Answer:

The initial presenting symptoms in patients with lung cancer are constitutional and nonspecific, mainly related to metastatic disease. Nonproductive cough, dyspnea, hemoptysis, and chest pain, along with an unresolved lung infiltrate on chest radiography, should suggest carcinoma. In the attempt to make an early diagnosis, the American Cancer Society has issued preliminary guidelines for screening high-risk patients using low-dose computed tomography (LDCT) imaging. Recommended candidates include subjects aged between 55 and 77 years with a smoking history of at least 30 packs per year, who are current smokers or quit within the past 15 years. The main limitation of this test is the 23.3% incidence of false-positive results, which may lead to further testing including surgical biopsy. Biomarkers from large airway epithelial cells or buccal mucosal biopsies are being investigated and may represent early diagnostic options in the future. Currently, the initial diagnosis and staging are done in the operating room and include flexible bronchoscopy with airway washings and brush biopsy, possibly followed by ultrasound-guided transbronchial biopsy (endobronchial ultrasound [EBUS]) for mediastinal lymph node biopsy. Additional areas for biopsy include palpable lymph nodes in the neck or axilla, needle aspiration biopsy, cervical mediastinoscopy, and possibly exploratory thoracoscopy or thoracotomy. An extensive evaluation must be performed to exclude metastases that would contraindicate major surgery.

Cancers of the lung account for 12% of all malignancies and nearly 18% of cancer-related deaths worldwide. Bronchogenic carcinomas are the most common tumors requiring surgical resection and can be classified into four major types: small cell, large cell, squamous cell, and adenocarcinoma. For surgical purposes, lung tumors are classified as non-small cell or small cell. The former is amenable to surgical resection, whereas the latter tends to be nonresectable and is medically treated.

Further subclassification of lung tumors involves the TNM classification in which T designates tumor site, size, and local extent; N the presence and location of regional lymph node involvement; and M the presence of distal metastases beyond the ipsilateral hemithorax. This system is used for staging bronchogenic carcinomas and helps predict the response to therapy. In general, small cell carcinomas that have spread beyond possible resection by the time of presentation are primarily managed with chemotherapy, with or without radiation, and are associated with a 5-year survival of approximately 20%. In contrast, non-small cell cancers found to be localized at the time of presentation should be considered for primary resection. The 5-year survival can be as high as 85% for small tumors without regional lymph node involvement or metastases (stage I). Approximately 45% of patients present with circumscribed extrapulmonary disease or lymphatic spread to the ipsilateral mediastinal or subcarinal lymph nodes (stage IIIa). Their 5-year postresection survival is less than 20%.

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