Local versus systemic therapy

Local versus systemic therapy

Local therapy is intended to treat a tumor at the site without affecting the rest of the body.
Surgery and radiation therapy are examples of local therapies.
Systemic therapy refers to drugs which can be given by mouth or directly into the
bloodstream to reach cancer cells anywhere in the body. Chemotherapy, hormone
therapy, and targeted therapy are systemic therapies.
Adjuvant and neoadjuvant therapy
Patients who have no detectable cancer after surgery are often given additional treatment
to help keep the cancer from coming back. This is known as adjuvant therapy. Doctors
believe that even in the early stages of breast cancer, cancer cells may break away from
the primary breast tumor and begin to spread. These cells can't be felt on a physical exam
or seen on x-rays or other imaging tests, and they cause no symptoms. But they can go on
to become new tumors in nearby tissues, other organs, and bones. The goal of adjuvant
therapy is to kill these hidden cells. Both systemic therapy (like chemotherapy, hormone
therapy, and targeted therapy) and radiation can be used as adjuvant therapy.
Most, but not all, patients benefit from adjuvant therapy. How much you might benefit
from adjuvant therapy depends on the stage and characteristics of your cancer and what
type of surgery you had. Generally speaking, if the tumor is larger or the cancer has
spread to lymph nodes, it is more likely to have spread through the bloodstream, and you
are more likely to see a benefit. But there are other features, some of which have been
previously discussed, that may determine if a patient should get adjuvant therapy.
Recommendations about adjuvant therapy are discussed in the sections on these
treatments and in the section on treatment by stage.

Some patients are given treatment, such as chemotherapy or hormone therapy, before
surgery. The goal of this treatment is to shrink the tumor in the hope it will allow a less
extensive operation to be done. This is called neoadjuvant therapy. Many patients who
get neoadjuvant therapy will not need adjuvant therapy.