Small Cell Lung Cancer

Introduction to small cell lung cancer Small cell lung cancer (SmallCellLungCancer, SCLC) accounts for about 20% of lung cancer, with high malignancy, short doubling time, early and extensive metastasis, sensitive to chemotherapy and radiotherapy, and high initial remission rate, but it is prone to secondary drug resistance. It is easy to relapse, and the treatment is based on systemic chemotherapy. Disease Classification Histopathology SCLC can be divided into small cell lung cancer (including past oat cell cancer), mixed cancer (ie, a mixture of small cell carcinoma and scale or adenocarcinoma). The most commonly used staging system in the field of SCLC therapy is the SCLC staging system developed by the US Veterans Hospital Lung Cancer Research Group: if the tumor is confined to one side of the chest (including the regional lymph nodes it drains, like the lateral hilar, mediastinum or supraclavicular lymph nodes) and It can be included in a radiotherapy field (LimitedDisease, LD). If the tumor exceeds the limited period, it is an extensive period (ExtensiveDisease, ED), of which the former accounts for about 1/3, and the latter accounts for 2/3. This staging method is simple and easy to perform, and is associated with therapeutic efficacy and prognosis. TNM staging is currently also used for the staging of SCLC. basic knowledge The proportion of illness: 0.015% Susceptible people: more common in middle-aged and elderly Mode of infection: non-infectious Complications: pneumonia, arrhythmia

Causes of small cell lung cancer

Causes:

Smoking is a major risk factor for lung cancer, and SCLC is closely related to smoking. According to a summary analysis of smoking and lung cancer worldwide in 1970-1999, lung cancer was positively correlated with smoking intensity (smoking) and duration, and the relationship with SCLC was most pronounced.

Pathogenesis:

There have been many studies on the molecular mechanisms of SCLC in the past few decades, suggesting that the occurrence of SCLC may involve the participation of multiple genes. Studies have shown that the tumor suppressor gene p53, RB gene (optical neuroblastoma gene), oncogene Bcl-2 gene, Myc gene, PI3K / AKT / mTOR signal transduction pathway are related to the incidence of SCLC.

Pathophysiology

It is generally believed that small cell lung cancer originates from Kulchitsky cells (arginophilic cells) in the bronchial mucosa or glandular epithelium, and belongs to the APUD (amine precursor uptake decarboxylation) tumor. It is also believed to originate from stem cells that can be neuroendocrinely differentiated in the bronchial mucosa epithelium. Small cell lung cancer is the least differentiated type of lung cancer with the highest degree of malignancy. It occurs mostly in the central part of the lung, grows rapidly, and metastasizes earlier. Under light microscopy, the cancer cells are small and short spindle-shaped or lymphocyte-like, with little cytoplasm and resembling naked nuclei. The cancer cells are densely packed in groups, separated by connective tissue, and sometimes the cancer cells are arranged in clusters around small blood vessels. The ultrastructure was observed by electron microscopy. The cytoplasm of the tumor cells contained typical axon-like neuroendocrine granules, but the amount of granules varied, and it was proved to be related to 5-HT and ACTH. From the immunohistochemical study, the tumor cells were positive for Sy for NSE, 5-HT, CgA, and some cases (10%), which proved that small cell carcinoma has neuroendocrine function. In addition, positive immunohistochemical reactions were positive for both CK and EMA in the same tumor.

Small cell lung cancer prevention

Prevention of lung cancer is better than cure, and it is mainly divided into three levels of prevention.

Prevention for healthy people, mainly including non-smoking, away from second-hand smoke pollution. Try to avoid outdoor air pollution and kitchen fumes. Use environmentally friendly decoration materials. Balanced nutrition, eat more grains, vegetables, and fruits. Maintain an optimistic, positive attitude towards life and improve psychological resilience.

Prevention, ie, rehabilitation prevention, patients with lung cancer should follow the doctor's advice and go to the hospital for review.

Small cell lung cancer complications Complications pneumonia arrhythmia

1, respiratory complications: pneumonia, sputum retention, etc. are the most common respiratory complications of small cell lung cancer. This is because when the patient has finished the operation, the coughing phenomenon is often limited by the pain of the wound, so it will easily lead to the occurrence of sputum retention, which leads to lung diseases such as atelectasis.

2, hemothorax, empyema, bronchial pleural fistula: This is a common complication after lung cancer surgery, but the incidence is often relatively low. Once a hemothorax occurs, it must be treated in time because the disease is very harmful. The empyema is often caused by the bronchus and lung secretions contaminating the chest. Bronchial pleural sputum is caused by improper operation of the surgery, retention of bronchial stump cancer, and the like.

3, cardiovascular system complications: blood pressure, arrhythmia.

Small cell lung cancer symptoms common symptoms lymphatic metastasis hemoptysis with chest pain fatigue pulmonary congestion pulmonary infection

Clinical manifestation

Multiple groups: Smoking populations are high-risk populations, and more than 90% of small cell lung cancer patients have a history of smoking. The age of onset is 35-68 years old, and the average age of onset is 60 years. There are more men than women.

Symptoms of the disease: Small cell lung cancer can be asymptomatic in the early stage. The most common symptoms at diagnosis are fatigue (80%), cough (70%), shortness of breath (60%), weight loss (55%), and pain (40-50%). , hemoptysis (25%).

First, the symptoms and signs caused by the primary tumor

(1) Cough: It is a common early symptom, mostly irritating dry cough. When the tumor causes bronchoconstriction, persistent, high-profile metal sound cough can occur. More cough with a small amount of mucus, combined with purulent sputum when secondary infection.

(B) hemoptysis: mostly bloody or intermittent blood stasis in the sputum, a small hemoptysis due to erosion of large blood vessels.

(C) chest tightness, shortness of breath: tumor caused by bronchial stenosis, or tumor metastasis to the hilar or mediastinal lymph nodes, swollen lymph nodes compress the main bronchus or tracheal carina.

Second, the symptoms and signs of tumor expansion in the thoracic cavity

(1) Chest pain: The tumor directly invades the pleura, ribs or chest wall, causing different degrees of chest pain. If the tumor invades the pleura, it will produce irregular dull pain or dull pain. Tumor compression of the intercostal nerve, chest pain can be tired of its distribution area.

(B) superior vena cava syndrome: mostly caused by obstruction of the superior vena cava or less common intracavitary tumor thrombus, manifested as facial, neck, upper extremity edema, jugular vein engorgement, chest congestion and veins The varicose can be accompanied by dizziness, head rise, and headache.

(3) difficulty in swallowing: the tumor invades or oppresses the esophagus, causing difficulty in swallowing.

(d) cough: tracheal esophageal fistula or recurrent laryngeal nerve paralysis caused by drinking water or eating liquid food cough.

(5) hoarseness: occurs when the tumor is directly compressed or metastasized and the lymph node is pressed against the recurrent laryngeal nerve (mostly on the left side).

(6) Horner syndrome: The lung cancer located at the tip of the lung is called the upper sulcus cancer (Pancoast cancer). When the neck 8 and the thoracic sympathetic trunk are compressed, the typical Horner syndrome appears, and the affected eyelids droop and the pupils shrink. The eyeball is invaginated, the ipsilateral face and the chest wall are not sweaty or sweaty; the violation of the brachial plexus is local pain, shoulder joint activity is limited, called Pancoast syndrome.

(7) Pulmonary infection: Recurrent inflammation caused by tumor obstruction of the airway, also known as obstructive pneumonia.

Third, the symptoms and signs caused by tumor extrapulmonary metastasis

(1) Transfer to lymph nodes: The metastasis of the supraclavicular lymph nodes is more fixed, the texture is hard, gradually increasing, increasing, merging, and more painless.

(B) transfer to the pleura: cause chest pain, pleural effusion, pleural effusion is mostly bloody.

(3) Transfer to the bone: more occult, only 1/3 have local symptoms, such as pain, pathological fracture. When transferred to the spinal column to compress the spinal nerve roots, the pain is persistent and exacerbated at night. Intraspinal metastases can rapidly develop irreversible paraplegia syndrome in a short period of time.

(D) transfer to the brain: due to intracranial lesions caused by edema caused by high blood pressure, headache, nausea, vomiting symptoms. It can also cause diplopia, ataxia, cranial nerve palsy, weakness or even hemiplegia on one side due to mass effect.

(5) Transfer to pericardium: There may be pericardial effusion, and even the performance of pericardial tamponade, difficulty in breathing, obvious in supine, jugular vein engorgement, lower blood pressure, narrow pulse pressure difference, systemic congestion, and decreased urine output.

(5) Transfer to the adrenal gland, liver and other parts, causing local organ dysfunction.

Fourth, tumor extrapulmonary manifestations and systemic symptoms

Extrapulmonary manifestations of the tumor include non-specific systemic symptoms such as fatigue, anorexia, and weight loss. Also included are paraneoplastic syndromes, the following are common:

(A) carcinoid syndrome: due to excessive secretion of serotonin caused by asthma-like dyspnea, paroxysmal tachycardia, watery diarrhea, skin flushing.

(B) Eaton-Lambert syndrome: neuromuscular syndrome caused by tumors, including cerebellar cortical degeneration, spinal cord degeneration, peripheral neuropathy, myasthenia gravis and myopathy.

(3) Syndrome of inappropriate antiduretic hormone secretion (SIADHS): manifested as dilute hyponatremia, poor appetite, nausea, vomiting, fatigue, lethargy, and even disorientation.

(D) hypertrophic pulmonary osteoarthrosis: more violation of the upper and lower limbs long bones, clubbing, fingertip pain, hypertrophic osteoarthrosis.

(5) Cushing syndrome: The tumor secretes adrenocorticotropic hormone-like substances and redistributes fat.

Small cell lung cancer examination

Common X-ray examination of the chest is the easiest and cheapest way to check.

Chest computed tomography (CT): can show lesions that cannot be found by ordinary X-ray examination, showing the extent and extent of involvement in the hilar lymph nodes and mediastinum.

Magnetic resonance imaging (MRI): It is not as good as CT in finding small lesions in the lungs, but it can clearly show the relationship between tumors and large blood vessels. Enhanced MRI is preferred when there is no intracranial transfer.

Positron emission computed tomography (PET): Systemic PET is significantly more accurate in determining intrapulmonary masses, lymph nodes, or distant metastases than CT and radionuclide bone scans.

Cytological examination: The positive rate is related to the location and size of the tumor, the quality of the sputum, and whether it is concurrently infected. The detection rate of central lung cancer is high, but it is difficult to identify the type. It is not recommended.

Fiberoptic bronchoscopy: The location and size of the tumor and the extent of infiltration in the bronchial lumen can be observed, and pathological examination of the tissue is performed. Endobronchial Ultrasound (EBUS) is a new technique that can help to define the extent of the lesion and improve the accuracy of transmural biopsy for lesions that have only airway compression without an intraluminal mass.

Percutaneous lung biopsy: completed under CT guidance, the positive rate of biopsy is as high as 90%, and if the tumor contains most necrotic areas, it is often false negative.

Mediastinoscopy: For the diagnosis of mediastinal biopsy, which is difficult to diagnose with conventional methods, the diagnosis of upper mediastinal lymph node metastasis or anterior mediastinal lymph node invasion is significant.

Thoracoscopic and open thoracotomy: Thoracoscopy or thoracotomy biopsy may be considered for difficult-to-diagnose peripheral lesions, mediastinal lesions, or pleural lesions.

Superficial lymph node ultrasound: SCLC is easy to metastasize to the supraclavicular lymph nodes, ultrasonic examination of the neck, supraclavicular, axillary and other places to determine lymph node metastasis.

Abdominal ultrasound, CT or MRI: The liver and adrenal gland are the sites where SCLC is easy to metastasize. The newly diagnosed patients should be examined by abdominal imaging.

Head-enhanced MRI: Enhanced MRI is more sensitive to CT in brain metastases.

Whole body bone scan: The whole body bone scan suggests a site with high metabolism. The medical history should be carefully asked and combined with MRI to determine whether it is metastasis.

Tumor marker examination: The main markers are NSE, CEA, SCC, CYFR21-1, etc., lack of specificity, and have certain reference value for disease monitoring.

Diagnosis and differentiation of small cell lung cancer

diagnosis

Diagnosis can be based on the cause, symptoms and related tests.

Differential diagnosis

It was finally identified by pathology with other types of lung cancer.

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