NCCN Guidelines for Patients® | Esophageal Cancer - page 9

9
NCCN Guidelines for Patients
®
: Esophageal Cancer
Version 1.2013
Part 1: About esophageal cancer
Par t 1
Par t 2
Par t 3
Par t 4
Par t 5
Par t 6
Par t 7
Par t 8
1.2 How esophageal cancer starts
Cancer is a disease of cells—the building blocks of tissue in the body. Inside of
cells are coded instructions, called genes, for building new cells and controlling
how cells behave. Changes in genes cause normal esophageal cells to become
cancer cells. It is not fully understood how and why genes change and cause
cancer cells. Much remains to be learned.
Esophageal cancer most often starts in squamous and glandular cells.
Squamous cells are found in the epithelium of the esophageal wall. Cancers of
these cells are called squamous cell carcinomas. Cancers that start in glandular
cells that make mucus are called adenocarcinomas.
1.3 How esophageal cancer spreads
The changes in genes cause cancer cells to make too many copies of
themselves. Normal cells grow and then divide to form new cells when needed.
They also die when old or damaged. Cancer cells don’t do this. Cancer cells
make new cells that aren’t needed and don’t die quickly when old or damaged.
Over time, cancer cells form a mass where they started to grow. This mass
is called the primary tumor. If not treated, the primary tumor can grow large
and invade other tissues. Cancer cells can also break away from the primary
tumor, spread to other sites, and form secondary tumors. This process is called
metastasis. Secondary tumors can form in the lung, liver, bones, and other
organs.
Cancer cells spread through blood or lymph vessels. Lymph is a clear fluid that
gives cells water and food. It also has white blood cells that fight germs. After
draining from the esophageal wall, lymph travels in vessels to lymph nodes.
Lymph nodes are small disease-fighting organs that destroy the germs picked up
by lymph. Lymph nodes and vessels are found throughout the body as portrayed
in Figure 2.
Figure 2. Lymph nodes
and vessels
Illustration Copyright © 2013
Nucleus Medical Media, All rights
reserved.
1,2,3,4,5,6,7,8 10,11,12,13,14,15,16,17,18,19,...100
Powered by FlippingBook