neoadjuvant therapy
Meaning of neoadjuvant therapy: Treatment moved to the front of the queue, shrinking a tumor before surgery and revealing in advance how it answers back.
Definition of neoadjuvant therapy
Neoadjuvant therapy is treatment given before the main treatment, which is usually surgery, in order to shrink a tumor and make the operation smaller or possible at all. Drugs, radiation, hormone treatment or a combination may be used. Because the tumor is still in place, its response can be watched, and that response carries information no other test provides.
How does it differ from adjuvant therapy?
| Timing | Name | What it aims at |
|---|---|---|
| Before the main treatment | Neoadjuvant | Shrinking the tumor and testing its response |
| After the main treatment | Adjuvant | Clearing cells that may already have spread |
| In place of surgery | Definitive or primary | Treating the disease outright |
Adjuvant means helping, so adjuvant treatment took its name from being an addition to surgery. Neo means new, and neoadjuvant describes that same helping treatment moved in front. The drugs are frequently identical and only the order changes. Because it comes first and prepares the ground for the definitive step, it counts as a form of induction therapy.
What is gained by treating first?
Three things. A large tumor may shrink enough for a lesser operation, which is how breast conservation replaces removal of the whole breast in many cases and how a rectal tumor can be taken out with clear margins. A tumor stuck to the structures around it may separate from them. And the response gives a direct readout of whether the treatment works against that particular cancer, information that is lost when the tumor is removed first. Where nothing viable remains at operation, a state called a pathological complete response, the outlook is generally better.
What is the trade-off?
Surgery is delayed, and a cancer that fails to respond grows during the wait, so response is monitored and the plan is changed if it stalls. Judging the true extent of disease afterward becomes harder, since the tumor that would have guided staging has been altered, and small markers are placed beforehand to record where it sat. Side effects of chemotherapy or radiation therapy can also complicate healing, so the interval before the operation is planned rather than incidental.
Also known as
Used in a sentence
Neoadjuvant therapy was given to reduce the tumor before resection was attempted.
Good to know
Because the tumor is treated before it is removed, the specimen no longer reflects the disease as it first presented, so staging after neoadjuvant treatment is recorded separately from the stage assigned at diagnosis.
Word origin
Where “neoadjuvant therapy” comes from
Neo- comes from the Greek neos, meaning new; adjuvant from the Latin adjuvare, to help.