Staging is a way of describing where the cancer is located, if
or where it has spread, and whether it is affecting the
functions of other organs in the body. Doctors use diagnostic
tests to determine the cancer's stage, so staging may not be
complete until all the tests are finished. Knowing the stage
helps the doctor to decide what kind of treatment is best and
can help predict a patient's prognosis (chance of recovery).
There are different stage descriptions for different types of
cancers. The most commonly used staging system for thymoma is
called the Masaoka system, and it classifies thymoma into the
following stages: Stage I: The cancer is limited to the thymus
and the capsule that surrounds it. Stage II: The cancer has
spread into fat surrounding the thymus or into the lining of the
lung next to the tumor, called the mediastinal pleura. Stage
III: The cancer has spread to other organs near the thymus, such
as the lung, blood vessels, and the sac around the heart, called
the pericardium. Stage IVA: The c