What's new in the treatment of osteosarcoma?
Much research on osteosarcoma is now being conducted in many medical centers, university hospitals, and other institutions around the world.
New in understanding osteosarcoma cells
Researchers are learning more about what makes osteosarcoma cells different from normal bone cells. Learning more about changes in the cells of osteosarcoma may eventually lead to specific treatments based on these changes.
To name a few, researchers have found that osteosarcoma cells often have large amounts of a substance called GD2 on their surfaces. Drugs that target GD2 are already being used to treat neuroblastoma (another cancer often seen in children).
Newer immunotherapies that target the GD2 receptor are being studied for use in the treatment of osteosarcoma as well (see below).
Laboratory testing of genetic changes within osteosarcoma cells may help predict the behavior of each tumor, such as how it will respond to certain types of chemotherapy or targeted therapy drugs. This type of test is now being studied in clinical trials.
What is new in the treatment of osteosarcoma?
Significant progress has been made in the treatment of osteosarcoma in the past few decades. However, more research is needed to learn how best to manage difficult-to-treat osteosarcomas, such as those that have already spread when they are detected.
Several clinical trials focus on treating osteosarcoma using a variety of strategies.
new in Osteosarcoma surgery
The growth and spread of osteosarcoma is now better understood than it was previously.
Thus, modern imaging devices can better determine the extent and extent of tumors.
- These devices, combined with sophisticated computer software that helps surgeons determine the best surgical approach to take before and during an operation (commonly called computer-assisted oncologic surgery, or CATS), can help surgeons remove cancer while sparing as much as possible. possible from natural tissues.
- Some new types of internal prostheses can now be extended and increased in size without the need for further surgery.
This is especially important for children who, in the past, often required several operations to replace the prosthesis with a larger one as they grew up.
New in radiotherapy
Osteosarcoma cells are not easily killed by radiation, so high doses of radiation are needed to have an effect on sarcoma cells.
Because high doses can often cause unwanted side effects, this limited the use of radiotherapy for a period of time.
Today, newer forms of radiation allow doctors to focus the beams more precisely on the tumor. So that it reduces the rays that reach the nearby healthy tissues by using focused rays on the tumor itself.
Intensity-modulated radiation therapy (IMRT) is an example of an advanced form of radiotherapy. In this technique, radiation beams are formed to fit the size of the tumor and direct it at it from several angles.
The intensity (strength) of the beams can also be adjusted to limit the dose reaching the surrounding normal tissue. Many hospitals and cancer centers now use brachytherapy (IMRT), especially for tumors in areas that are difficult to treat surgically such as the spine or pelvis (hip bones).
Stereotactic radiosurgery SRS is done by giving a large dose (usually one time) of radiation very intensely to the area of the tumor.
Once the imaging tests show the exact location of the tumor, a very thin beam of radiation is focused on the tumor from several different angles.
The radiation is very precisely directed so that it has the least possible impact on nearby tissues. Doctors sometimes give radiation in several smaller treatments to deliver the same dose or a slightly higher dose. This is called fractionated stereotactic radiotherapy.
Another, newer approach is to use radioactive particles instead of x-rays to deliver radiation. One such example is Proton conformational radiotherapy, which uses positive parts of atoms.
Unlike X-rays, which release energy before and after hitting their target, protons cause minimal damage to the normal tissue they pass through and then release their energy after a certain distance. Doctors can use this property to deliver more radiation to the tumor and reduce damage to surrounding normal tissue.
Proton beam therapy may be useful for hard-to-treat tumors, such as those of the spine or pelvic bones, but only a limited number of centers offer this treatment at this time.
There is a newer approach being used carbon ions, which are heavier than protons and cause more damage to cancer cells. This treatment is still in the early stages of development and is only available in a few centers around the world.
Doctors are also studying new forms of radioactive drugs to treat osteosarcoma that has spread to many bones. One such example is radium-223 (Xofigo), which works a little differently than other radioactive drugs in use now.
New in chemotherapy for the treatment of osteosarcoma
Clinical trials are conducted to determine the best combination of chemotherapy drugs, as well as the best time to give them. The latest chemical drugs are also being studied.
The lungs are the most common place for osteosarcoma to spread. Oral inhaled forms of certain chemo drugs (such as cisplatin) are being studied for patients whose cancer has spread to their lungs.
Other forms of treatment
Chemotherapy drugs are often helpful in treating osteosarcoma, but sometimes they don't work, or the cancer becomes resistant to them over time. Researchers are studying new types of drugs that attack osteosarcoma cells in different ways.
Clinical trials are looking at ways to help a patient's immune system recognize and attack osteosarcoma cells. For example:
- Medicines that are called help Immune checkpoint inhibitors Sometimes the body's immune system begins to recognize and attack cancerous tissue. These drugs are useful against many types of cancer, and some of these drugs are now being studied for use against osteosarcoma.
- An experimental immune-stimulating drug called muramyl tripeptide (also known as MTP or mifamurtide) has been shown to extend the lives of some patients when added to chemotherapy.
- Monoclonal antibodies They are man-made versions of immune system proteins that bind to a specific target in the body, and which can help the immune system find and destroy cancer cells. Antibodies directed against GD2 and other substances on osteosarcoma cells are now being tested in clinical trials.
Researchers are now studying a new form of immunotherapy known as CAR-T cell therapy to treat osteosarcomas that no longer respond to other therapies.
Targeted therapy drugs
Doctors are also studying new drugs that target specific molecules on or within cancer cells. These therapies are known as targeted therapies.
The monoclonal antibodies discussed above may also be considered a type of targeted therapy. These antibodies attach to certain substances on cancer cells, which may kill them or help stop their growth.
An example is dinutuximab (unitoxin), which is an antibody that binds to GD2, a substance important for the growth of cancer cells.
Several other targeted drugs are being studied for use against osteosarcoma, including drugs that affect the tumor's ability to make new blood vessels, such as sorafenib (Nexavar), pazopanib (Votrient), lenvatinib (Lenvima) and cabozantinib (Cabomitex).
Medicines that affect the bones
Medications that target bone cells called osteoclasts may also be useful against osteosarcoma:
Bisphosphonates It is a group of medicines already used to treat osteoporosis (thinning of the bones) and some types of cancer that have spread to the bones. Some of these drugs, such as pamidronate and zoledronic acid, are now being studied for use in osteosarcoma as well.
denosumab It is a monoclonal antibody that targets the RANKL protein, which normally helps bone growth. It is now being studied for use against osteosarcoma.