Lung cancer, which now in India is recognized as a major type of common and fatal cancers, was described as ‘rare’ to “extremely infrequent” about half a century earlier. It was in 1962 when an ‘increasing trend in incidence’ was noticed in a report of 1570 cases admitted between 1955-59 in teaching hospitals of Delhi, Lucknow, Calcutta, Bombay and Madras.Sporadic reports on lung cancer thereafter appeared from different centres from India.
The diagnosis of lung cancer in the past was primarily based on clinical features supplemented with a chest radiographic examination. Histological and/or cytological diagnosis was rarely made and often considered unnecessary and/or undesirable. The approach to both the diagnosis and the treatment was generally nihilistic and dismissive. Nothing more than palliative radiation therapy was offered in most cases.
The boundary between “the Past” and the “the Present” however is unclear and arbitrary. There had been a continuous growth in prevalence reports, recognition of risk factors and advances in diagnostic and treatment modalities. Some of the important observations which were made in the 1980s related to the similarities between the contemporary epidemiology of lung cancer in India to that in the Western countries about 40 years earlier. It was commoner in males, between 4th to 6th decades of life, and with a strong smoking association.
The period around a decade before and a decade after the end of the 20th century has been significant in the overall attitude and approach to lung cancer in India. The problem was recognized and reported from several different parts of India. Most importantly, the role of tobacco smoking in causing lung cancer was firmly established and reported. The higher odds ratios of lung cancer for tobacco smoking were also reported for different forms of tobacco smoking including the cigarettes and the bidis. Passive smoking or environmental tobacco smoke exposure was also shown to increase the risk for lung cancer in women and other nonsmoker individuals.
There has been an enormous expansion and wider availability of different methods of diagnosis. The imaging modalities multiplied both in numbers and in the types of available procedures. High resolution digital radiography, computerized tomography, spiral CT scanning and magnetic resonance imaging have made it possible to diagnose the lesion more precisely. More PET scans for detection of metastases are being installed in different regions of India. Image guided fine-needle aspiration cytology helped in a more firm diagnosis of small sized and peripheral lung lesions. Similarly, bronchoendoscopic techniques for diagnosis included the introduction of trans-bronchial and trans-tracheal fine needle aspiration cytology and biopsy.
The wider application of percutaneous, bronchoendoscopic, thoracoscopic and mediastinoscopic procedures have made almost all the areas of lung approachable to obtain tissues for histo / cytological diagnosis. Endo-bronchial ultrasound (EBUS) guided fine needle aspiration is particularly helpful in lymph node staging in lung cancer. Therefore, a greater reliance is now placed on the histologically confirmed diagnosis, than the diagnosis based on only the physical and/or radiological findings.
Histological diagnosis has assumed greater importance not only to confirm the disease but also to administer a more definitive form of treatment with chemotherapy, radiotherapy and possible surgery. Attempts are now made to classify lung cancer into small cell (SCLC) or non-small cell lung cancer (NSCLC) and to stage the disease.
Although surgical resection is still rare to uncommon, the options for medical treatments have widely increased. Several newer chemotherapeutic agents and regimens have been introduced. Toxic effects with the newer agents are relatively much less. There has been a survival benefit with the introduction of more standardized regimens and other supportive care. Some other treatment options have also become available. Local brachytherapy, endo-bronchial stents for bronchial airway obstruction, targeted therapies and limited surgical approaches are also tried.
But one must admit that the cost of chemotherapy has tremendously increased which is not necessarily parallel to the increase in survival benefit. This is especially relevant in the Indian context, since a relatively poorer family may frequently find the increase in survival of the patient by a few weeks as futile after loosing the lifetime resources on treatment. The concept of ‘best supportive care’ and of ‘end of life care’ for terminal and incurable disease has found an echo in the comprehensive management plans of lung cancer. A greater stress on palliative treatment to provide symptomatic relief from intractable pain, breathlessness, sleeplessness, restlessness, anxiety and depression is considered more important than continuation of “curative” or radical treatments for the ‘end of life care’.
Some of the future developments are easier to visualize while others are difficult to imagine. There is an obvious stress on an early diagnosis. Screening of high risk populations to detect early lesions have proved to be generally futile and cost-prohibitive all over the world. But the average period from presentation to diagnosis is likely to significantly decrease with the wider and cheaper availability of radiological and bronchoscopic procedures. Research is actively ongoing in the field of identification and assessment of specific biochemical, immunological or genetic tumour markers for their diagnostic and prognostic importance. Some of the important subjects of interest in this field of early diagnosis include the use of DNA micro-arrays and proteomics, the detection of molecular targets (VEGF, FGF, MMP etc.) and parameters concerning tumour cell proliferation and apoptosis (EGFR, p53, K-ras, rb, bcl-2); and novel approaches such as the identification of cancer associated serum markers in mouse models.
From management point of angle, there are several therapeutic potentials including in India. Because of the improvements in curative resectional and reconstructive surgery, it is likely to be widely employed in management. Hopefully, a larger number of thoracic surgeons and oncologists, will opt to manage lung cancer. The advances in chemotherapy with new drugs/combinations, adjuvant CT and salvage CT will continue to occur. Tumour targeting with drugs will help more specific therapy. Other novel therapies which may find a place in the treatment include the novel pathways for immune regulation, nanotechnology and new targets e.g. angiogenesis (inhibition of mediators – VEGF).
Finally, the palliative treatment as well as the end of life care will continue to occupy an important place in the comprehensive management. This subject requires an equal or even greater attention of the oncologists, physicians, patients and their family members, and other involved partners.