Lung cancer: tools for diagnosis
Biopsies to confirm lung cancer diagnosis
If the clinical exam and the radiological exams suggest lung cancer, it is absolutely crucial to take a sample of the lesion via biopsy, to obtain histological or cytological proof.
Biopsies are performed either by bronchial fibroscopy, which involves the physician inserting a small tube into the nose or mouth, pushing it as far as the lung to reach a lesion and take a sample, or by puncturing the skin, with the radiologist inserting a needle through the skin to reach the lesion, during a scan or ultrasound. Surgery is sometimes needed to take a sample of a lymph node in the mediastinum, or to perform a lung biopsy.
The histological or cytological proof is obtained via a microscope examination of the tissues and/or cells. Additional analyses are often needed to refine the diagnosis and identify the most appropriate treatment.
The diagnosis may be one of a non-cancerous disease.
To assess how the disease has spread, imaging tests will be performed to identify all lesions present in the body, a determining factor in the subsequent establishment of the therapeutic strategy: chest scan with abdominal cross-sections including adrenal glands, a brain scan or ideally an MRI, and a PET (Positron emission tomography) exam.
Several stages in lung cancer
Following the assessment of the spread of the disease, the disease will be classified at one of 4 stages.
- Stage I: This is a localized cancer, smaller than or equal to 4cm, not affecting the regional lymph node and without metastasis.
- Stage II: This is a localized cancer, smaller than or equal to 5cm, and/or affecting the intra-pulmonary, peribronchial or hilum lymph node, but not affecting the regional lymph node, and without metastasis.
- Stage III: This is a locally advanced cancer since it has reached the mediastinum lymph node and/or has entered the mediastinum or the chest wall.
- Stage IV: This is a cancer with at least one metastasis.