a pulmonary malignancy attributable to cigarette smoking in 50% of cases. Other predisposing factors are exposure to acronitrile, arsenic, asbestos, beryllium, chloromethyl ether, chromium, coal products, ionizing radiation, iron oxide, mustard gas, nickel, petroleum, uranium, and vinyl chloride. Lung cancer develops most often in scarred or chronically diseased lungs, and is usually far advanced when detected, because metastases may precede the detection of the primary lesion in the lung. Symptoms of lung cancer include persistent cough, dyspnea, purulent or blood-streaked sputum, chest pain, and repeated attacks of bronchitis or pneumonia. Diagnostic measures include x-ray films, fluoroscopy, tomography, bronchography, angiography, cytologic studies of sputum, bronchial washings or brushings, and needle biopsy. Epidermoid cancers and adenocarcinomas each account for approximately 30% of lung tumors, about 25% are small or oat cell carcinomas, and 15% are large-cell anaplastic cancers. Epidermoid tumors tend to remain in the thorax, but other lung lesions metastasize widely; small cell carcinomas frequently invade bone marrow and the central nervous system, and large-cell cancers frequently metastasize to mediastinal nodes and gastrointestinal mucosa. Surgery is the most effective treatment, but only one half of the cases are operable at the time of diagnosis and of these 50% are not resectable. Thoracotomy is contraindicated if metastases are found in contralateral or scalene lymph nodes. Irradiation is used to treat localized lesions and unresectable intrathoracic tumors and as palliative therapy for metastatic lesions. Radiotherapy may also be administered postoperatively to destroy remaining tumor cells and may be combined with chemotherapy. Remissions are obtained in some cases treated with chemotherapeutic agents, such as cyclophosphamide, procarbazine, cisplatinum, VP-16, doxorubicin hydrochloride, and bleomycin. Chemotherapy is especially indicated for small cell carcinoma. Postoperatively, bacillus Calmette-Guérin vaccine, an antituberculosis drug that stimulates the immune system, is administered to some patients with early stage lung cancer.

DR SOON is a medical practitioner. He holds four degrees. MBBS (University of Malaya), MBA (University of East Asia), LLB (Hons) (University of Wolverhampton), Master of Medicine (Edith Cowan University)