The global burden of cancer continues to increase largely because of an increasing adoption of cancer-causing behaviors, particularly adoption of cancer-associated lifestyle choices including smoking, physical inactivity, and “westernized” diets in economically developing countries. Lung cancer has remained the most common cancer worldwide for several decades and represents 12.9 % of all new cancers [1]. It is also the most common type of cancer in men and remains the most common cause of cancer-related mortality in both sexes [2]. It accounts for one of every five cancer deaths. Most patients with lung cancer present with advanced disease [3]. Although the cancer incidence rates in India are lower than in the developed world, the relative mortality rates are higher, and this disparity results in a significant contribution to the world cancer deaths. Delay in diagnosis and inadequate, incorrect, or suboptimal treatment (due to lack of access to specialist care, financial constraints, or lack of awareness) are the chief factors leading to poor cancer survival in India. In women, the incidence rates are generally lower than in men, and the geographic pattern is somewhat different, depending on the uptake and consumption of tobacco.

Registration and notification of cancer in general and lung cancer in particular are poor in most of the low- and middle-income countries (LMICs) in Asia and in Pacific Island countries, so the true incidence may still be high and underestimated. A substantial proportion of the worldwide burden of cancer could be prevented through the application of existing cancer control knowledge and by implementing programs for tobacco control.

The major histological types of lung cancer include squamous cell carcinoma (SqCC), adenocarcinoma (ADC), and small cell lung cancer (SCLC). In the recent past, a relative increase in the incidence of ADC has been witnessed. In most of the countries, it has become the dominant histological type of lung cancer [4]. This histological shift (increase in the incidence of adenocarcinoma) has been linked to changes in the smoking behavior of the population in these regions as well as in the method of manufacturing (use of filtered cigarettes) and composition of cigarettes (higher levels of nitrates) being marketed therein [5].

Most patients with lung cancer present with symptoms related to the intrathoracic spread of the tumor. The most common presenting symptoms include cough, followed by dyspnea, chest pain, and hemoptysis. A majority of them would also have significant constitutional symptoms (loss of weight ad anorexia). In addition to these, the patients may have symptoms related to the underlying comorbidities (chronic obstructive airway disease and coronary artery disease). Symptoms which would increase the probability of a malignant etiology include mediastinal symptoms (superior vena cava syndrome, hoarseness of voice, dysphagia, and Horner’s syndrome), metastatic symptoms (bony pains, lymph node swellings, and neurologic symptoms), or paraneoplastic syndromes. Less than 10 % of the lung cancer patients are asymptomatic at presentation.

In addition to detailed clinical history and examination, appropriate investigations need to be performed to confirm the diagnosis of malignancy, accurately subtype the lung cancer, and determine the stage of the disease. It is of utmost importance to get a confident pathologic diagnosis of lung cancer before any therapeutic decisions are taken. Depending on the clinical presentation and the radiologic pattern, any one of the following techniques can be used to get a tissue sample for histological or cytological examination – endobronchial biopsy, transbronchial lung biopsy, bronchoalveolar lavage, sputum cytology, pleural fluid cytology, pleural biopsy, transthoracic needle aspiration/biopsy, transbronchial needle aspiration, and peripheral node biopsy. The clinicians should ensure that while procuring sample for tissue diagnosis, enough tissue is available for immunohistochemical/molecular testing as well. Once a tissue diagnosis of lung cancer is established, an accurate staging of the tumor has to be done as per the new TNM system (seventh edition) [13].

The T stage of the tumor is primarily assessed on the CT scan of the chest. However, a fused PET/CT scan is more accurate than chest CT in accurately determining the T stage (82 % vs. 68 %) [14], as it is more accurate in delineating the chest wall/pleural invasion and differentiating distal collapse from the mass per se. An accurate N staging is very important as tumors with N2 or N3 disease are generally considered unresectable. The noninvasive modalities for assessing the N staging (including the chest CT and PET scan) are inaccurate. In the developing world, the mere presence of nodes >1 cm on chest CT or the presence of an SUV of >2.5 does not necessarily imply nodal spread of disease as they can also be due to infections like tuberculosis which are endemic in these countries. It is always preferable to use invasive modalities to confirm the tumoral involvement of lymph nodes.

The invasive modalities of nodal staging can be further classified as surgical procedures (mediastinoscopy and mediastinal lymphadenectomy) or endosonographic procedures (endobronchial ultrasound (EBUS)- or endoscopic ultrasound (EUS)-guided TBNA). The procedure chosen would depend on the availability of the equipment, technical expertise, and patient preferences. Complete medical mediastinoscopy (EBUS + EUS-guided TBNA) has been shown to have sensitivity better than that of mediastinoscopy (85 % vs. 79 %) [15]. For determining the M stage of the disease, the ideal investigation is a whole-body PET scan. However, it needs to be performed to search for occult metastatic disease only in patients who are being treated with a curative intent. A brain MRI is however superior to PET scan for detecting metastases to the brain.

The various modalities used for the treatment of patients with lung cancer include:

These modalities are used in isolation or in combination. An ideal management of patients with lung cancer requires a multidisciplinary approach – pulmonary physician, radiologist, radiation therapist, thoracic surgeon, histopathologist, and medical social worker. The treatment of NSCLC depends on the stage of the disease.