Carcinoma of the bronchus, [s8]increasingly common

As the result of the greed of multinational companies and the inertia of governments, cigarette smoking is becoming widely prevalent in the developing world. An epidemic of smoking-related diseases has already started, among them carcinoma of the bronchus. About 75% of tumours involve the main bronchi, 10% are peripheral, and a few arise near the apex of the lung, whence they may spread to involve the sympathetic chain and the brachial plexus (Pancoast's tumour). About 50% are squamous cell, 30% are anaplastic (oat cell), and 20% are adenocarcinomas[md]most peripheral tumours are of this kind, and their prognosis after surgery is relatively good.

The patient, who is usually an older man, presents with: (1) A persistent cough. (2) Haemoptysis. (3) A low-grade pneumonia, as the result of a blocked bronchus. (4) Pneumonia which fails to resolve. (5) A solid lesion on X-ray. Bronchoscopy is the critical investigation, and even with a rigid bronchoscope (25.13) it is possible to see and biopsy the lesion in about 75% of cases.

In countries where the disease is common and patients are aware of it, only about 20% of them are operable when they present, and of those who do survive radical surgery, only about 25% are alive 5 years later. The chances of your being able to refer a patient for either radical surgery, or radiotherapy, are small. Radiotherapy is a useful palliative. Present combinations of cytotoxic drugs are of limited value.

You will probably find that most patients are inoperable when they present. So, try to: (1) Differentiate carcinoma of the bronchus from other more treatable diseases, which it may closely resemble, both clinically and radiologically. (2) Select the few ''coin-like' peripheral lesions amenable to surgery. (3) Palliate and comfort the dying and their families.

CARCINOMA OF THE BRONCHUS SPECIAL TESTS. If tuberculosis is a possible differential diagnosis, examine the patient's sputum for AAFB. X- ray his chest.

THE DIFFERENTIAL DIAGNOSIS includes pulmonary tuberculosis, low-grade or partly resolved pneumonia (which may simulate carcinoma closely), areas of pulmonary fibrosis, lung abscesses, and solid tumours of the lung, other than bronchial carcinoma. Tuberculosis is more likely to make him febrile. The X-ray appearances are usually different, but may be identical.

BRONCHOSCOPY. If possible, do this as in Section 25.12. Its indications are: (1) A patient with haemoptysis in whom AAFB cannot be found. (2) Other suspicious cases (see above). The number of patients you will be able to bronchoscope will depend on your workload, and the local incidence of carcinoma of the bronchus, compared with the conditions that simulate it. In Europe, an unresolved pneumonia is likely to be due to a bronchial carcinoma causing obstruction. In much of the developing world, it is more likely to be due to a partially treated pneumonia, not associated with carcinoma.

OPERABILITY. The most favourable cases are those with a peripheral ''coin-like' lesion (usually an adenocarcinoma, sometimes a tuberculoma, or a developing lung abscess). Refer these for thoracotomy. Signs of inoperability include: involvement of the chest wall, involvement of the laryngeal or sympathetic nerves (Horner's syndrome), widening of the mediastinum in a chest X-ray, secondary deposits (as in the cervical nodes), bony secondaries, and an oat cell tumour on biopsy.

Bronchoscopic signs which suggest that a patient is not operable include: widening or flattening of the first 1.5 cm of his main bronchus, widening of his carina, and distension of his trachea.

CHEMOTHERAPY has a low priority if drugs are scarce. If he has an oat cell carcinoma, it will give him a remission and prolong his life for 6 to 12 months. A few patients with oat cell tumours survive much longer. Untreated, patients are likely to die in 2 months. Chemotherapy can also be used with other histological types of tumour, but with a much lower response rate.

Consider giving him cyclophosphamide 1 g/m['2] intravenously and vincristine 1.4 mg/m['2] intravenously, with tablets of methotrexate 15 mg/m['2] orally daily for 3 or 4 days, or, Doxorubicin (''Adriamycin') 60 to 75 mg/m['2] (32.2). Repeat this every 3 weeks for 3 or 4 months, provided the tumour is responding.