In fact, patients rarely complain of breathing problems in the early stages of lung cancer, because at this point, the lesions are peripheral and not near a major airway, so there is no blockage that would cause breathlessness. Dyspnea is more often a symptom of later-stage lung cancer. Studies have shown that when patients with lung cancer begin to complain of dyspnea that is severe enough to require medical evaluation, they usually have a life expectancy of only 2 to 3 weeks. The second tumor group in which dyspnea most commonly occurs is breast cancer. In this group, breathing problems are caused by pleural effusions rather than by a blockage in the lungs.
Chemotherapy drugs can cause pulmonary toxicity and produce dyspnea.
Radiation delivered to the chest can cause pulmonary compromise, which is most problematic for patients with lung cancer. Surgical dissection for lung cancer places patients at substantial risk for dyspnea, particularly when it is performed on patients with other risk factors. When a smoker undergoes lung resection, the risk of dyspnea is increased. Another common cause of dyspnea is pulmonary embolism, she said. This condition can be the result of surgery or long-term immobility and is characterized by a slow, gradual collection of fluid.