Because the clinical symptoms and signs of lung cancer appear late and the manifestations are complex and diverse, more than 50% of the cases diagnosed clinically are at advanced stages. This leads to difficulties in lung cancer treatment and low survival rate of patients. Some lung cancer patients have very special early manifestations, some even have no symptoms, and the tumor is only discovered during physical examination, which can easily lead to misdiagnosis and mistreatment and delay the best time for treatment. Therefore, it is beneficial to understand the common manifestations of lung cancer and to screen the high-risk group of lung cancer, which is conducive to early detection, early diagnosis and early treatment of lung cancer.
Early Screening of Lung Cancer
What are the early screening methods for lung cancer?
Early screening methods for lung cancer include sputum exfoliation cytology, chest X-ray (chest radiograph), low-dose spiral CT and bronchoscopy. The combined application of these methods can improve the detection rate of lung cancer, and the results of these examinations should be considered together when making diagnosis.
1.Sputum exfoliative cytology examination
This test is simple and convenient, and it is a non-invasive diagnostic method. The specific method is to keep the sputum after canceling the morning deep cough for three consecutive days and to conduct sputum exfoliative cytology smear examination to obtain the diagnosis.
2.Chest X-ray
Chest X-ray is an important basic means for early detection of lung cancer, and it is economical. Early stage lung cancer usually appears as small masses in chest X-ray, which is not easily distinguished from inflammation at this time. This should be judged on a case-by-case basis and reviewed after anti-inflammatory treatment. If the lump does not become smaller but bigger, the possibility of lung cancer should be highly suspected. In addition, some characteristic X-ray signs can be found on the chest X-ray, such as lobar sign, burr sign and vascular cluster sign, which are also manifestations of malignant tumor.
3.Low-dose spiral CT
Low-dose spiral CT is the most effective and safe means of early lung cancer screening, which can detect microscopic lung cancer with a diameter of <1 cm, and its detection rate of early lung cancer is as high as 80%. 80%-90% of patients with early lung cancer detected by CT can be cured by minimally invasive surgery without further radiotherapy. The radiation dose of conventional CT examination is 60 to 100 times that of chest X-ray, so it is not suitable as a routine screening method for lung cancer. However, the radiation level of low-dose spiral CT is only about 1/4 of that of conventional CT, and the US National Lung Cancer Screening Trial (NLST) has confirmed that annual low-dose spiral CT screening does not pose any health risk to the screeners.
4.Bronchoscopy
This is the most common method to diagnose lung cancer, including bronchoscopic brushings, biopsies and bronchial lavage under direct vision, which can obtain pathological diagnosis.
For those who are found to have suspicious small nodules in the lung by screening, an objective risk assessment should be performed in the context of their specific conditions before further management. In general, CT should be reviewed every 6 months for lung nodules <5 mm, every 3 months for lung nodules 5 to l0 mm, and every 1 to 2 months for lung nodules >10 mm.
Who should be targeted for early screening of lung cancer?
High-risk group of lung cancer refers to those who have higher risk of lung cancer and are more likely to develop lung cancer. Early screening for lung cancer should focus on this high-risk group.
(1) Long-term active smokers over 40 years old with smoking index (number of cigarettes smoked per day × number of years of smoking) > 400.
(2) Long-term passive smokers.
(3) Long-term sufferers of external environmental pollution and indoor small environmental pollution (such as soot, cooking fumes, radioactive substances in decorative materials, etc.).
(4) Occupational exposure to carcinogens. Occupational carcinogens of lung cancer include asbestos, radon, nickel, chromium, arsenicals, dichloromethyl ether, chromium compounds, nickel compounds, soot, tar and polycyclic aromatic hydrocarbons in petroleum, etc.
(5) Patients with chronic lung diseases.
(6) People with family members who have suffered from lung cancer.
What are the common manifestations of lung cancer? What does each represent?
The symptoms of lung cancer may appear suddenly or gradually. Only with a comprehensive understanding of the symptoms and signs of lung cancer can the diagnosis and treatment be confirmed as early as possible.
(1) Lung manifestations of lung cancer
The typical lung symptoms of lung cancer are irritating cough, blood in sputum, chest pain, fever and shortness of breath.
Irritating cough is the most common symptom of lung cancer, and blood in sputum is the most meaningful symptom to diagnose lung cancer. If the cough is new and has not improved after more than two weeks of treatment, or if there is a past history of long-term chronic cough and the nature of the cough has recently changed (e.g. cough with sputum becomes dry cough without sputum, change in cough tone or sputum with blood), one should be highly alert to the possibility of lung cancer.
Blood in sputum means sputum with blood or blood clots, often persistent or intermittent, repeatedly and in small amounts, which is a more characteristic manifestation of lung cancer. However, in early stage of lung cancer, blood in sputum is usually not a big hemoptysis, because blood in sputum is a manifestation of invasion of capillaries adjacent to the tumor, and capillaries have quite strong self-healing ability, so minor breakage will heal itself quickly, so after appearing once, blood in sputum will not appear again for a long time. This phenomenon often paralyzes many patients, making them lucky and not eager to seek medical help, thus delaying the condition. Therefore, even a single hemoptysis should be highly valued.
The chest pain in the early stage of lung cancer often appears as intermittent hidden pain or heavy feeling, or persistent dull pain, often accompanied by chest tightness, and the location of chest pain is not fixed.
(2) Performance of lung cancer paraneoplastic syndrome
Paraneoplastic syndrome of lung cancer refers to a series of clinical manifestations caused by some special hormones, antigens, enzymes or metabolites produced by cancer cells, which are not related to direct erosion, metastasis, obstruction or compression of lung cancer, and these symptoms and signs can be manifested in various organs other than lung. The significance of understanding the paraneoplastic syndrome is that these signs and symptoms often precede tumor exposure and can be clues to early diagnosis; some signs or symptoms (such as hypercalcemia) are far more dangerous than lung cancer itself and require immediate and specific treatment. Effective treatment of swelling and pain can make this syndrome disappear. Some common lung cancer paraneoplastic syndromes are listed below. Once patients find similar symptoms or signs, they need to pay attention to the screening of malignant tumors when seeking medical treatment.
1. Cachexia (also called cachexia syndrome with loss of appetite)
The clinical manifestation of this syndrome is that the tumor patient is emaciated and exhausted. On the one hand, due to excessive and rapid growth of tumor, it consumes a lot of heat and protein, and when combined with bleeding, fever and infection, this consumption will increase exponentially. On the other hand, patients with tumor ringworm have decreased appetite due to pain and fever, and some of them may have difficulty swallowing and vomiting, or even cannot eat at all, causing the body to fail to take in enough calories and nutrients. Its best treatment is to cure the primary tumor so as to completely improve the metabolic disorder, and also to improve appetite and increase body weight with medications (such as megestrol). In addition, necessary enteral and parenteral nutritional support treatment can be given.
2. Bone, muscle and skin manifestations
① Pestle-like finger (toe), which is manifested by the obvious widening and thickening of the terminal finger (toe) joint and arch-shaped elevation of the finger (toe) nail from the root to the end, is often the only symptom of early stage of lung cancer. ②Pulmonary hypertrophic osteoarthropathy, which manifests as symmetrical joint swelling and pain, with large joint involvement being the most common, is often misdiagnosed as rheumatoid arthropathy. ③Some special skin and muscle lesions, such as polymyositis, dermatomyositis, scleroderma, etc.
3.Hematological system syndrome
①Anemia, purpura (petechiae of skin and mucous membrane), erythrocytosis, leukemia-like reaction, etc. Deep vein thrombosis, which mostly occurs in the lower limbs, manifests clinically as swelling of the limb on the side of the thrombus, and once the thrombus is dislodged, it can cause symptoms related to pulmonary embolism, which can be life-threatening in serious cases. Lung cancer patients are at high risk of deep vein thrombosis because of their hypercoagulable blood and long-term bed rest. Anticoagulation therapy is the standard treatment for venous thrombosis, which can effectively inhibit the spread of thrombus and reduce the chance of pulmonary embolism.
4.Ectopic endocrine syndrome
(1) Gynecomastia is caused by the secretion of gonadotropins from lung cancer cells, and is often associated with pulmonary hypertrophic osteoarthropathy, and individual patients also have testicular atrophy. This symptom can easily be misdiagnosed as ordinary breast enlargement. ②”Full-moon face”, “buffalo back” and purple skin stripes are manifestations of Cushing’s syndrome, which can be caused by the secretion of pro-adrenocorticotropic hormone-like substances by lung cancer cells causing fat deposition. Such symptoms are often misdiagnosed as endocrine system diseases. (3) Gastrointestinal symptoms such as poor appetite, nausea, vomiting, weakness or drowsiness can be caused by the secretion of anti-diuretic hormone by lung cancer cells. These symptoms are often misdiagnosed as digestive system diseases. ④ Nausea, vomiting, drowsiness, irritability, polyuria and mental disturbance are caused by secretion of parathyroid hormone from lung cancer, mostly seen in squamous lung cancer. ⑤ Asthma-like dyspnea, paroxysmal tachycardia, watery diarrhea and skin flushing, itching and herpes zoster are manifestations of lung cancer syndrome, which are caused by excessive secretion of 5-hydroxytryptamine (a substance regulating neural activity) by lung adenocarcinoma cells or small cell lung cancer cells.
5.Hypercalcemia
Clinical manifestations may include anorexia, nausea, vomiting, constipation, polyuria, polyhydramnios, etc. In severe cases, mental confusion, drowsiness, blurred consciousness and coma may occur. This is a kind of tumor emergency, which can endanger patients’ lives if not treated in time.
6.Neuromuscular syndrome
It has lower limb edema, muscle atrophy, muscle weakness, uncoordinated limb movement and abnormal sensation, etc. Its specific cause is still unclear and may be related to autoimmune mechanism.
In addition, there are other manifestations such as paraneoplastic glomerulopathy and hypoglycemia.
7.Presentation of lung cancer invading surrounding tissues
Hoarseness, which often occurs when lung cancer invades the laryngeal nerve and causes vocal cord paralysis.
Facial and neck edema, which occurs when lung cancer invades the superior vena cava, causing obstruction of blood return.
Shortness of breath often occurs when lung cancer invades the pleura and causes pleural effusion, which restricts lung activity.
Continuous severe chest pain, which occurs when lung cancer invades the pleura and chest wall.
Severe chest pain, arm pain, upper limb movement disorder, drooping upper eyelid on the same side, small pupil, sunken eye and no sweat on the face are caused by lung cancer invading ribs and compressing nerves, etc.
8.The manifestation of distant organ metastasis of lung cancer
The most common metastatic sites of lung cancer are brain, bone, liver and adrenal gland.
If headache, nausea, vomiting, dizziness, blurred vision and weakness of one limb appear, brain metastasis of lung cancer should be considered. If there is persistent bone pain with fixed location and elevated plasma alkaline phosphatase (an enzyme with elevated level in skeletal lesions) or blood calcium, bone metastasis of lung cancer should be considered as a possibility. If anorexia, right upper abdominal pain, hepatomegaly, jaundice (yellow skin and sclera) and ascites are present, with abnormal liver function, the possibility of liver metastasis of lung cancer should be considered. Patients with adrenal metastasis may present with manifestations such as hypertension or no symptoms at all. In subcutaneous metastasis of lung cancer, nodules can be palpated under the skin. Lung cancer can also metastasize to body surface lymph nodes, most commonly bilateral supraclavicular lymph nodes. Patients may have localized masses, but they are not painful or itchy and are mostly discovered unintentionally.
When one or more of the above abnormal manifestations occur, the possibility of lung cancer metastasis should be considered, and timely medical consultation should be sought for examination and treatment.