Metastatic tumors of the lungs



OVERVIEW

Definition.

Metastatic tumors of the lungs are secondary tumors that develop from malignant tumors of other tissues or organs that metastasize to the lungs.

Because tumors that can metastasize are generally malignant, pulmonary metastatic tumors can be classified as a specific type of lung malignancy.

Staging and Classification

According to the different tissue sources of the tumor, it can be divided into lung metastatic carcinoma, lung metastatic sarcoma and other types of lung metastatic malignant tumors.

Lung metastatic carcinoma

It is the most common type of lung metastatic tumor and is formed when epithelioid cells from other tissues and organs undergo malignant transformation and metastasize to the lungs.

The most common type of metastatic lung tumor is caused by breast cancer. Other common tumors include colorectal cancer, thyroid cancer, liver cancer, and so on.

Lung Metastatic Sarcoma

It is formed when the mesenchymal tissues of other organs or body parts undergo malignant changes and metastasize to the lungs.

Common ones include metastatic lung tumors caused by osteosarcoma, chondrosarcoma and liposarcoma.

Other types

Less common, including various malignant tumors of germinal origin, malignant mother cell tumors and other metastatic tumors of the lung.

Commonly, such as malignant teratoma, nephroblastoma and other lung metastatic tumors.

Morbidity

It varies slightly according to the type of malignant tumor, in which malignant tumors occurring in the chest and abdomen are more likely to metastasize to the lungs, while malignant tumors occurring in the central nervous system metastasize to the lungs more rarely.

The statistics presented by different statistical data vary, and the reported incidence of lung metastatic tumors is lower than the actual situation in some regions with poorer medical conditions due to limited examination means.

The lung is considered to be the most common site of metastasis of malignant tumors, and the probability of lung metastasis in patients with malignant tumors is about 40% to 50%.

In particular, approximately 30% of all autopsies of patients who died of malignant tumors developed metastatic lung tumors.

Etiology

Causes of disease

The direct cause is the metastasis of malignant tumors from other tissues or organs to the lungs.

The underlying cause is the action of various carcinogenic factors on the human body, leading to genetic mutation of cells and eventual malignant transformation.

Common clinical carcinogenic factors include the following:

Genetic defects

Some patients have some degree of genetic defects, such as reduced activity of oncogenes like Rb and APC. This group of people will have a higher risk of developing malignant tumors in the future than normal people.

Tobacco and Alcohol Consumption

Tobacco burning or alcohol metabolism process will produce a variety of harmful substances, these substances easily lead to cell damage. The risk of mutation and eventual malignancy is greatly increased when the cells are repairing the damage.

Chemical substances

Including nitrosamines, polycyclic aromatic hydrocarbons and so on. These substances are highly fat-soluble and can easily penetrate the cell membrane and act on the genetic material in the cell nucleus, ultimately leading to the transformation of the cell into a cancerous cell due to genetic mutation.

Ionizing rays

Includes X-rays, gamma rays, etc. Ionizing radiation has high energy and can cause damage to the DNA strand of human cells, eventually leading to malignant transformation of cells.

Others

Staying up late at night and having bad moods can cause the endocrine system to become dysfunctional, which in turn leads to a decrease in the body’s resistance. Lymphocytes cannot completely remove the mutated cells, at which time the risk of cancer will increase accordingly.

In addition, malnutrition, AIDS, taking hormonal drugs and other factors may also increase the risk of malignant tumors, which will further lead to a higher risk of lung metastatic tumors.

High risk factors

Patients with the following risk factors are at high risk for this disease. Regular checkups are needed to prevent the development of this disease.

Patients who have been diagnosed or are highly suspected of having a malignant tumor outside the lungs.

Patients who have not yet been found or diagnosed with any malignant tumor, but have the following conditions:

pathogenesis

Metastasis of tumor cells from other tissues and organs to the lungs is a very complex process that may involve multiple mechanisms, the exact mechanisms of which are not yet fully understood.

It may be related to further mutations in tumor cells at BCL-2, MYC, and other gene loci, which lead to a decrease in cell-to-cell adhesion and thus gain the ability to metastasize to other sites.

The common ways for tumor cells to metastasize to the lungs include trans-lymphatic metastasis, trans-bloodstream metastasis, and implantation metastasis, etc., which then colonize the lungs and continue to divide, and ultimately form lung metastatic tumors.

Symptoms

Main symptoms

Some patients may have no obvious clinical symptoms. When the tumor is large in size, patients may experience respiratory symptoms such as cough, sputum, wheezing, chest pain and hemoptysis.

Cough

It is the most common symptom in patients with metastatic lung tumor, mostly irritating dry cough.

It is usually caused by the tumor tissue stimulating the nerve endings of bronchial mucosa.

Coughing up sputum

It is usually caused by the increase of bronchial secretion due to the stimulation of bronchial mucosa by tumor tissues, and it is mostly white sputum.

If the tumor tissue is secondary to infection or bleeding, the patient may show yellow sputum or bloody sputum.

Wheezing

When the tumor mass is relatively large or has multiple metastases in the lungs, causing pressure on the airways, or even causing pulmonary atelectasis, the patient will have obvious symptoms of stridor.

If the tumor tissue invades into the pleural cavity, causing the patient to develop a large amount of pleural effusion, the patient may have symptoms of stridor in addition to panic.

Chest pain

It is usually caused by further invasion of the tumor into the pleura, ribs, intercostal nerves and other structures.

Mild patients show intermittent pain. Severe patients may have persistent severe pain, and the degree of pain does not change with respiration.

Hemoptysis

It is usually caused by tumor necrosis and bleeding.

Mild patients may show blood in sputum, and severe patients may even hematemesis a large amount of fresh blood, or even asphyxia, hemorrhagic shock and other life-threatening complications.

Complications

The common complications of this disease are mainly caused by the further destruction of lung tissue by the tumor. The common ones include pneumothorax, lung infection, hemoptysis, pleural effusion and malignant disease.

Pneumothorax

Pneumothorax is caused by the invasion of tumor tissue into the visceral pleura, resulting in rupture of the visceral pleura.

Mild patients only show a small amount of pneumothorax in the pleural cavity, with no obvious clinical symptoms or only mild wheezing.

Severe patients may even develop tension pneumothorax, with severe chest pain, dyspnea and other symptoms, which may be life-threatening.

Lung infection

It is usually caused by the necrosis of tumor tissues, and may also be caused by the obstruction of bronchial tubes leading to pulmonary atelectasis.

In mild cases, it may manifest as obstructive pneumonia. In severe cases, severe infections such as lung abscess and pyothorax may occur.

Common clinical symptoms include fever, coughing up pus and sputum, and chest pain.

Hemoptysis

Generally caused by tumor tissue invading blood vessels such as bronchial arteries and small pulmonary arteries. It can also be caused by liquefaction and necrosis of the tumor.

In severe cases, blood reflux into the bronchial tubes may cause asphyxiation, which is life-threatening.

Pleural effusion

It can be caused by further metastasis of tumor cells to the pleural cavity, or caused by hypoproteinemia due to rapid growth of the tumor.

When pleural effusion compresses the heart and lungs, it can lead to panic, dyspnea, chest pain and other symptoms.

Malignant Disease

If the tumor further progresses and metastasizes to various organs in the body, while consuming a large amount of nutrients, it will lead to malignant disease in the patient.

The patient may suffer from anemia, hypoproteinemia, electrolyte disorders, and other serious conditions, often resulting in death.

Consultation

Department of Medicine

Oncology

If the patient has been diagnosed with malignant tumors of other organs and at the same time develops chest pain, cough, sputum, wheezing, panic, etc., it is recommended that the patient seek medical treatment promptly.

Thoracic Surgery

Patients are recommended to consult the Department of Thoracic Surgery for timely treatment if surgical resection can be attempted after a definitive diagnosis of metastatic lung tumor has been made by a doctor’s evaluation.

Emergency Department

If symptoms such as severe chest pain, dyspnea, massive hemoptysis, etc. suddenly appear, it is recommended to consult the Emergency Department in a timely manner.

Preparation

Consultation: Registration, Preparation of Information, Frequently Asked Questions

Tips for Medical Treatment: Registration, Preparation of Documents, Frequently Asked Questions

There are no special precautions. Patients are advised to rest before the consultation and to stop taking painkillers and other medications to avoid masking the symptoms.

It is recommended not to wear clothing with metal material, do not wear jewelry, remove dentures in advance, etc., to facilitate the relevant impact of the examination.

Family members are recommended to accompany you to the clinic.

Preparation Checklist

Pay particular attention to the time of onset of symptoms, special manifestations, etc.

Is there chest pain, what is the nature of the pain, how long does it last, is it related to breathing?

Is there a cough, how often does it occur, is it accompanied by sputum, and what is the nature of the sputum?

Is there wheezing, how long does it last, and is it accompanied by bruising of the lips and nails?

Is there hemoptysis, what is the amount of hemoptysis, and what is the color or character of the blood?

Is there any previous diagnosis or high suspicion of malignant tumors in other tissues or organs?

Do you have bad habits such as smoking and drinking?

Do you often have irregular meals, stay up late at night, or suffer from prolonged mental stress?

Are you exposed to radiation, organic solvents and other harmful substances for a long time?

Have you suffered from AIDS, malnutrition, etc.?

Any history of food or drug allergy?

Test results in the last six months, which can be carried to the doctor

Laboratory tests: blood routine, liver and kidney function, electrolytes, tumor markers, blood gas analysis, etc.

Imaging tests: chest X-ray, chest CT, chest MRI, etc.

Pathological examination: biopsy of primary tumor or lung mass.

Others: bronchoscopy, lung function, etc.

Medication used in the last 3 months, if available, bring the box or package to the doctor

Painkillers: e.g. Ibuprofen, Loxoprofen sodium, Celecoxib, etc.

Cough suppressants and expectorants: e.g. Ambroxol, Methocarbamol, Dextromethorphan, etc.

Antibiotics: e.g. amoxicillin, cefadroxil, cefdinir, etc.

Diagnosis

Diagnosis is based on

Medical history

Previous diagnosis or high suspicion of malignant tumor of other organs.

Have long-term smoking, drinking, late night, excessive mental stress and other bad life habits or conditions.

Long-term exposure to radiation, chemical solvents and other toxic and harmful substances.

Suffering from malnutrition, AIDS and other diseases or long-term use of glucocorticoid and immunosuppressant drugs.

Clinical manifestations

No specific symptoms, some patients may have respiratory system related symptoms.

Tumor invasion into the pleura may lead to chest pain.

Cough and sputum may occur when the tumor is secondary to infection or obstructive pneumonia.

When the tumor blocks the bronchial tubes and causes pulmonary atelectasis, the patient may have symptoms of stridor.

Patients may suffer from hemoptysis of different degrees when the tumor is hemorrhagic and necrotic.

When the tumor causes pleural effusion, patients may have panic attacks.

Lack of specific signs, physical examination is not the main means to diagnose this disease.

Dry rales can be heard on auscultation of the lungs when bronchial stenosis is caused by blockage of airways by tumor tissue.

When lung inflammation is caused by secondary infection of tumor tissue, wet rales and blister sounds can be heard on auscultation.

When the patient develops pulmonary atelectasis or pleural effusion, decreased lung breath sounds may be heard on chest auscultation.

Laboratory tests

Laboratory tests may be performed to determine whether the patient has secondary anemia or infection of the lung tissue.

Red blood cell counts and hemoglobin levels may be lowered if the patient is anemic due to recurrent hemoptysis or nutrient depletion.

Patients with lung infections may have elevated levels of white blood cells and neutrophils.

Determine whether the patient has complications such as hypoproteinemia.

If the patient is hypoproteinemic due to high nutrient depletion, the test results may show low total protein and albumin.

Determine whether the patient has secondary electrolyte disorders.

If the patient has electrolyte disorders due to malignant disease, the test results may show abnormally high or low levels of electrolytes such as sodium, potassium, and chloride.

Clarify whether there is an acid-base balance disorder in the patient’s body.

If the tumor tissue seriously affects the ventilation function of the lungs, causing the patient to develop respiratory acidosis, the patient may have arterial blood PH, PO2 lowering, PCO2 elevation and so on.

Preliminary clarification of the type of the patient’s primary tumor can be made, while efficacy monitoring and prognosis assessment can be carried out.

If the lung metastatic tumor is caused by squamous epithelial cell carcinoma such as esophageal cancer, cervical cancer, etc., the tumor marker assay may suggest that squamous epithelial cell carcinoma antigen is elevated.

If the lung metastatic tumor is caused by adenoepithelial cell carcinoma such as gastric cancer and colon cancer, the tumor marker test may suggest that carcinoembryonic antigen is elevated.

Patients with hepatocellular carcinoma may have elevated alpha-fetoprotein, and patients with breast cancer may have elevated Glycosylated Chain Antigen 153.

Imaging examination

It is the most important examination tool for lung metastatic tumor and has important reference value for the formulation of treatment plan.

Patients with more obvious lung metastatic tumors may show one or more irregularly shaped round-like masses in the lung field area on lung X-ray.

Due to the low density resolution of chest X-ray and the possibility of being obscured by structures such as the sternum, it is difficult to detect smaller metastatic foci, so it is not the preferred examination modality and is only used in areas with less favorable medical conditions.

Density resolution is better, which can clearly show the size, location and number of metastatic foci, and help to initially determine the extent of invasion of lung metastatic tumors.

It can clearly display the bony structures such as sternum and ribs, and clarify the degree of invasion of the tumor on the sternum and other structures.

With good tissue resolution, the degree of invasion of lung metastatic tumor on pericardium, mediastinum, large blood vessels, lymph nodes and other soft tissue structures can be observed more clearly.

Fiberoptic bronchoscope

It can visually observe the internal condition of the patient’s airway, which helps to clarify the invasion of the airway by the tumor.

It can to a certain extent understand whether the tumor shows secondary changes such as necrosis and infection, and at the same time understand the compression or blockage of the airway by the tumor tissue.

If necessary, appropriate tumor biopsy can be taken for pathological examination.

Lung function test

The degree of airway blockage caused by the tumor can be indirectly assessed by checking the ventilation function of the patient’s lung tissue, and then initially clarify the impact of pulmonary metastatic tumor on respiratory function.

If the tumor causes extensive airway obstruction, the patient may show different degrees of ventilation dysfunction.

Pathologic examination

It is an important criterion for the diagnosis of this disease.

If the primary tumor has been clearly diagnosed by pathological biopsy, pathological biopsy of lung metastases is not one of the necessary examinations for the diagnosis of this disease.

If the primary tumor is unknown or the pathological tissue is difficult to obtain, the disease can be clearly diagnosed by pathological examination of lung metastases.

Pathologic tissue can be obtained by tracheoscopy and CT-guided percutaneous lung puncture.

Diagnostic criteria

If the patient has been diagnosed with malignant tumors in other tissues or organs, and at the same time, single or multiple round-like soft tissue masses with clear or unclear borders are found in the lungs by lung imaging, the disease can be diagnosed initially, and it is not necessarily necessary to carry out pathological examination.

If the patient presents with a suspected lesion in the lung, but the primary tumor is unknown or the pathological tissue is difficult to obtain, or if it is difficult to determine the nature of the lesion in the lung by imaging, pathological biopsy is required, and the diagnosis can be clarified when the presence of malignant tumors originating from other types of tissues is found in the lung lesion.

Differential diagnosis

Lung cancer

Similarities: patients may have chest pain, cough, sputum, hemoptysis and other symptoms.

Differences:

Lung cancer patients’ first lesion is in the lung, and most of them are not accompanied by primary malignant tumors of other organs; patients with lung metastatic tumors usually have been clearly diagnosed with primary malignant tumors of other organs.

Imaging examination of lung cancer patients often indicates the presence of soft tissue mass in the lungs with irregular boundaries and unclear demarcation from the surrounding tissues; the edges of the lesions of lung metastatic tumors are mostly more regular.

Lung puncture biopsy can clarify the diagnosis.

Tuberculosis

Similarities: patients may have cough, hemoptysis and other symptoms; lung imaging may show mass-like shadow in the lungs.

Differences:

Patients with tuberculosis are often accompanied by symptoms such as low-grade fever and night sweats; patients with metastatic tumors in the lungs may not have these symptoms.

T-spot test, tuberculin test and pathologic biopsy can be used for differentiation.

Pneumonic pseudotumor

Similarity: Both may appear as round-like soft tissue masses in the lungs on lung imaging.

Differences:

Patients with pneumonic pseudotumor have a history of recurrent bacterial or viral infections in the lungs; patients with pulmonary metastatic tumors usually have primary malignancies in other organs.

Pneumatoid pseudotumors are usually solitary and progress slowly; metastatic lung tumors can be multiple and usually progress at a faster rate.

Pathologic biopsy can clearly differentiate them.

Treatment

Aims of treatment: It varies according to the patient’s physical condition and the degree of progression of the disease.

For patients with good physical condition, limited primary tumor and solitary lung metastatic lesion, generally aim to achieve cure.

For patients whose primary tumors have spread to a certain extent, or there are multiple metastatic foci in the lungs, which are difficult to be cured radically, we generally strive to achieve the purpose of delaying the progression of the disease and prolonging the survival period.

For patients whose condition has entered the advanced stage with obvious clinical symptoms, the treatment aims to alleviate patients’ pain and improve the quality of survival.

Treatment principle:

For patients with more limited primary tumors, solitary lung metastases and those who can tolerate surgery, surgery is generally preferred, with postoperative adjuvant radiotherapy.

For people whose primary tumor has spread significantly, there are multiple metastases in the lungs, and it is difficult to achieve the radical effect of surgery, radiotherapy, chemotherapy, targeted therapy, immunotherapy and other comprehensive treatment modalities are generally preferred.

For patients with advanced disease and obvious clinical symptoms such as pain and wheezing, palliative treatment is generally preferred.

General treatment

It refers to conditioning through diet and lifestyle to improve the patient’s physical quality and increase his/her adherence to treatment.

Reasonable diet

Eat more protein-rich foods and more fresh fruits and vegetables to supplement vitamins and minerals.

Eat less greasy, barbecue and spicy food to avoid gastrointestinal discomfort and aggravate the discomfort caused by the treatment.

Quit smoking and drinking

Tobacco and alcohol are very harmful to the body and may accelerate the progress of the tumor.

Moderate exercise

Moderate exercise can improve the body’s resistance and help the body to kill tumor tissues by itself. At the same time, it can also reduce the uncomfortable symptoms brought by radiotherapy.

Surgery

Surgery is suitable for patients with metastatic lung tumors who meet the following conditions.

The primary tumor can be effectively controlled.

After complete removal of the metastatic lesions, the remaining lung tissue can maintain the patient’s normal respiratory function.

There is no extra-thoracic metastatic lesion.

The patient is in good physical condition and can tolerate surgical treatment.

The preferred surgical procedure is pulmonary wedge resection, and lobectomy is also feasible when the tumor size is large.

Surgical methods include open thoracotomy and thoracoscopic surgery, of which thoracoscopic surgery is often preferred because of its advantages of less bleeding, less pain and quicker postoperative recovery.

Radiation therapy

Radiotherapy is suitable for metastatic lung tumors that cannot be completely resected, and postoperative adjuvant treatment for patients with metastatic lung tumors.

It includes radical radiotherapy and palliative radiotherapy.

It is relatively effective for squamous epithelial cancer, such as esophageal cancer, cervical cancer, nasopharyngeal cancer and other lung metastatic tumors.

The purpose of radical radiotherapy is to kill tumor cells as much as possible, so that patients can achieve clinical cure, or patients who cannot be operated can get the chance of surgery.

The purpose of palliative radiotherapy is to reduce the size of the patient’s tumor to a certain extent, so as to alleviate the patient’s pain, wheezing and other symptoms.

Common side effects include radiation pneumonitis, radiation dermatitis, radiation esophagitis, and radiation pleurisy.

Internal medicine treatment

The internal medicine treatment of lung metastatic tumor mainly refers to the application of chemical, targeted and immunotherapy drugs. The drugs used have strict indications, and there may also be contraindications and adverse reactions, so please be sure to follow the doctor’s instructions for the use of drugs.

Chemotherapy

It is applicable to most of the lung metastatic tumors that cannot be surgically resected, and postoperative adjuvant therapy for patients with lung metastatic tumors.

Depending on the type of primary tumor, the selected chemotherapy regimen varies.

Common side effects of chemotherapy include gastrointestinal discomfort, bone marrow suppression, rash, hair loss, abnormal blood clotting function, allergy to chemotherapeutic drugs and so on.

Targeted therapy

It is applicable to lung metastatic tumors caused by some primary tumors with corresponding specific targeted drugs.

For example, some patients with metastatic lung tumors caused by hepatocellular carcinoma can try to apply sorafenib, and some patients with metastatic lung tumors caused by HER-2 positive breast cancer can try to apply trastuzumab.

Some patients can effectively control the disease, and some patients may be ineffective.

Immunotherapy

It is suitable for primary tumors with immunotherapy indications.

Commonly used drugs are PD-1/PDL-1 antibodies.

Common side effects include immune-related pneumonia, hepatitis, myocarditis, thyroiditis, colitis, conjunctivitis and nephritis.

Interventional therapy

For patients with a small number of lung metastases and no metastases to other sites but who have difficulty tolerating surgery.

It includes percutaneous radiofrequency ablation therapy and anhydrous ethanol injection therapy.

It is easy to be accepted by patients as it is less damaging to patients and has more accurate therapeutic effect.

Prognosis

Cure

Patients who cannot be completely resected by surgery will have a continuous progression of the disease, which will eventually lead to death.

Patients with fewer lung metastases and more limited primary tumors can achieve long-term survival after surgery.

Some patients, even after resection of lung metastases, may still die after surgery due to recurrence of the primary tumor.

The prognosis of patients is affected by a variety of complex factors, such as the type of primary tumor, their health status, and the degree of progression of the disease, and there is no definite data on the overall cure rate and survival time.

Prognostic factors

Patients with extensive invasion of surrounding tissues by the primary tumor or multiple metastases have a higher recurrence rate after treatment and a relatively poorer prognosis.

Patients with multiple lung metastases or more serious invasion of important tissues such as mediastinum and large blood vessels by metastatic lesions often cannot be completely resected, and the prognosis is generally poor.

The degree of malignancy of the primary tumor is higher, such as the recurrence rate of patients with lung metastatic tumor whose primary tumor is pancreatic cancer or gastric ring cell carcinoma is higher, the disease progresses at a faster rate, and the prognosis is poorer.

Hazardousness

Lung metastatic tumor is a very harmful disease, and its harmfulness is similar to most other malignant tumors.

Depletion of nutrients in the body, leading to malignant disease in patients

Lung metastatic tumor usually grows faster and consumes a lot of amino acids, glucose and other nutrients in the body, resulting in anemia, hypoproteinemia, and even malignant disease, which leads to the death of patients.

Metastasis to other parts of the body, destroying other organs

The metastatic foci may continue to metastasize to other organs in the body, such as pleura, pericardium, etc., resulting in functional failure of the corresponding organs and even endangering life.

Complicated infection

The metastatic lesion itself may develop secondary changes such as necrosis and infection, causing the patient to develop fever and even complications such as pyothorax and mediastinal infection.

Causing pain

If the metastatic lesion invades the sternum, nerves and other structures, it may cause persistent pain, which not only affects the patient’s life, but also leads to depression and anxiety.

Daily

Daily management

Dietary management

Eat a light diet with plenty of protein-rich foods, including tofu, fish, shrimp, and lean meat.

Eat more fresh fruits and vegetables to maintain balanced nutrition.

Quit smoking and drinking.

Moderate Exercise

Aerobic exercise is the mainstay, including jogging and swimming.

The aim is to improve resistance and reduce treatment-related side effects.

Psychological support

Actively learn about tumor-related diseases, common treatment methods and precautions in life.

Patients should maintain a positive and optimistic mindset, and seek psychological counseling when necessary to enhance confidence in treatment, which will help ensure treatment compliance.

Follow-up and review

It varies from person to person, depending on the treatment method and the degree of progression of the disease. Please follow the doctor’s instructions. The general principles are as follows:

Surgical patients

Chest CT examination is performed 3 months after surgery for evaluation.

Depending on the patient’s tumor type, follow-up review is performed every 3-6 months after surgery, and the items include chest CT and tumor markers.

Follow-up examinations should be performed for at least 5 consecutive years.

Non-surgical patients

Follow-up every 3 months, including chest and abdominal CT, whole-body bone scan, tumor markers, etc. Fully understand the progress of the disease.

Prevention

As tumor metastasis is a particularly complex process with complicated mechanisms, there is no specific means of prevention at present. Common prevention methods are as follows.

Actively treat primary malignant tumors in other tissues and organs. Follow up and review regularly according to medical advice.

Avoid smoking and drinking in normal life, and maintain balanced nutrition.

Moderate physical exercise and keep a good mood.

Avoid exposure to radiation and toxic chemicals.

Regular physical examination is recommended for people over 40 years of age for targeted examination of common tumors, commonly used items include low-dose CT of the chest, gastrointestinal endoscopy, and tumor markers.