Chemotherapy (chemo) is a type of cancer treatment. It works by killing cancer cells or reducing their growth.

There are many types of chemo drugs. Sometimes, more than one chemo drug is given to treat cancer. This is called combination chemo.

FLOT is a type of combination chemo that’s used for some types of cancer. Keep reading to learn more about FLOT, its uses, side effects, and more.

FLOT is a combination of four drugs:

5-FU, oxaliplatin, and docetaxel are all different types of chemo drugs. Leucovorin is a drug that helps 5-FU work more effectively.

FLOT is typically given both before and after cancer surgery. This is called perioperative chemo. The term “perioperative” means around the time of surgery.

The cycles of FLOT before surgery can help shrink the tumor before the procedure. Meanwhile, the cycles after surgery can help kill any cancer cells that remain.

FLOT is used for a few different types of cancer. These are:

Generally, FLOT is used for people with localized cancers that may be treated surgically. These people must also be healthy enough to tolerate combination chemo.

In comparison to many other cells in your body, cancer cells grow and divide rapidly. Chemo drugs work by targeting cells that are growing quickly. As such, it can kill cancer cells, or at least slow down their growth.

Different types of chemo drugs work in different ways. Each component of FLOT has a different role in treating cancer.


5-FU is a type of chemo drug called an antimetabolite. These drugs replace the normal building blocks of DNA, disrupting DNA replication. Because DNA replication is necessary for a cell to divide, the cell cannot do so and eventually dies.


Leucovorin isn’t a chemo drug. In fact, it’s similar to folic acid, an important vitamin. Leucovorin helps 5-FU bind to an enzyme on the cancer cell to help it work more effectively, and stay in your system longer than it normally would by itself.


Oxaliplatin is a type of chemo drug called an alkylating agent. Alkylating agents work by damaging the DNA in cells. This prevents a cell from dividing, so the cell eventually dies.


Docetaxel is a type of chemo drug called a plant alkaloid. Plant alkaloids work by blocking the process that cells use to divide into two separate cells.

It’s possible you may receive FLOT at:

  • a hospital as an inpatient, meaning you’ll stay at the hospital overnight
  • an outpatient facility (which means you’ll go home afterward), such as a:
    • hospital
    • clinic
    • doctor’s office

Before treatment

Before your treatment, a healthcare professional will collect a blood sample. It’s used to look at blood cell levels, kidney and liver function, and other markers of health. It helps your treatment team know you’re healthy enough to receive chemo.

It’s possible you may experience nausea while you’re getting your treatment. To help reduce the likelihood of this, your care team will give you an anti-nausea medication before your treatment starts.

During treatment

FLOT is given directly into your bloodstream (intravenously). Chemo is often given through a thin, soft tube called a catheter that goes into a large vein close to your heart. This can be set up in a few different ways:

  • Central line: A central line enters your body at the center of your chest. It runs under your skin and into a large vein in your chest. A small length of the line will be left outside of your chest.
  • PICC line: PICC stands for peripherally inserted central catheter. In this case, the catheter is placed into a vein in your arm and is then run up to a large vein in your chest. A small bit of the catheter will be visible on the outside of your arm.
  • Port: A port is actually a type of central line. However, instead of having a small length of line outside your chest, you’ll have a chamber called a port placed under your skin. Your medications are injected into this port.

It’s also possible you may be given FLOT through an IV. This is a short tube that’s inserted into a vein in your hand or arm when you go in for your treatment.

Central lines, PICC lines, and ports can stay in place for a longer length of time. This means your treatment team won’t need to insert a new IV every time you come in for chemo.

Chemo, including FLOT, is given in cycles. One cycle consists of a period of active treatment followed by a period of rest. The rest period allows your body to recover from the effects of the chemo.

On the day you receive your chemo, each drug is given for a set amount of time:

  • 5-FU: 24 hours
  • Leucovorin: 2 hours
  • Oxaliplatin: 2 hours
  • Docetaxel: 1 hour

It’s possible the 5-FU will be given using a pump that’s connected to your catheter line. You can typically wear this home with you, although you may need to return to the hospital the next day to have it removed.

A cycle of FLOT lasts 14 days. You’ll start the chemo on the first day and finish with the 5-FU on the second day. For the next 12 days, you’ll have no treatment.

Generally, an entire course of FLOT lasts for eight cycles. You’ll have your cancer surgery in the middle, between cycles four and five. After you’ve recovered from your surgery, you’ll complete cycles five through eight.

FLOT can increase overall survival in the cancer it’s used to treat. Let’s look at what some research says.

A 2019 trial with 716 participants compared FLOT to another type of combination chemo in the treatment of stomach cancer and gastroesophageal junction cancer.

Researchers found that overall survival was higher in participants receiving FLOT. The number of serious treatment-related side effects was similar between the two groups.

Completing all cycles of FLOT, both before and after surgery, is important. A 2021 study looked into this when FLOT was used for treatment of stomach and gastroesophageal junction cancers.

In a group of 32 people, researchers found that only 34% of them completed all cycles of FLOT. An improved overall survival was seen in these people, compared with those who only had FLOT before surgery.

Chemo targets fast-growing cells in your body. While this largely affects cancer cells, it can also affect cells in other areas that grow quickly, such as in the bone marrow, hair follicles, and digestive tract.

Because of this, chemo can have a variety of side effects. The common side effects of FLOT include:

Signs of an allergic reaction and when to contact your care team

It’s possible to have an allergic reaction to one of the drugs used in FLOT. This typically happens while you’re actively receiving treatment. Your treatment team will monitor you for any signs of an allergic reaction.

Your treatment team will inform you in more detail about the side effects you may experience with FLOT and how to manage them. However, it’s important to immediately contact your treatment team if:

  • you have signs of an infection, such as fever, cough, or trouble breathing
  • your side effects don’t get better or begin to get worse with at-home management
  • your side effects are very severe
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Can certain medications interact with FLOT chemotherapy?

Some medications may interact with the FLOT drugs. Examples include but aren’t limited to:

It’s always important to give your treatment team a list of all health-related products you’re taking, including:

  • medications, both prescription and over the counter
  • supplements or vitamins
  • herbal products

Can you have FLOT chemotherapy if you’re pregnant or breastfeeding?

FLOT can be harmful to a developing fetus. As such, ask your treatment team about recommended contraceptive measures you can use during your treatment.

The drugs used in FLOT could also be passed into breast milk. Because of this, it’s generally not recommended to breastfeed while you’re receiving FLOT.

Is it OK to have vaccines if you’re having FLOT chemotherapy?

Chemotherapy can weaken the immune system. Because of this, live vaccines, like measles, mumps, and rubella (MMR) and the chickenpox vaccine, should not be given to people getting FLOT.

You’ll be recommended to get the COVID-19 vaccine and flu shot. These are inactivated vaccines and safe to use for people getting chemo. They can also protect against potentially serious infections during your treatment.

What do I need to know about DPD deficiency and FLOT chemotherapy?

Dihydropyrimidine dehydrogenase (DPD) is an enzyme that breaks down 5-FU. Some people have a deficiency of this enzyme. They’re more likely to have severe or life threatening side effects from 5-FU.

Before starting FLOT, your treatment team will test your DPD levels. If you have low levels of DPD, a reduced dose of 5-FU may be used, or another type of treatment may be recommended.

What are the alternatives to FLOT chemotherapy?

The American Cancer Society notes several other combination chemo regimens can be used for earlier stage stomach cancer. These include:

FLOT is a type of combination chemo that’s used for stomach cancer, esophageal cancer, and gastroesophageal junction cancer. It contains three chemo drugs as well as leucovorin, a drug that helps 5-FU work more effectively.

Doctors typically use this type of chemo for people with localized tumors that may be treated using surgery. You’ll usually receive half of your FLOT cycles before surgery and the other half after you’ve recovered from the procedure.

As with all chemo, FLOT is associated with a variety of side effects. Be sure to ask your treatment team about these side effects and how to manage them before starting FLOT.