reported that patients who underwent VATS (50%) had a lower incidence of postoperative complications (28% versus 45%, P=0.04), a lower severity of complications, a shorter mean length of stay (5d versus 6d, P<0.001), and a (03.6%) reduction in perioperative mortality than patients who underwent conventional open-heart surgery. For stage I patients, several trials have reported higher 5-year survival rates with VATS, and Berry et al. suggested that thoracoscopic surgery would be the most appropriate procedure for these patients if the technology is met. However, VATS is only indicated for patients with early-stage lung cancer and requires a high level of surgeon expertise. As surgeons become more proficient in television-assisted thoracoscopic lobectomy or total pneumonectomy, operative times are expected to decrease. In the future, VATS will be more widely used.
3. Conclusion
Surgical resection of tumors is a more effective treatment modality for lung cancer. However, the key to the selection of surgical modality is to find the individualized optimal treatment outcome, so it is very important to conduct a detailed and in-depth evaluation of factors that have a high ability to predict postoperative survival, mortality, and complications.