Largely for these reasons, various manifestations of lung dysfunction appearing in these people, most often, did not cause concern. Such an attitude toward the first, usually the earliest, clinical signs of lung cancer is very characteristic. Their significant property with commonplace inflammatory processes occurring in the trachea and bronchi has always been convincing in the opinion of patients with lung cancer and their relatives an explanation for the malaise in the form of “acute respiratory disease”, “flu”, “bronchitis”, “exacerbation of a long-standing chronic inflammatory easy process. ” A similar complete conviction of the origin of these first, few disturbing health disorders, can also occur in some doctors if the patient seeks medical help, and is not limited to treatment using “home remedies”. The delay in timely diagnosis of lung cancer in a similar situation is most often facilitated by the fact that under the influence of anti-inflammatory drugs and even without their systematic use, disturbing manifestations of the disease disappear and patients return to their usual work and lifestyle. The subsequent, latent period of the development of the disease can last a long time — up to 1.5–2 months. Only a repeated deterioration in well-being becomes for most patients with lung cancer an occasion to see a doctor. But then, the recognition of the disease can still present significant difficulties due to the variety of its clinical manifestations and the absence of pathognomonic, characteristic only for lung cancer symptoms.

The study of the diverse symptoms of lung cancer, undertaken back in the 50s by Professor A.I. Savitsky, aimed at revealing the term “hidden course of the disease”, which is widely used and is currently used, made it possible to identify the most characteristic syndromes that distinguish lung cancer from non-specific inflammatory diseases respiratory organs, which can represent its peculiar “mask”.

When conducting a targeted examination of patients, especially a detailed clarification of the very early changes or disorders themselves, which at that time were not alarming, it is most often possible to find out that the so-called “hidden” period of the disease is much less common than is commonly believed.

The peculiarity of the pathogenesis of lung cancer determines the features of its clinical manifestations, which become clearly recognizable most often only with a significant development of blastomatous changes. This gave rise to a somewhat arbitrary basis, to distinguish separate periods in the development of lung cancer.

The first — the so-called biological period — is the time from the onset of tumor formation to the appearance of its first signs, determined only radiologically,. The second – designated as asymptomatic or preclinical period, involves the development of a still small tumor, up to 1 cm across, which can only be established radiologically. The third period of the disease is called clinical manifestations. It is characterized by the occurrence and progression of a variety of intrapulmonary, intrathoracic and extrathoracic, as well as more general disorders caused by a developing cancerous tumor in the lung. It is assumed that the first and second periods of development correspond mainly to the I-II stages of lung cancer, and the third mainly includes the advanced stages of the disease: IIIA, IIIB, IV. A study of the diverse and multifaceted manifestations of the development of the disease in patients treated in our clinic showed that often they do not fully reflect the essence of the pathological changes that had occurred by that time in the lungs and organs of the chest cavity. Even in advanced stages of lung cancer, its clinical manifestations can be very scarce and the disease can be attributed to the asymptomatic period of its development. In 40–45% of patients, the number of people treated in the clinic, the symptoms of lung cancer in the advanced stages of development were not clearly expressed, they were limited to rare complaints of moderate health problems that did not deprive them of their ability to work. Often, the attention of patients was first attracted to the occurrence of these disorders only during a focused examination conducted by clinic specialists. Such a long absence of impaired health and well-being is one of the peculiar and quite characteristic features in the clinical development of lung cancer.