Lung cancer: tools for diagnosis

Several tests are needed to confirm the cancer diagnosis and to assess how the disease has spread.

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.