In a series of observations, a histological study of the structure of cancer metastasis in regional lymph nodes when comparing it with the structure of the primary tumor in the lung shows a decrease or increase in its differentiation. It can be assumed that such changes can characterize the general trends in the growth and development of a malignant tumor and affect the prognosis of the course of the disease after surgery, bringing it closer to the results of surgical treatment for undifferentiated or highly differentiated forms of lung cancer, respectively.
It is known that damage to the lymph nodes by cancer metastases is accompanied by an increase in their size, which is associated with the development of the blastomatous process. Often this external symptom serves as the basis during surgery to refuse to remove such lymph nodes and expand the scale of the operation. The results of the studies conducted in the clinic show that it is not possible to trace strict parallelism here. Despite the fact that the trend in the frequency of detection of lung cancer metastases in the lymph nodes increases with their size, even in the largest of them – over 30 mm across – blastomatous lesion was found only in 52%. In eastern observations, such an increase in nodes is due to nonspecific changes. At the same time, in the lymph nodes of a small size — 15— mm in diameter — every tenth (10.7%) contained cancer metastasis. That is why when deciding on the prevalence of lung cancer, the stage of development of this disease, the choice of the scope of surgical intervention, especially during the revision of the mediastinum, the study of outwardly unchanged, unexpanded lymph nodes should be given no less attention than enlarged,
forming large conglomerates. The location of the tumor in the peripheral or central parts of the lung does not significantly affect its biological characteristics, the tendency to lymphogenous metastasis in regional collectors. Meanwhile, the limited local growth of the primary tumor with its peripheral location in the lung, often at a considerable distance from large vessels, even at far advanced stages of the development of the disease, determines the technical availability of partial resection. Moreover, the removal of regional lymphatic collectors is often not undertaken, and it is assumed that the performed volume of surgical intervention for cancer reasons is quite radical.
A detailed study of the characteristics of lymphogenous metastasis of peripheral and central cancers, a comparison of the nature and degree of damage to regional collectors throughout — from the intrapulmonary to the mediastinal and supraclavicular divisions of them convincingly shows that there are no differences for each of these two forms of their growth. It is noteworthy that in patients with peripheral lung cancer, multiple metastases in the lymph nodes of the mediastinum are even more common than the central one, accounting for 82% and 51%, respectively. This is explained by the pathomorphological features of the growth of each of these two main forms of tumor growth.
Peripheral tumors are located in departments of the lung that have a particularly abundant, well-defined network of lymphatic vessels and capillaries. The numerous connections that form between the lymphatic vessels in the borderline zone of tumor growth with the adjacent parts of the lung create the most widespread opportunities for penetration into the lymphatic channel of cancer cells and their complexes — potential metastases.