Lung Cancer
肺癌成因及症狀檢查，有效防護和診療，提高肺癌存活率
肺癌 (Lung cancer) 是本港癌症的頭號殺手，而大多數肺癌患者都是吸煙人士。早期肺癌並沒有明顯的症狀，通常是其它檢查照射胸部X光時才被發現。如能及早診斷出肺癌，在肺癌初期就接受診療的患者在未來五年存活率也有五成之多。防護肺癌避免吸煙或吸入二手煙也至關重要的。
Lung cancer ranks first among fatal tumors in Hong Kong, with both men and women having the highest mortality rates from malignant tumors. Data indicates that men are more likely to develop lung cancer than women. Lung cancer typically arises from changes in the epithelial cells of the bronchi and bronchioles, leading to uncontrolled growth of lung tissue cells. If not detected early, the malignant tumor may spread to nearby tissues or other parts of the body. However, early detection and treatment can significantly improve the five-year survival rate for patients treated in the initial stages. Therefore, in addition to avoiding smoking or secondhand smoke, regular health check-ups are critical.
As the leading cause of cancer-related deaths, the survival rate for lung cancer is closely related to the timing of diagnosis and treatment. Studies show that if lung cancer is detected in the first stage and treatment is initiated immediately, the five-year survival rate can be as high as 50%. In contrast, if the cancer is discovered in the third stage, the five-year survival rate drops to around 15%.
Symptoms of Lung Cancer
Lung cancer has no obvious symptoms in the early stage and is usually detected only during other X-ray examinations for the chest. As the condition worsens, lung cancer patients may experience the following symptoms:
- Shortness of breath
- Persistent cough
- Blood in the sputum
- Hoarseness: may be caused by cancer cells pressing the recurrent laryngeal nerve
- Difficulty in Swallowing
- Pain when taking deep breaths
- Repeated or chronic infection in the chest and lungs
- Loss of appetite
- Weight Loss
- Fatigue
In addition to the above symptoms, there are some less commonly noticed indicators, including:
- Increased thirst and frequent urination
- Clubbing of fingers or toes (enlargement and thickening of the fingertips or toes)
- Numbness or tingling in the shoulders or upper arms
- Unexplained hoarseness
- Swelling and discoloration of the upper body
- Horner's syndrome (drooping of the eyelids, smaller pupil size, reduced sweating on the affected side of the face)
If lung cancer has developed into an advanced stage, the cancer cells may spread. The patient may also experience symptoms such as swollen lymph nodes in the neck, abdominal distension, bone pain, headache, or swelling of the neck, face, and hands, or even partial epilepsy or hemiplegia. Therefore, if you experience the above symptoms, seek medical advice as soon as possible for a lung cancer diagnosis.
Causes of Lung Cancer
- Smoking
- Smoking is the main cause of lung cancer. The risk of lung cancer among smokers is 20 times higher than that of non-smokers, and up to 90% of male lung cancer patients are smokers.
- Second-hand smoke
- Second-hand smoke is also one of the causes of lung cancer. The risk of having lung cancer for people who constantly inhale second-hand smoke is two times higher than that of general people.
- Inhalation of chemical substances
- The long-term exposure to certain chemicals or construction materials, such as asbestos, nickel, uranium, etc.
- Long-term inhalation of cooking fumes
- Long-term inhalation of smoke from burning incense sticks
- Unhealthy diet
- The frequent consumption of grilled or marinated foods, and the inadequate consumption of vitamin A-rich foods, fresh vegetables and fruits.
- Hereditary factors
- Patients with parents or siblings diagnosed with lung cancer will have a higher risk of developing lung cancer than others.
Survival Rate of Lung Cancer
Screening and Diagnosis of Lung Cancer
Medical consultation:
Medical History (e.g. gynaecological disease, obstetric history), allergies, family medical history, plans for pregnancy and contraception methods, menstrual cycle, etc.
Physical examination:
Measure height, weight, blood pressure, check for anaemia and thyroid disease.
Chest X-ray:
The examination is the most basic method for detecting lung cancer and assessing the condition of the lungs. If any abnormalities are detected on the X-ray, further testing can be arranged. However, lesions smaller than 1 cm can be difficult to detect and interpret.
CT scan:
It is one of the most effective ways to detect lung cancer, providing more detailed images than a chest X-ray. It can detect tumors smaller than 0.3 cm and help doctors determine the stage of cancer.
MRI:
Similar to CT scanning, it provides detailed soft tissue images, but it uses radio waves and strong magnetic fields instead of X-rays. It is often used to check whether cancer cells have spread to the brain or spinal cord.
The earlier detection of lung cancer brings a higher chance of recovery. Therefore, smokers or frequent passive smokers should have regular check-ups and stay vigilant. If you suspect any symptoms of lung cancer, you should seek medical advice and examination.
- Chest X-ray: Observe any tumours or other abnormal substances in the lungs
- Sputum cytology: Use a microscope to observe the presence of cancer cells in the sputum
- Bronchoscopy: Examine the mucous membrane in the bronchi, and extract tissues for pathological examination to examine the type of cancer cells
Diagnosis of Lung Cancer
After the initial examination, the doctor may request further cancer tests such as mediastinoscopy, computerised tomography (CT scan) and endoscopic ultrasound (EUS). These tests facilitate the precise classification of the types and stages of the patient’s lung cancer.
- Mediastinoscopy
The patient is put under general anaesthesia to make two to three small incisions at the bottom of the neck and on the top of the breastbone. An endoscope is inserted to observe the lymph nodes and thymus glands surrounding the lungs and heart.
- Computed Tomography (CT Scan)
The patient will be injected with a contrast agent before the scan. Then a CT scan will be used to take X-ray images of body tissues from different angles to form a 3D picture.
- Endoscopic Ultrasound (EUS)
A soft tube with an ultrasound transducer is inserted into the patient's oesophagus through the mouth. The rebounding sound waves from the heart and lungs will be visualized by the computer to observe if the lymph nodes in the chest cavity are swollen.
There are three types of lung cancer:
- Small cell lung cancer
- This type of cancer develops from the smallest cell of the lung, usually the one in the bronchial wall. Cancer worsens with the rapid spread of cancer cells to other parts of the body in the early stage, making it difficult to cure.
- Non-small cell lung cancer
- Squamous cell carcinoma: It is commonly found in the tracheal wall and is usually caused by smoking
- Adenocarcinoma: It is caused by the abnormal growth of the mucus-secreting cells in the trachea wall and affects mainly the outer lung.
- Large cell carcinoma: involves larger and rounder cancer cells.
- Carcinoid (neuroendocrine tumour)
Lung cancer diagnosis and treatment
診療肺癌有五種主要方法，包括化學診療、放射診療、標靶診療及免疫診療 ，亦可視乎患者的情況，單獨或合併其他紓緩症狀的方法一起使用。
- Chemotherapy
Chemotherapy, also known as “Chemo”, uses an intravenous injection to inject cytotoxic drugs through the bloodstream to kill the cancer cells by blocking their growth and division.
- Radiology
Also known as "radiotherapy," this method uses high-energy rays to target and kill cancer cells. It can be used as a curative treatment for early-stage lung cancer and is also applicable when tumors have locally spread or as a means to eliminate residual cancer cells after treatment. Radiation therapy is suitable for patients who are elderly or have other health issues that make them unsuitable for surgery.
- Targeted Therapy
Targeted therapy is designed to target specific characteristics of cancer cells and generally has fewer side effects than conventional chemotherapy. It is suitable for patients with advanced lung cancer. Lung cancer targeted therapy is considered one of the most developed forms of treatment among all tumors, with about ten gene mutations that correspond to specific targeted drugs. Using targeted medications for precise treatment results in a high response rate for tumor reduction, with fewer side effects compared to chemotherapy.
- Immunotherapy
針對中晚期非小細胞肺癌患者而設，部分免疫訊號較強(PD-L1)的晚期患者甚至可只用免疫診療而無需接受化療。部分非轉移性的第三期患者，在同步做化療電療後可進行免疫診療作鞏固診療，有助降低復發風險。
Recovery and Rehabilitation of Lung Cancer
Lung cancer has a high recurrence rate, so patients need to have regular check-ups during their recovery period so that they can receive timely treatment if a recurrence occurs.
In addition, patients have to pay attention to their daily diet and adopt a balanced diet. If patients have any other chronic diseases or dietary concerns, seek medical advice from doctors. Adequate hydration can reduce mucus viscosity and facilitate coughing up the sputum.
Patients should also maintain a regular lifestyle and a pleasant mind. Proper rest and adequate sleep can help relieve stress and promote recovery after the surgery. Keep the house well-ventilated and avoid going to crowded places with turbid air to help prevent respiratory infections. Adequate exercise can also enhance lung function and foster recovery.
Most importantly, patients must quit smoking and avoid inhaling second-hand smoke to better let their lungs recuperate.
肺癌防護
要防護肺癌，要有所行動，除了避免染上不良嗜好外，建議應該定期做身體檢檢查，保障自己身體健康。
Non-smokers should stay away from bad habits, while smokers should quit smoking as soon as possible. You should avoid second-hand smoke and go to places where many people smoke. Avoid going to popular smoking areas with a high chance of inhaling second-hand smoke.
As for hazardous substances, you should be alert and test your residence for the presence of hazardous substances such as asbestos. Employees should also follow safety guidelines and wear protective masks in their workplaces.
另外，從飲食習慣著手，多吃蔬果，保持健康身體。定期進行健康檢查，防患未然，及早發現疾病及了解身體功能異常狀況，作出跟進，從而發揮防護作用。
Lung Cancer FAQ
Q: Is lung cancer hereditary?
The genetic mutations associated with lung cancer are usually acquired during a person's lifetime and are not hereditary. Acquired mutations in lung cells are usually caused by exposure to factors in the environment, such as carcinogenic chemicals in tobacco smoke.
Q. Is it possible to have lung cancer without the symptoms of coughing?
Shortness of breath and wheezing may also be the early signs of lung cancer. In addition to shortness of breath, some people may have a mild cough. Others may have difficulty in breathing but no cough.
Q: What age group is the most affected by lung cancer?
Lung cancer mainly occurs in older people. Most people diagnosed with lung cancer are 65 years old or above; only an extremely small number of diagnosed patients are below 45 years old. The average age of diagnosed patients is about 70 years old.
