What is Lung Cancer?
Our body consists of organs and these in turn by a group of cells, which are divided on a regular basis to replace aging or dead and thereby maintain the integrity and smooth functioning of various organs. This process is regulated by a number of mechanisms that tell the cell when to start to divide and when to remain stable.
If these mechanisms are altered in a cell, it and its offspring begin uncontrolled division that eventually will lead to a tumor or nodule. When these cells grow uncontrollably also acquire the ability to invade surrounding tissues and organs (infiltration) and to move and grow in other parts of the body (metastasis) is called a malignant tumor, which is what we call cancer. When the tumor cells ability to invade surrounding healthy tissues and reach distant organs and implant in them are located in the lung, we talk about lung cancer.
This malignant tumor can grow in three ways:
Local growth: the local growth is caused by deep invasion through the lung wall (inside out). It can affect surrounding structures, which will differ depending on the location of the tumor in the lung (central or peripheral upper or lower). So that may affect the heart, great vessels, esophagus, or vertebral bodies.
Lymphatic spread: this is done via the lymph. When tumors are located in the middle and lower thirds of the lungs are affected mainly the mediastinal lymph nodes (anatomical area situated between the two lungs where structures are as important as the heart, trachea, esophagus, and large vessels). When tumors are located in the upper third, the most affected are lymph supraclavicular (above the collarbone).
Hematogenous spread: This spread is through blood vessel, preferably to the liver, adrenal glands (located above the kidneys), brain and bones.