What's the difference: Adjuvant and neoadjuvant therapies

Adjuvant and neoadjuvant therapies are treatments like chemotherapy or hormone therapy that are delivered before or after the primary treatment, to help increase the treatment's chance of success and decrease the risk of recurrence.

Fighting cancer typically involves more than one treatment. Most of the time, the disease requires a multidisciplinary approach, or a combination of therapies. Treatment plans often involve a primary therapy—generally surgery or radiation therapy—in addition to an adjuvant and/or neoadjuvant therapy. But many patients don’t know what these latter terms mean, or what purpose the treatments serve. In a nutshell, these are therapies, like chemotherapy or hormone therapy, delivered before or after the primary treatment, to help increase the treatment’s chance of success and decrease the risk of recurrence.

The word 'adjuvant' literally means helper or helping. It's essentially adding icing to the cake of the primary treatment.” - Issam Alawin, MD - Medical Oncologist at our hospital in Tulsa

Neoadjuvant and adjuvant therapies are often used to treat breast cancer, colon cancer and lung cancer, and may include chemotherapy, hormone therapy, radiation therapy, immunotherapy and targeted therapy. The two therapies differ largely in when they are given and why. Neoadjuvant therapies are delivered before the main treatment, to help reduce the size of a tumor or kill cancer cells that have spread. Adjuvant therapies are delivered after the primary treatment, to destroy remaining cancer cells.

Most often, neoadjuvant and adjuvant therapies are recommended when a patient with early-stage cancer undergoes surgery or radiation therapy and the oncologist believes he or she may benefit from additional systemic treatments—or treatments that affect the entire body, Dr. Alawin says. “Let’s say a woman comes in with localized breast cancer, and the first-line treatment in this case is surgery, but to improve the chances that the surgery works as well as it can, we give chemotherapy three or four months before surgery, or three to four months after surgery,” he says. “Many times, there is a significant improvement in prognosis and a decreased risk of recurrence with doing either an adjuvant or neoadjuvant approach.”

Neoadjuvant and adjuvant therapies benefit many, but not all, cancer patients. The type and stage of a patient’s cancer often dictate whether he or she is a candidate for additional treatment. For example, if surgery determines that cancer is found in a large number of lymph nodes, the risk rises that cancer cells may be left behind and adjuvant therapy may help. Also, because certain cancers result from specific mutations that carry a high risk of recurrence, adjuvant therapy may benefit patients with these cancers more than those with cancers that have a lower recurrence risk.

In some cases, neoadjuvant therapy may make more sense than adjuvant therapy. “If I give a breast cancer patient chemotherapy before surgery, I have the luxury of assessing the response, to see if the tumor is indeed shrinking,” Dr. Alawin says. “I can then adjust the patient’s treatment accordingly, which may mean fewer treatments. Neoadjuvant therapy may also serve as a tool for determining the patient’s response to treatment. If the tumor responds to chemotherapy before surgery, you know that the patient is more than likely to do well.”

Many times, though, both neoadjuvant and adjuvant therapies may be prescribed. An article in JAMA Oncology describes when such cases arise: “Recommendations for adjuvant therapy may be based on response to neoadjuvant therapy. For example, if the first approach was less successful than hoped, a different systemic therapy may be used for adjuvant therapy.”

It’s important to know, though, that neoadjuvant and adjuvant therapies may cause side effects, such as the nausea and fatigue that often accompany chemotherapy. That’s why they’re commonly recommended for otherwise healthy cancer patients when the expected benefits outweigh the potential risks. “It’s important to speak with your doctor about the risks versus the benefits before starting any treatment program,” Dr. Alawin says.