Chordomas and Radiotherapy

Radiotherapy, or radiation therapy, is commonly used to treat chordomas.

Radiotherapy uses high-energy radiation via particle beams involving photons (e.g., X-rays, gamma rays) or protons to induce damage to cancer cells while preserving healthy tissues.

Radiotherapy is usually given after surgery to inhibit the growth of any remaining cancer cells. Sometimes your doctors may recommend radiotherapy before surgery, which is called neoadjuvant radiotherapy. If the tumor cannot be treated through surgery, radiotherapy becomes the primary method to treat chordomas. Radiotherapy may also be recommended when the tumor has spread to other parts of the body (metastasized).

Radiation therapy can be delivered from outside of the body (external beam radiation therapy), or from an implant placed inside of the body (brachytherapy). External beam radiation therapy (EBRT) is the most common type of radiotherapy used to treat chordomas. It involves the use of high energy beams that target the tumor to inhibit growth. These beams often involve photons (e.g., X-rays, Gamma rays), or particles such as protons or carbon ions.

Proton and carbon-ion radiation therapies are known for their ability to target tumors with high doses of radiation while minimizing the exposure to surrounding healthy tissues. This precision is due to the unique physical properties of protons and carbon ions, which release their maximum energy at a specific point, known as the Bragg peak, directly within the tumor.

Photon beam therapies, such as conventional X-rays, can also be focused on the tumor, but protons and carbon ions offer a greater level of control, reducing the radiation dose that passes beyond the tumor. This makes proton and carbon-ion therapies particularly beneficial for treating tumors near critical structures in the body.

For chordomas, which are often situated close to vital organs and nerves, the use of proton or carbon-ion therapy can be advantageous, as it allows for aggressive treatment of the tumor while preserving as much of the normal tissue as possible. However, it is not widely available as only a limited number of centers are available around the world.

Besides the composition of the beam, radiation therapy can be further categorized by the way it is delivered and technologies used to define the target. In stereotactic radiosurgery (SRS), a large dose of radiation is delivered at the exact tumor location typically in a single session. Its name is derived from the highly precise nature of this technique but does not actually involve any incision.

SRS is often named based on the company that makes the machine. CyberKnife, Novalis, and Gamma Knife are just a few of the many SRS technologies that you may hear about at the clinic. In fractionated radiotherapy, a smaller dose is given over several shorter treatment sessions for a few weeks.

There are various types of radiation therapy systems that can aim beams from many different directions and allow the user to change the intensity of beams to provide the highest dose to the center of the tumor. This includes 3D conformal radiation therapy (3D-CRT) and intensity modulated radiation therapy (IMRT) techniques.

Whether or not you are awake during radiotherapy depends on the type of radiotherapy you are receiving and the location of the tumor. In most cases of EBRT, you will remain awake during the treatment. The treatment is typically given on an outpatient basis, which means you will come to the clinic or hospital for your treatment session and go home the same day.

During treatment, you will lie on a table and the machine will be positioned around you to deliver the radiation. Each treatment session is painless and will require you to stay as still as possible for maximal treatment benefit. While the entire session may take 20 to 30 minutes or longer, the actual duration of radiation delivery may just be a few minutes. The extra time is used to carefully plan the treatment and outline the borders of your tumor.

With brachytherapy, whether you're awake or not during the procedure depends on where the surgeons need to put the radiation source. If they need to do surgery to place the implant, you may receive medicine to make you sleepy, or you might be put to sleep completely with general anesthesia. Your surgeon will discuss options for this procedure, and they will consider what you are comfortable with.

Radiotherapy is associated with several possible side effects, which vary depending on the area being treated, the amount of radiation used, and the length of treatment. Some potential side effects of radiotherapy include:

• Fatigue, which can be caused by the treatment itself or to the body’s response to the treatment
• Skin changes, where the skin may become red, dry, itchy, or sunburned; however, this is usually temporary and can be treated with moisturizers or special creams
• Nausea, vomiting, or diarrhea
• Hair loss, although this is usually temporary
• Dental problems, radiation to the head and neck can affect saliva production and the health of teeth and gums
• Infertility, may occur especially if radiation is directed near the reproductive organs or the pituitary gland
• Long-term side effects, such as problems with memory, or rarely secondary cancers and healthy tissue death (radiation necrosis)

Not everyone will experience side effects, and in most cases, they can be managed or treated. If you are planning a baby before or during treatment, tell your doctor.

Chemotherapy is a treatment that uses medications to destroy rapidly dividing cells. This may be used in addition to surgery or radiation therapy to slow the growth of chordoma. It may also be employed when the chordoma has spread to other places in the body (metastasized).

Chemotherapy for chordomas is typically administered through a vein in the arm. The treatment is usually given in cycles, with each cycle consisting of a period of treatment followed by a period of rest. The number of cycles and the length of treatment will depend on the type and stage of the chordoma, as well as your overall health.

Possible side effects of chemotherapy vary depending on the drugs used, the intensity of therapy, and the tumor response. Common side effects of chemotherapy include nausea and vomiting, fatigue, hair loss, and an increased risk of infection. Additionally, some drugs used in chemotherapy can cause damage to the heart, lungs, and other organs, although this is rare.

Chemotherapy is not the first choice of treatments for chordomas. It is used in conjunction with surgery and radiotherapy with the hopes of achieving better tumor control, though individual response may vary. Your doctor will work with a team of other specialists to evaluate your condition and determine the most appropriate treatment plan.

Chemotherapy has traditionally been less successful in treating chordomas because these tumors tend to be resistant to the drugs commonly used in chemotherapy. However, the landscape is changing as researchers are actively testing new medications. These emerging drugs are designed to target specific pathways and mechanisms that chordoma cells use to grow and survive.

With ongoing clinical trials and research into the genetic makeup of chordomas, there is a growing optimism that more effective treatments will be developed. These advancements could provide new options for patients with chordomas, potentially improving outcomes and offering hope where the current standard treatments may be limited. It's important for patients to discuss the possibility of participating in clinical trials with their healthcare team, as this can provide access to cutting-edge therapies that are not yet widely available. Information regarding clinical trial availability can be found here.

• Radiotherapy is a treatment method that uses radiation to inhibit the growth of cancer cells.
• For chordomas, radiotherapy is usually given after surgery to prevent growth of any remaining cancer cells. If the tumor cannot be treated surgically, radiotherapy becomes the primary treatment of choice.
• Radiotherapy has several possible side effects, such as skin changes, nausea and vomiting, hair loss, and fatigue, among others.
• Chemotherapy is not very effective to control chordoma growth and is typically used when other options are not possible or have been exhausted, or following surgery and radiotherapy.

• National Cancer Institute: Chordoma
• Chordoma Foundation
• NIH Genetic & Rare Diseases (GARD) Center: Chordoma
• Cancer Net
• American Cancer Society