NCCN Guidelines for Patients
Stomach Cancer, Version 1.2016
1 Stomach cancer basics
Cancer cells don’t behave like normal cells in three
key ways. First, mutations in genes cause cells to
grow more quickly and live longer. Normal cells grow
and then divide to form new cells when needed. They
also die when old or damaged as shown in
In contrast, cancer cells make new cells that aren’t
needed and don’t die quickly when old or damaged.
Over time, stomach cancer cells form a mass called
the primary tumor.
The second way cancer cells differ from normal
cells is that they can grow into nearby tissues. If not
treated, the primary tumor can extend beyond the
wall of the stomach and into nearby structures. The
nearby structures into which stomach tumors grow
are described in
Part 2 Cancer staging.
Third, unlike normal cells, cancer cells can travel
to other parts of the body. This process is called
metastasis. In this process, cancer cells break away
from the tumor and merge with blood or lymph. Then,
the cancer cells travel in blood or lymph through
vessels to other sites. In other sites, the cancer cells
may form secondary tumors, replace many normal
cells, and cause major health problems.
Illustration Copyright © 2016 Nucleus Medical Media, All rights reserved.www.nucleusinc.com
Normal cell growth vs.
cancer cell growth
Normal cells increase in number
when they are needed and die
when old or damaged. In contrast,
cancer cells quickly make new
cells and live longer because of
abnormal changes in genes.