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Classification and external resources
Osteosarcoma - intermed mag.jpg
Intermediate-magnification micrograph of an osteosarcoma (center and right of image) adjacent to nonmalignant bone (left-bottom of image): The top-right of the image has poorly differentiated tumor. Osteoid with a high density of malignant cells is seen between the nonmalignant bone and poorly differentiated tumor (H&E stain).
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Classification and external resources
Osteosarcoma - intermed mag.jpg
Intermediate-magnification micrograph of an osteosarcoma (center and right of image) adjacent to nonmalignant bone (left-bottom of image): The top-right of the image has poorly differentiated tumor. Osteoid with a high density of malignant cells is seen between the nonmalignant bone and poorly differentiated tumor (H&E stain).
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Osteosarcoma is a cancerous bone tumor. Specifically, it is an aggressive malignant neoplasm--arising from primitive transformed cells of mesenchymal origin (and thus a sarcoma)--that exhibits osteoblastic differentiation and produces malignant osteoid.[1]

Osteosarcoma is the most common histological form of primary bone cancer.[2] It is most prevalent in children and young adults.[3]

Signs and symptoms[edit]

Many patients first complain of pain that may be worse at night, and may have been occurring for some time. Also, teenagers who are active in sports tend to complain about pain in their lower femur, or right below the knee. If the tumor is large, it can appear as a swelling. The affected bone is not as strong as normal bones and may fracture with minor trauma (a pathological fracture). According to Bone Cancer Research Trust, the pain may come and go and vary in intensity. The swelling will not be visible if it is not near the surface of the body such as on the pelvis.


The causes of osteosarcoma are not known. Several research groups are investigating cancer stem cells and their potential to cause tumors.[4] Radiotherapy for unrelated conditions may be a rare cause.[5]


Predilections of osteosarcoma

The tumor may be localized at the end of the long bone. Most often it affects the proximal end of tibia or humerus, or distal end of femur. Osteosarcoma tends to affect regions around the knee in 60% of cases, 15% around the hip, 10% at the shoulder, and 8% in the jaw. The tumor is solid, hard, irregular ("fir-tree," "moth-eaten", or "sun-burst" appearance on X-ray examination) due to the tumor spicules of calcified bone radiating in right angles. These right angles form what is known as Codman's triangle. Surrounding tissues are infiltrated.

High-magnification micrograph showing osteoid formation in an osteosarcoma, H&E stain

Microscopically: The characteristic feature of osteosarcoma is presence of osteoid (bone formation) within the tumor. Tumor cells are very pleomorphic (anaplastic), some are giant, numerous atypical mitoses. These cells produce osteoid describing irregular trabeculae (amorphous, eosinophilic/pink) with or without central calcification (hematoxylinophilic/blue, granular) - tumor bone. Tumor cells are included in the osteoid matrix. Depending on the features of the tumor cells present (whether they resemble bone cells, cartilage cells, or fibroblast cells), the tumor can be subclassified. Osteosarcomas may exhibit multinucleated osteoclast-like giant cells.[6]


Family physicians and orthopedists rarely see a malignant bone tumor (most bone tumors are benign). The route to osteosarcoma diagnosis usually begins with an X-ray, continues with a combination of scans (CT scan, PET scan, bone scan, MRI) and ends with a surgical biopsy. A characteristic often seen in an X-ray is Codman's triangle, which is basically a subperiosteal lesion formed when the periosteum is raised due to the tumor. Films are suggestive, but bone biopsy is the only definitive method to determine whether a tumor is malignant or benign.

The biopsy of suspected osteosarcoma should be performed by a qualified orthopedic oncologist. The American Cancer Society states: "Probably in no other cancer is it as important to perform this procedure properly. An improperly performed biopsy may make it difficult to save the affected limb from amputation." It may also metastasise to the lungs, mainly appearing on the chest X-ray as solitary or multiple round nodules most common at the lower regions.




Complete radical surgical en bloc resection is the treatment of choice in osteosarcoma.[2] Although about 90% of patients are able to have limb-salvage surgery, complications - particularly infection, prosthetic loosening and non-union - or local tumor recurrence may cause the need for further surgery or amputation. Mifamurtide is used after a patient has had surgery to remove the tumor and together with chemotherapy to kill remaining cancer cells to reduce the risk of cancer recurrence. Also, the option to have rotationplasty after the tumor is taken out exists.[8]

Patients with osteosarcoma are best managed by a medical oncologist and an orthopedic oncologist experienced in managing sarcomas. Current standard treatment is to use neoadjuvant chemotherapy (chemotherapy given before surgery) followed by surgical resection. The percentage of tumor cell necrosis (cell death) seen in the tumor after surgery gives an idea of the prognosis and also lets the oncologist know if the chemotherapy regimen should be altered after surgery.

Standard therapy is a combination of limb-salvage orthopedic surgery when possible (or amputation in some cases) and a combination of high-dose methotrexate with leucovorin rescue, intra-arterial cisplatin, adriamycin, ifosfamide with mesna, BCD (bleomycin, cyclophosphamide, dactinomycin), etoposide, and muramyl tripeptide. Rotationplasty may be used. Ifosfamide can be used as an adjuvant treatment if the necrosis rate is low.

Despite the success of chemotherapy for osteosarcoma, it has one of the lowest survival rates for pediatric cancer. The best reported 10-year survival rate is 92%; the protocol used is an aggressive intra-arterial regimen that individualizes therapy based on arteriographic response.[9] Three-year event-free survival ranges from 50% to 75%, and five-year survival ranges from 60% to 85+% in some studies. Overall, 65-70% patients treated five years ago will be alive today.[10] These survival rates are overall averages and vary greatly depending on the individual necrosis rate.

Fluids are given for hydration, while antiemetic drugs (such as the 5-HT3 receptor antagonists e.g. granisetron and ondansetron) help with nausea and vomiting. Filgrastim or pegfilgrastim help with white blood cell counts and neutrophil counts. Blood transfusions and epoetin alfa help with anemia.


Osteosarcoma is the eighth-most common form of childhood cancer, comprising 2.4% of all malignancies in pediatric patients, and about 20% of all primary bone cancers.[2]

Incidence rates for osteosarcoma in U.S. patients under 20 years of age are estimated at 5.0 per million per year in the general population, with a slight variation between individuals of black, Hispanic, and white ethnicities (6.8, 6.5, and 4.6 per million per year, respectively). It is slightly more common in males (5.4 per million per year) than in females (4.0 per million per year).[2]

It originates more frequently in the metaphyseal region of tubular long bones, with 42% occurring in the femur, 19% in the tibia, and 10% in the humerus. About 8% of all cases occur in the skull and jaw, and another 8% in the pelvis.[2]

Around 300 of the 900 people diagnosed in the United States will die each year. A second peak in incidence occurs in the elderly, usually associated with an underlying bone pathology such as Paget's disease of bone.


Prognosis is separated into three groups.

Deaths due to malignant neoplasms of the bones and joints account for an unknown number of childhood cancer deaths. Mortality rates due to osteosarcoma have been declining at about 1.3% per year. Long-term survival probabilities for osteosarcoma have improved dramatically during the late 20th century and approximated 68% in 2009.[2]

Research, information, and support[edit]

In the UK and Ireland, the Bone Cancer Research Trust funds research and provides information on osteosarcoma and other bone cancers, including information for teenagers who have this condition. In the US, the nonprofit organization Triumph Over Kid Cancer Foundation helps not only to raise awareness about osteosarcoma, but also helps raise funds to try to improve treatment and survivability of pediatric bone cancer. About 90% of their proceeds go to research and M.D. Anderson Cancer Hospital matches those funds dollar for dollar, and use all funds for research in pediatric sarcoma. The work will be done under the auspices of the Children's Sarcoma Initiative, and will feature a committee to solicit new research ideas in this area and fund those most likely to lead to progress. Also, because early diagnosis greatly improves prognosis, they work on educational efforts to increase awareness of bone cancer's signs and symptoms in parents and their pediatricians. Finally, since the life of pediatric bone cancer patients is so difficult, TOKC sets aside 10% of its proceeds to help fund the Sunshine Kids Organization, which works to bring some brief periods of happiness to the lives of these children.

Other animals[edit]

X-ray of osteosarcoma of the distal femur in a dog

Risk factors[edit]

Osteosarcoma is the most common bone tumor in dogs and typically afflicts middle-aged large and giant breed dogs such as Irish Wolfhounds, Greyhounds, German Shepherds, Rottweilers, mountain breeds (Great Pyrenees, St. Bernard, Leonberger, Newfoundland), Doberman Pinschers and Great Danes. It has a 10-fold greater incidence in dogs than humans.[13] A hereditary base has been shown in St. Bernard dogs.[14] Spayed/neutered dogs have twice the risk of intact ones to develop osteosarcoma.[15] Infestation with the parasite Spirocerca lupi can cause osteosarcoma of the esophagus.[16]

Clinical presentation[edit]

The most commonly affected bones are the proximal humerus, the distal radius, the distal femur, and the tibia,[17] following the basic premise "far from the elbow, close to the knee". Other sites include the ribs, the mandible, the spine, and the pelvis. Rarely, osteosarcoma may arise from soft tissues (extraskeletal osteosarcoma). Metastasis of tumors involving the limb bones is very common, usually to the lungs. The tumor causes a great deal of pain, and can even lead to fracture of the affected bone. As with human osteosarcoma, bone biopsy is the definitive method to reach a final diagnosis. Osteosarcoma should be differentiated from other bone tumours and a range of other lesions, such as osteomyelitis. Differential diagnosis of the osteosarcoma of the skull in particular includes, among others, chondrosarcoma and the multilobular tumour of bone.[18][19]

Treatment and prognosis[edit]

Amputation is the initial treatment, although this alone will not prevent metastasis. Chemotherapy combined with amputation improves the survival time, but most dogs still die within a year.[17] Surgical techniques designed to save the leg (limb-sparing procedures) do not improve the prognosis.

Some current studies indicate osteoclast inhibitors such as alendronate and pamidronate may have beneficial effects on the quality of life by reducing osteolysis, thus reducing the degree of pain, as well as the risk of pathological fractures.[20]


Osteosarcoma is also the most common bone tumor in cats, although not as frequently encountered, and most typically affects the rear legs. The cancer is less aggressive in cats than in dogs, so amputation alone can lead to a significant survival time.[17]


  1. ^ Luetke A, Meyers PA, Lewis A, Juergens H (2014). "Osteosarcoma treatment - where do we stand? A state of the art review." Cancer Treat Rev; 40 (4): 523-532. PMID 24345772
  2. ^ a b c d e f Ottaviani G., Jaffe N. (2009). The epidemiology of osteosarcoma. In: Jaffe N. et al. "Pediatric and Adolescent Osteosarcoma". New York: Springer. doi:10.1007/978-1-4419-0284-9_1. ISBN 978-1-4419-0283-2. PMID 20213383. 
  3. ^ "Osteosarcoma". US National Library of Medicine. PubMed Health. 2013. 
  4. ^ Osuna D, de Alava E (2009). "Molecular pathology of sarcomas". Rev Recent Clin Trials 4 (1): 12–26. doi:10.2174/157488709787047585. PMID 19149759. 
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  6. ^ Papalas JA, Balmer NN, Wallace C, Sangüeza OP (June 2009). "Ossifying dermatofibroma with osteoclast-like giant cells: report of a case and literature review". Am J Dermatopathol 31 (4): 379–83. doi:10.1097/DAD.0b013e3181966747. PMID 19461244. 
  7. ^ WHO
  8. ^ http://www.childrenscancer.org/main/kids_stories/lukes_story_surviving_osteosarcoma/
  9. ^ Wilkins RM, Cullen JW, Odom L, Jamroz BA, Cullen PM, Fink K, Peck SD, Stevens SL, Kelly CM, Camozzi AB: Superior survival in treatment of primary non-metastatic pediatric osteosarcoma of the extremity. Ann Surg Oncol 10:498-507, 2003.
  10. ^ Buecker, PJ, Gebhardt, M and Weber, K (2005). "Osteosarcoma". ESUN. Retrieved 2009-04-15. 
  11. ^ "osteosarcomasupport.org". osteosarcomasupport.org. Retrieved 2012-11-13. 
  12. ^ Koshkina, NV and Corey, S (2008). "Novel Targets to Treat Osteosarcoma Lung Metastases". ESUN. Retrieved 2009-04-14. 
  13. ^ Withrow, S.J. (2003). "Limb Sparing Trials and Canine Osteosarcoma". Genes, Dogs and Cancer: 3rd Annual Canine Cancer Conference, 2003. Retrieved 2006-06-16. 
  14. ^ Bech-Nielsen, S., Haskins, M. E. et al. (1978). "Frequency of osteosarcoma among first-degree relatives of St. Bernard dogs". J Natl Cancer Inst 60 (2): 349–53. PMID 271748. 
  15. ^ Ru, B., Terracini, G. et al. (1998). "Host related risk factors for canine osteosarcoma". Vet J 156 (1): 31–9. doi:10.1016/S1090-0233(98)80059-2. PMID 9691849. 
  16. ^ Ranen E, Lavy E et al. (2004). "Spirocercosis-associated esophageal sarcomas in dogs. A retrospective study of 17 cases (1997-2003)". Vet Parasitol 119 (2–3): 209. doi:10.1016/j.vetpar.2003.10.023. 
  17. ^ a b c Morrison, Wallace B. (1998). Cancer in Dogs and Cats (1st ed.). Williams and Wilkins. ISBN 0-683-06105-4. 
  18. ^ Loukopoulos P, Thornton JR , Robinson WF. Clinical and pathologic relevance of p53 index in canine osseous tumors. Veterinary Pathology 2003; 40:237-248
  19. ^ Psychas, V; Loukopoulos, P; Polizopoulou, ZS; Sofianidis, G (Mar 2009). "Multilobular tumour of the caudal cranium causing severe cerebral and cerebellar compression in a dog.". Journal of veterinary science 10 (1): 81–3. doi:10.4142/jvs.2009.10.1.81. PMC 2801101. PMID 19255529. Retrieved 13 November 2012. 
  20. ^ Tomlin, J. L., Sturgeon, C. et al. (2000). "Use of the bisphosphonate drug alendronate for palliative management of osteosarcoma in two dogs". Vet Rec. 

Further reading[edit]

External links[edit]