Alkylating Agents for Breast Cancer

Medically Reviewed by Melinda Ratini, MS, DO on April 25, 2024
4 min read

If you’ve been diagnosed with breast cancer, your doctor may recommend chemotherapy. There are several types for treating breast cancer. Alkylating agents are one of them.

Alkylating agents were among the first anti-cancer drugs and are the most commonly used. They’re designed to stop cells from copying themselves. Alkylating agents do this by attaching to the cell’s DNA and stopping the cells from multiplying. The drugs target rapidly dividing cancer cells, slow down cell growth, and kill them in a process called apoptosis.

The agents are cell-cycle phase nonspecific. This means they can kill the cell in various and multiple phases of its life cycle. Alkylating agents can be used for most types of cancer, but they seem to be most effective against slow-growing cancers.

You can take them as a pill or get them through an IV in one of your veins. Your doctor may combine them with other chemo drugs.

Alkylating agents are generally divided into six groups:

Nitrosoureas (carmustine, lomustine, streptozocin) are a special kind of alkylating agent. Unlike most drugs, they’re able to cross the blood-brain barrier. That’s a specific area in the brain that keeps out most drugs.

Nitrogen mustards, along with ethylenamine and methylenamine derivatives, are commonly used with other chemo medications to treat various stages of breast cancer.

These include:

Cytoxan. The chemical name for this nitrogen mustard is cyclophosphamide. You take it in combination with other chemo drugs. You’ll get it as a pill or through an IV in one of your veins.

Cytoxan is typically used to:

  • Stop early-stage breast cancer from coming back after surgery or other cancer treatments
  • Shrink advanced-stage breast cancer tumors before surgery
  • Treat advanced-stage breast cancer after surgery and other treatments

Thiotepa. This ethylenamine and methylenamine derivative is usually given through an IV in your vein. It’s typically used after surgery and other treatments to:

  • Lower the risk of early-stage breast cancer coming back
  • Treat advanced-stage breast cancer

Carboplatin. It’s the only platinum-based antineoplastic drug approved for use against breast cancer. Carboplatin is used to treat advanced-stage breast cancer and is usually given in combination with other chemo medicines. Carboplatin is given through an IV.

The main issue with alkylating agents (and other chemo drugs) is that they can’t tell the difference between healthy cells and cancerous ones. This can lead to several side effects. Common ones are:

  • Nausea
  • Fatigue
  • Vomiting
  • Loss of appetite
  • Weight loss
  • Stomach pain
  • Diarrhea
  • Hair loss
  • Sores on the mouth or tongue
  • Changes in skin color
  • Changes in fingernail and toenail color or growth
  • Low white blood cell count
  • Irregular periods

Signs of serious reactions or side effects can include:

  • Sore throat, fever, chills, or other signs of infection
  • Wounds that are slow to heal
  • Unusual bruising or bleeding
  • Black, tarry stools
  • Pain when peeing or bloody pee
  • Rashes and hives
  • Itching
  • Difficulty breathing or swallowing
  • Shortness of breath
  • Cough
  • Swelling in the legs, ankles, or feet
  • Chest pain
  • Yellowing of the skin or eyes

Call 911 or head to a hospital right away if you have:

In rare cases, alkylating agents can damage bone marrow cells, which are responsible for making new blood cells. This can lead to leukemia, a type of cancer that affects blood-forming tissues. The higher the drug dose, the higher your chances of getting it. The risk for leukemia is highest 5-10 years after treatment with alkylating agents. Before you start the treatment, ask your doctor about steps you can take to lower the risk of developing second cancer.

Follow your doctor’s instructions closely, especially if you’re taking an oral pill. lf you forget to take a dose, continue with your next dose. Don’t double up on the pills to make up for the missed one. Talk to your doctor before stopping treatment.

You or your doctor can report serious side effects online or by phone to the FDA’s MedWatch Adverse Event Reporting program.

Alkylating agents are powerful drugs. So it’s important to tell your doctor about your medical history in detail. This helps them tailor treatments to your specific needs and minimize side effects.

Here are a few things you should mention:

  • Any allergies you may have
  • Vitamins, supplements, or herbs you may be taking
  • Kidney or liver problems
  • Previous chemotherapy treatments or recent x-rays
  • If you’re pregnant, breastfeeding, or planning to become pregnant
  • Any plans to have surgery