Osteosarcoma, also known as osteogenic sarcoma, is a rare but malignant type of bone cancer. It typically affects the longest bones in the body and usually starts in the femur, humerus, and tibia.
This type of cancer, like all other bone cancers, appears due to a genetic mutation that causes a DNA change within healthy bone cells. This in turn causes the cells to believe they need to create a new bone when that in fact is not the case.
The cancer cells usually first appear between the ages of 10 and 19, when the bones grow the most – during puberty. However, even though it’s primarily found in young adults and teenagers, adults can be diagnosed with it as well, but these cases are few and far between.
Osteosarcoma is the most common type of bone cancer, but as a disease, it’s quite rare. It only accounts for 2.4% of all childhood cancers.
Nonetheless, regardless of how rare it is, it should be taken seriously which is why we prepared this in-depth explanation that covers everything you need to know about it.
Osteosarcoma can be divided into multiple different types depending on its severity and place of origin.
Low-grade, also known as central osteosarcoma, is very slow growing and is typically easy to treat. When observed under the microscope, it looks almost identical to a normal bone. This, along with the fact that low-grade osteosarcoma is extremely rare, it’s often misdiagnosed.
The subtypes of low-grade osteosarcoma include intramedullary osteosarcoma and parosteal osteosarcoma.
Certain subtypes of osteosarcoma aren’t severe enough to be classified as high-grade but also aren’t as mild as low-grade osteosarcomas, which is why they fall under the intermediate-grade category.
A type of intermediate-grade osteosarcoma is periosteal.
High-grade osteosarcomas are fast-growing and when observed under a microscope they don’t even look like normal bones. This is the most common type of osteosarcoma and therefore has multiple subtypes:
- Small cell
- High-grade surface
Localized and metastatic
When talking about the different types of osteosarcoma, we also have to mention localized and metastatic osteosarcomas.
Localized osteosarcoma is confined to the bone it first appeared in and in some cases the tissues next to said bone. Metastatic osteosarcoma on the other hand describes osteosarcoma that has spread to other parts of the body, such as other bones or organs like the lungs or brain.
Pinpointing what exactly causes osteosarcoma isn’t easy because there isn’t a clear and defining cause of this disease. However, we do know that certain changes in a person’s DNA can cause bone cells to become cancerous.
As we already mentioned, osteosarcoma is caused by a genetic mutation that is acquired during a person’s lifetime. This mutation can be caused by inherited or acquired gene changes.
Inherited gene changes can occur when one or both parents carry a cancerous gene and pass it on to their children. The two most common cancerous inherited gene changes are those that cause Li-Fraumeni syndrome as well as changes in the retinoblastoma (RB1) tumor suppressor gene.
Acquired gene changes on the other hand aren’t inherited but instead occur during a person’s lifetime, and they are the most common causes of osteosarcoma. Unfortunately, doctors still can’t pinpoint why these gene changes happen and they’re usually random events.
There are certain risk factors that can contribute to osteosarcoma, even though not everyone who falls within this category will develop the illness.
The general risk factors for this disease include:
- Age: The risk is highest between the ages of 10 to 30, particularly during adolescent growth spurts
- Height: Children who are tall for their age may be at an increased risk
- Gender: It is more common in males than females
- Race/Ethnicity: It is slightly more common in Hispanic/Latinos and African Americans
- Radiation Exposure to Bones: People who received radiation therapy for another cancer may be at an increased risk, especially if they were treated with high doses at a young age
However, additional risk factors come into play in certain cases such as:
- Specific bone diseases: People with particular types of non-cancerous bone diseases may be at a higher risk
- Paget’s Disease
- Ollier Disease
- Polyostotic Fibrous Dysplasia
- Hereditary Multiple Osteochondromas
- Inherited cancer syndromes: Specific rare genetic cancer syndromes are linked to a higher risk
- Li-Fraumeni Syndrome
- Rothmund-Thomson Syndrome
- Bloom Syndrome
- Werner Syndrome
- Diamond-Blackfan Anemia
Osteosarcoma symptoms vary from person to person, and the type of symptoms a patient will experience largely depends on the size and placement of the cancer. However, there are certain common symptoms anyone who has osteosarcoma typically experiences:
- Experiencing pain and tenderness at all times, even while resting but especially when lying down.
- Unexplained swelling in the affected area. Sometimes, the patient might also see and/or feel a lump, but this isn’t always the case.
- Having difficulty moving around and/or walking with a limp.
There are also some less common symptoms that some people experience. These include weight loss, a high temperature, and weakened bones.
If you or your child are experiencing the aforementioned symptoms and believe you may be suffering from osteosarcoma, it’s crucial to go to a medical professional as soon as possible. Once you explain your concerns, your doctor will go through all the necessary steps to get you an osteosarcoma diagnosis.
Here are all of the tests you can expect the doctor to order:
Even though a blood test can’t detect the presence of osteosarcoma or any other kind of bone tumor, it’s still usually the first step in determining whether something is wrong with the patient. This test can give your doctor insight into whether certain organs such as the liver or kidneys are working properly.
As osteosarcoma is a bone cancer, it’s vital to check for any bone abnormalities by doing an X-ray or CT scan. With these scans, your doctor can get a better view of your bones and the possible affected area to see if something looks strange or abnormal.
In some cases, an X-ray and CT scan aren’t enough because the doctor will need a more in-depth view of the area that is potentially affected. That is when they will order an MRI scan, which takes clearer images of the body by utilizing radio waves and large magnets.
One of the most surefire ways to detect any type of bone disorder is by doing a bone scan. When this test is performed, a small amount of radioactive material is injected into the patient’s body and a special camera detects where and in which capacity the material – known as a tracer – is absorbed.
If an area absorbs too much or too little tracer, that is an indication that something is wrong and some type of bone damage or anomaly is present.
All of the tests we mentioned can detect that there is some sort of issue present, but none of them can confirm a definitive diagnosis. If even one of these tests suggests the presence of osteosarcoma, your medical professional will order a biopsy.
A biopsy is a test during which a small amount of tissue is removed from the patient’s bone and then examined under a microscope. Based on the appearance and certain characteristics of the cell, the technician doing the biopsy will be able to tell whether cancerous cells are present.
After your doctor detects the presence of osteosarcoma and determines its severity and staging, they will discuss potential treatment options with you.
Chemotherapy Followed by Surgery
One of the most common ways to treat osteosarcoma is by performing surgery, but before that can be done, the patient needs to go through chemotherapy.
Chemotherapy that is given to patients before surgery is known as neoadjuvant chemotherapy and its purpose is to kill cancer cells that are going through the body and shrink the tumor. This chemotherapy usually lasts for approximately 10 weeks.
Afterward, the patient will undergo surgery during which the tumor will be cut out of the bone, along with some healthy tissue surrounding the bone. Depending on the severity of the disease and its location, amputation may be necessary, but that’s not always the case. In fact, amputation is very rare and only happens in extreme cases.
After the surgery, the patient will receive adjuvant chemotherapy for an additional 18 weeks to remove any additional cancer cells.
Another form of osteosarcoma treatment is radiation therapy, which is administered when the affected area can’t be treated with surgery. There are two types of radiation therapy: internal and external.
Internal radiation therapy involves inserting a radioactive substance, usually bone-seeking radiopharmaceuticals, via a needle or a catheter. This will deliver radiation directly to the affected area and treat the cancer site.
External radiation therapy is performed with a machine that points radiation at the cancerous areas of the body.
This form of treatment includes the use of specific drugs that block proteins that cancer cells depend on to grow and sustain themselves. This form of treatment doesn’t harm as many healthy cells as radiation therapy or chemotherapy.
Rotationplasty is a procedure that is performed only when the area of the leg located above the knee, also known as the distal femur, is affected by osteosarcoma.
During this procedure, the leg is partially amputated so the tumor can be removed. The next step is to rotate the lower leg 180 degrees, replacing the knee with the ankle, and then reattaching the leg.
In some rare cases, your doctor may suggest cryosurgery, which is a surgical procedure that involves the use of liquid nitrogen or carbon dioxide to freeze and kill cancerous cells. However, this is very rarely used as the first line of defense.
The rehabilitation process that follows osteosarcoma treatment largely depends on the type of surgery that the patient received.
Regardless of the type of surgery, every patient who was treated for osteosarcoma will need to have regular follow-up visits with their doctor to ensure their treatment was successful. These visits will often include imaging studies and/or blood tests.
The patients who unfortunately had their limbs amputated will need to go through follow-up care, rehabilitation, and physical therapy to learn how to deal with this life-changing procedure.
Most patients start to notice the first positive changes and improvements in their strengths and mobility one to two years after surgery.
Cancer prevention is possible in some cases. For example, those who are looking to prevent lung cancer should quit smoking. Most adult cancers can be prevented with certain lifestyle changes, but this unfortunately isn’t the case for childhood cancers such as osteosarcoma.
Seeing how the known risk factors for osteosarcoma such as age, gender, and genetics can’t be changed, osteosarcoma can’t be prevented.
Prognosis and Survival Rate
The prognosis and survival rate for all cancers, including osteosarcoma, largely depends on how early it was caught and the stage of the disease when starting treatment.
If a patient is diagnosed with stage I osteosarcoma, their prognosis is excellent and they have a survival rate that is higher than 90%.
The prognosis for patients with stage II osteosarcoma varies greatly depending on the size and location of the tumor, as well as the length of the metastases. In the best-case scenario, the survival rate is approximately 50% after two years.
And finally, those treated for stage III osteosarcoma have an overall survival rate of approximately 30%.
Osteosarcoma Center at Sheba
Getting cancer can be a frightening experience for anyone, but especially for children and their parents. Even though it can be difficult to think about it, every parent should know what signs and symptoms to look out for and how to react if they suspect this or any other cancer.
We here at Sheba Medical Center have a team of professionals who have experience with treating both children and adults who suffer from osteosarcoma among many other diseases.
If you or one of your loved ones have been diagnosed with osteosarcoma or otherwise suspect you might have the disease, request a consultation. When you’re at Sheba, you’re in the best possible hands.
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