What Are the Differences Between Osteosarcoma and Sarcoma?

Medically Reviewed on 1/17/2023
Differences Between Osteosarcoma and Sarcoma
Treatment options for osteosarcoma and sarcoma include chemotherapy, surgery, and radiotherapy.

Osteosarcoma begins in the bones, whereas sarcoma can originate in any part of the body.

Osteosarcoma, also known as osteogenic sarcoma, is the most prevalent cancer that begins in the bone-forming cells. Osteosarcoma is most commonly found in the long bones, more prevalently the legs but occasionally the arms, but it can begin in any bone. In very rare cases, it can occur in soft tissue outside the bone.

A sarcoma, on the other hand, is a form of cancer that can develop in many parts of your body. Sarcoma is a broad term for a group of tumors that start in the bones and soft tissues (soft tissue sarcoma).

What are the survival rates of osteosarcoma and sarcoma?

Osteosarcoma survival rate

  • For people with osteosarcoma, the overall five-year survival rate is 60 percent.
  • If cancer is discovered at a localized stage, the five-year survival rate is 74 percent.
  • If cancer has progressed to the local lymph nodes, surrounding tissues, or organs, the five-year survival rate is 66 percent.

Sarcoma survival rate

  • Sarcoma has an overall five-year survival rate of 65 percent.
  • Localized sarcomas account for about 60 percent of all cases of sarcoma.
  • The five-year survival rate for people with localized sarcoma is 81 percent.
  • Locally progressed sarcomas are seen in about 18 percent of cases.

What are the stages of osteosarcoma?

Professionals can choose the best course of therapy and the most probable outcome by staging and classifying a bone tumor.

Under a microscope, tumor cells are examined to determine how they differ from healthy bone tissue before being evaluated.

A grade I tumor has cells that resemble bone tissue, whereas a grade III tumor has more abnormal cells that point to a more aggressive cancer.

Staging reveals the size and spread of a tumor. Because each stage can have several different qualities, except for stage III, each stage contains two substages. 

Four stages of osteosarcoma

  1. Stage I: The tumor is 8 cm and has not spread from its original location. It can be a low-grade tumor or the grade cannot be ascertained through tests. It is the most curable stage of bone cancer.
  2. Stage II: This cancer is of a higher grade and can be the same size as a stage I tumor in some cases. It is more aggressive compared with stage I tumors.
  3. Stage III: Tumors have formed in at least two locations within the same bone but have not yet migrated to the lungs or lymph nodes. A bone tumor in stage III would have a high grade.
  4. Stage IV: This is the most advanced stage of bone cancer. A tumor in stage IV will have appeared in more than one area and migrated to the lungs, lymph nodes, or other organs.

The cancer stage determines the type of treatment and the outcome.

What are the stages of sarcoma?

Staging systems give medical professionals consistent language to describe cancers. Following a soft tissue sarcoma diagnosis, several tests are performed to determine cancer's extent and whether it has spread from the original site to other body parts.

Cancer's size, aggressiveness, and growth are described by staging, establishing the course of treatment. 

Soft tissue sarcoma staging aims to discover the following:

  • The size of the tumor
  • Whether the malignancy has spread to nearby lymph nodes and tissues
  • Whether cancer has spread to other regions of the body

Staging soft tissue sarcomas

The stage of the cancer is determined by diagnostic testing; therefore, staging might not be finalized until all the tests have been finished.

Identifying the stage assists the doctor in selecting the most appropriate action and can help determine the prognosis of a person with soft tissue sarcoma.

The staging of soft tissue sarcomas can be done using the TNM staging system, where:

  • T stands for features of the tumor (size and location)
  • N stands for the lymph node spread
  • M stands for metastasis (tumor spreading to a different part of the body than where it started)

T stages

  • T1: Tumor is 5 cm (about two inches) or less in size.
  • T1a: The tumor is close to the skin surface.
  • T1b: The tumor is deep.
  • T2: Tumor is more significant than 5 cm.
  • T2a: The tumor is close to the skin's surface.
  • T2b: The tumor is deep.

N stages

  • N0: Cancer has not spread to the lymph nodes near the tumor.
  • N1: Cancer has spread to the lymph nodes nearby.

M stages

  • M0: Cancer has not progressed beyond the bone or surrounding lymph nodes.
  • M1: Distant metastasis (cancer has spread to other body parts).
  • M1a: Cancer has only reached the lung.
  • M1b: Cancer has spread to more sites, such as the brain and liver.

TNM stage grouping

After ascertaining the T, N, and M stages and grades of the soft tissue sarcomas, the data is combined and expressed as an overall stage. The process of allocating a stage number is called stage grouping.

Soft tissue sarcomas can be divided into the following stages:

  1. Stage IA
    • T1, N0, M0, G1, or GX: The tumor does not exceed 5 cm (two inches) in diameter (T1). It has not spread to lymph nodes (N0) or other locations (M0). Grade I cancer is present (or the grade cannot be assessed).
  2. Stage IB
    • T2, N0, M0, G1, or GX: The tumor measures more than two inches (5 cm) across (T2). No lymph nodes (N0) or other distant sites have been affected by it (M0). Grade I cancer is present (or the grade cannot be assessed).
  3. Stage IIA
    • T1, N0, M0, G2, or G3: The tumor does not exceed 5 cm (two inches) in diameter (T1). No lymph nodes (N0) or other distant sites have been affected by it (M0). The cancer is stage II or III.
  4. Stage IIB
    • T2, N0, M0, G2: The tumor measures more than 5 cm (two inches) in diameter (T2). No lymph nodes (N0) or other distant sites have been affected by it (M0). Grade II cancer is present.
  5. Stage III
    • T2, N0, M0, and G3: It measures more than 5 cm (two inches) in length (T2). No lymph nodes (N0) or other distant sites have been affected by it (M0). Grade III cancer is present.
    • Any T, N1, M0, and any G: Cancer may be of any size and any grade. Nearby lymph nodes have been affected by it (N1). It has not spread to other locations (M0).
  6. Stage IV
    • Any G, Any T, any N, or M1: Cancer has spread to nearby (N1) or distant areas (M1). It might be any size (T) or grade (any G).


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What are the treatment options for osteosarcoma and sarcoma?

The most often-used treatment options for osteosarcoma include chemotherapy, surgery, and radiotherapy. 

For sarcoma, frequently used treatment options are chemotherapy, surgery, radiotherapy, targeted therapy, immunotherapy, and ablation therapy.

Osteosarcoma treatment options

  • Surgery
    • The purpose of surgery is to remove all cancer cells. However, arranging the operation considers how it will affect your capacity to go about your regular life. The scope of surgery for osteosarcoma is determined by a variety of factors, including the tumor's size and location.
    • The following procedures are used to treat osteosarcoma:
      • Limb-sparing surgery (removes only cancer cells) 
      • Amputation (surgery to remove the affected limb)
      • Rotationplasty (surgery to remove the lower portion of the leg)
  • Chemotherapy
    • Chemotherapy uses medication to kill cancerous cells. Chemotherapy treatments often comprise two or more medications that can be administered orally, intravenously or both ways.
    • Chemotherapy is frequently advised before surgery for osteosarcoma (neoadjuvant therapy). Doctors examine how cancer cells respond to chemotherapy to plan future treatments.
    • If the osteosarcoma reduces after the treatment, limb-saving surgery may be possible.
    • If the osteosarcoma does not respond to treatment, cancer may become very aggressive. Doctors may recommend a different combination of chemotherapy treatments or a more aggressive procedure to ensure that all of cancer has been removed. Chemotherapy may be used after surgery to eliminate any remaining cancer cells. If osteosarcoma returns after surgery or spreads to other parts of the body, chemotherapy may be prescribed to slow the progression of the disease. 
  • Radiation therapy
    • High-energy beams, including X-rays and protons, are used in radiation therapy to kill cancer cells. Radiation may be an option in some situations, such as when surgery is not an option or surgeons cannot completely remove cancer.
    • Energy beams are projected from a machine that moves around you as you lie on a table during radiation therapy. To minimize the possibility of damaging the surrounding healthy cells, the beams are precisely focused on the osteosarcoma.

Treatment of sarcoma

Surgery is often used to treat sarcoma and remove cancer. Before or after surgery, other treatments may be used. The best treatment option varies from person to person, depending on the following:

  • The type of sarcoma
  • The location of the tumor 
  • How aggressive are the cells are
  • Whether cancer has spread to other parts of your body

Sarcoma treatment options include:

  • Surgery 
  • Chemotherapy
  • Radiation therapy

Other treatment options for sarcoma include:

  • Targeted therapy: A type of medication that targets abnormalities in cancer cells. Your doctor may examine your sarcoma cells to determine whether they are likely to respond to medications used in targeted therapy.
  • Immunotherapy: A medication treatment that uses your immune system to fight cancer. Because cancer cells generate proteins that make immune system cells blind, your body's immune system may fail to combat your cancer—Immunotherapy medicines act by disrupting this process.
  • Ablation therapy: Destroys cancer cells by heating them with electricity, freezing them with very cold liquid, or damaging cells with high-frequency ultrasound waves.
Medically Reviewed on 1/17/2023
Image Source: iStock image

What Is Osteosarcoma? https://www.cancer.org/cancer/osteosarcoma/about/what-is-osteosarcoma.html

Osteosarcoma (Osteogenic sarcoma) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1794406/

Osteosarcoma https://www.mayoclinic.org/diseases-conditions/osteosarcoma/symptoms-causes/syc-20351052

Osteogenic Sarcoma https://www.hopkinsmedicine.org/kimmel_cancer_center/cancers_we_treat/pediatric_oncology/becoming_our_patient/cancer_types/osteogenic_sarcoma.html

Sarcoma https://my.clevelandclinic.org/health/diseases/17934-sarcoma