Neoadjuvant vs. adjuvant therapy: What is the difference?
Neoadjuvant therapy encompasses all treatments that are administered before the primary cancer treatment, whereas adjuvant therapy describes regimens administered after the primary treatment.
The overall goal of these multimodal treatment approaches is to increase the effectiveness of local definitive therapy, as well as to minimize the adverse effects patients experience during primary treatments.
This approach is most often used in patients with breast, colon or lung cancers to increase the likelihood that all cancer cells — including those that exist in distant tissues or may not necessarily be visible — are treated.
One example of neoadjuvant therapy is radiation therapy, which can be used to shrink a tumor before the patient undergoes surgery.
Chemotherapy also can be administered in the neoadjuvant setting. Women with inoperable breast cancer may undergo neoadjuvant chemotherapy in hopes that it shrinks the tumor so it can be surgically removed, sparing the patient from having to undergo a mastectomy.
Another example of neoadjuvant therapy is hormone therapy. It is often used in patients with breast cancer, as well as for men with prostate cancer.
In some cases, clinicians pursue neoadjuvant therapy when the primary local therapy is associated with a long or difficult recovery, creating a situation in which it can be challenging to administer additional treatment.
Adjuvant therapy is most often administered to patients with early-stage cancers who undergo surgery. However, it also can be administered to patients who undergo radiation as primary treatment.
The goal is to maximize the effectiveness of the primary treatment in hopes of extending survival and reducing the risk for recurrence.
The types and extent of adjuvant therapy patients receive vary, and they often are dependent upon the cancer type. Regimens may consist of a few weeks of radiation therapy, several months of chemotherapy, or many years of endocrine, hormone or molecularly targeted therapies.
A patient’s response to neoadjuvant therapy also can determine which adjuvant therapy is used.
The option of adjuvant therapy often allows the primary treatment to be performed quickly. If a tumor is removed during surgery, physicians know the tumor’s exact stage, location and molecular features, as well as the extent to which the cancer has spread.
Specific hormone receptors or mutations can be discovered after surgery, thereby determining which type of adjuvant therapy may be most effective.
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