Thoracic and lung cancer

Risk factors

Tobacco smoking is undoubtedly the main risk factor for lung cancer: it is involved in 85% of cases in men and 70% of cases in women. Environmental factors also play a role: some cancers are caused by exposure to asbestos or radon, a radioactive gas emanating from the ground that can stagnate in poorly ventilated homes. The best way to minimize the risk of lung cancer is not to smoke.

Symptoms

Symptoms of lung cancer are often delayed and sometimes misleading. They may include an increase in symptoms usually attributed to smoking, such as coughing or difficulty breathing. The occurrence of bloody sputum is often a worrying symptom. In the early stages, there is no change in the general state. Lung cancer is often discovered incidentally, during a radiological examination.

Diagnosis

Tumor biopsy is essential to confirm and clarify the precise type of lung cancer. Molecular analysis is also needed to influence the choice of potential systemic treatment, such as anti-tumor immunotherapy or targeted therapies. In addition, an extension workup should be performed to determine whether the tumor is localized, locally advanced, or already metastatic at the time of diagnosis. The choice of the best treatment is based on the combination of these two information (subtype of cancer and stage of the disease).

Screening

Ongoing studies are evaluating the value of screening by chest CT in at-risk subjects (smokers aged 55 to 75 years). An American study has shown a 20% reduction in lung cancer mortality with an annual low-dose CT scan for 3 years. As a corollary, many benign lesions are discovered which trigger unnecessary examinations (false positives). Although it is proposed to smokers in the USA, CT scan screening is not (yet) recommended in Europe. This underlines once again the importance of smoking prevention.

Examinations

Major advances have been made in the diagnostic approach to lung cancer. The most modern imaging techniques are extremely efficient and make it possible to define very precisely the extension of the tumor, and therefore to treat it appropriately. PET scan is a good example. At the Cliniques Universitaires Saint-Luc, it is performed in conjunction with CT scan (combined PET-CT), which further increases the diagnostic accuracy. Bronchial echo-endoscopy can also be used to assess the degree of extension of the tumor, particularly in the mediastinal lymph nodes.

High-performance, minimally invasive imaging techniques make it possible to accurately assess the extent of the tumor and choose the most appropriate treatment.

Treatments

The treatment of lung cancer depends on the histological type and stage of the disease..

Some cancers limited to the lung are treated with surgery. This aims to completely resect the tumor. These early stages have a good prognosis, which can be further improved in some circumstances by postoperative chemotherapy (large tumor and/or lymph node invasion). The procedure usually involves the removal of a lobe of the lung, or more rarely the entire lung. In patients with impaired lung function due to smoking, the extent of the resection may have to be limited, requiring complex and delicate procedures, such as reimplantation of bronchi after resection of a central tumor. Stereotactic radiotherapy is gaining recognition for small peripheral tumor lesions.

When the disease has locoregional extension but has not yet metastasized at distance, the treatment is multimodal, which means that it includes both chemotherapy and radiotherapy. In some cases, this combined treatment can be completed by antitumor immunotherapy. Finally, extensive or metastatic forms of the disease are treated with a "systemic" therapy, i.e. acting everywhere in the body. Traditionally, this has involved cycles of cytotoxic chemotherapy administered intravenously, but in recent years two additional modalities have supplanted chemotherapy in a growing number of indications. Targeted therapies (most often in the form of tablets taken continuously) are so named because they act directly on the tumor without having the adverse effects of conventional chemotherapy. They can only be employed if a specific target is identified, such as an activating mutation in EGFR, a receptor mutated on the surface of cancer cells. This applies to about 15% of patients. Antitumor immunotherapy is increasingly used as an alternative to cytotoxic chemotherapy, as ongoing studies confirm its effectiveness. It is based on monoclonal antibodies that are injected intravenously every 2-3 weeks and that stimulate our immune system (cytotoxic lymphocytes) to recognize and specifically destroy cancer cells. This avoids the adverse effects of cytotoxic chemotherapies (bone marrow, hair loss, etc.).

These studies take place in reference institutions. Our center participates in these studies in collaboration with other hospitals in Europe and the United States.

Small cell cancer is treated primarily with chemotherapy, sometimes in combination with radiation therapy. Surgery is very rare for this type of cancer. Anti-tumor immunotherapy is also being developed for this subtype of cancer.