Osteosarcoma
Osteosarcoma: Excerpt from The 5-Minute Pediatric Consult
Susan R. Rheingold, MD
Osteosarcoma - BASICS
Osteosarcoma - description
A tumor of the bone composed of spindle cells that produce malignant osteoid
Osteosarcoma - epidemiology
- Osteosarcoma is the most common malignant bone tumor of childhood and adolescence, representing 60% of all bone tumors in the pediatric age group.
- Overall, it accounts for <1% of all malignant neoplasms.
- ~90% of tumors occur at the metaphyseal ends of long tubular bones, but any portion of the skeleton may be involved.
- The most frequent site is the distal femur, followed by the proximal tibia and the proximal humerus.
Osteosarcoma - incidence
- Peak incidence is in adolescence and early adulthood, with a median age of 18 at diagnosis.
- Thought to begin during the adolescent growth spurt
Osteosarcoma - risk factors
- Radiation exposure
- Paget disease of the bone
- Rothman-Thompson syndrome
- Enchondromatosis
- Hereditary multiple exostoses
- Fibrous dysplasia
- Hereditary retinoblastoma
Osteosarcoma - pathophysiology
- Osteosarcoma most often involves the medullary region of bone.
- Rarely, osteosarcoma occurs in soft tissue separate from underlying bone.
- Classic or conventional osteosarcoma, the largest group of osteosarcomas, is composed of connective tissue stroma containing highly malignant spindle-shaped cells as well as areas of osteoid production and calcification.
- 4 microscopic subtypes are osteoblastic, chondroblastic, fibroblastic, and telangiectatic. These variants are rare in the pediatric population and lack prognostic significance at present.
- 2 rare clinical subtypes, periosteal and parosteal osteosarcomas, rarely metastasize and carry a better prognosis.
Osteosarcoma - etiology
- The etiology of most cases is unknown.
- There is an association of osteosarcoma with exposure to ionizing radiation:
- Secondary osteosarcoma is seen in up to 5% of patients who received radiation therapy for an initial malignancy.
- Children with hereditary retinoblastoma are at increased risk of developing osteosarcoma with and without prior exposure to radiation.
Osteosarcoma - associated conditions
See “Risk Factors.”
Osteosarcoma - DIAGNOSIS
Osteosarcoma - signs & symptoms
- A tender, soft-tissue mass and increased warmth may be present in the involved area.
- Localized erythema is uncommon.
- Unless there exists an underlying fracture, range of motion of the limb is normal and there is no difficulty weight bearing.
- Regional lymphadenopathy is rare.
Osteosarcoma - history
- Pain at the site of the tumor is the most common presentation.
- Swelling over the involved area is also reported.
- The duration of symptoms varies.
- A history of recent trauma is common but unrelated. trauma often brings the affected area to the patient’s or parents’ attention, but does not actually cause osteosarcoma.
- Weight loss is rare, but may occur in advanced disease.
- If fever is present, it may indicate an infectious cause (osteomyelitis) rather than osteosarcoma.
Osteosarcoma - tests
Osteosarcoma - lab
- Laboratory tests are not generally helpful in osteosarcoma.
- Serum lactate dehydrogenase (LDH) and alkaline phosphatase may be elevated: The prognostic significance of alkaline phosphatase is controversial.
- An elevated WBC count, C-reactive protein, or sedimentation rate may suggest osteomyelitis.
Osteosarcoma - imaging
- A plain radiograph of the involved area always reveals some abnormality. Radiographic examination should include the primary tumor site as well as areas of potential metastases:
- Most commonly, one sees a lytic or blastic region of the bone with ill-defined borders.
- Other findings may include periosteal elevation adjacent to the primary lesion, a sunburst appearance of the primary lesion caused by neoplastic spicules adjacent to the bony cortex, or a pathologic fracture.
- A chest CT and bone scan should be done to assess for pulmonary and bone metastases.
- An MRI should be done to better evaluate the extent of the tumor:
- Include the joint above and below the involved bony area.
- MRI can delineate the intraosseous and extraosseous extent of the tumor as well as evaluate the neurovascular structures involved.
Osteosarcoma - diag proced-surgery
The diagnosis of osteosarcoma can be confirmed only by a biopsy, which should be done by an experienced pediatric orthopedic surgeon in conjunction with a pediatric oncologist and pediatric pathologist:
- Certain surgical incisions at the time of biopsy may make patients ineligible for limb-sparing procedures.
Osteosarcoma - differencial diagnosis
- Infection:
- Osteomyelitis
- Septic arthritis
- Trauma: Stress fracture
- Benign tumors:
- Unicameral bone cyst
- Osteoblastoma
- Eosinophilic granuloma
- Giant-cell tumor
- Aneurysmal bone cyst
- Osteochondroma
- Fibrous dysplasia
- Malignant tumors:
- Ewing sarcoma
- Chondrosarcoma
- Fibrosarcoma
- Leukemia
- Metastatic lesions of other primary tumors
Osteosarcoma - TREATMENT
Osteosarcoma - general measures
At present, therapy incorporates preoperative chemotherapy followed by surgical resection.
Osteosarcoma - special therapy
Osteosarcoma - radiotherapy
Osteosarcoma is a radiation-insensitive tumor, but radiation has been used in individual cases.
Osteosarcoma - phys therapy
- All patients need to work with specialists to learn how to adapt to their surgically induced disability.
- The duration of physical therapy and rehabilitation is dependent on the disability and the individual patient’s needs.
Osteosarcoma - medication
- The goals of adjuvant chemotherapy are treatment of pulmonary micrometastases and shrinkage of the primary tumor mass, particularly when limb-salvage procedures are surgical options. Response to adjuvant chemotherapy (degree of necrosis at the time of complete resection) is a very important prognostic factor.
- Groups such as the Children’s Oncology Group (COG) have developed chemotherapy protocols for osteosarcoma. Most children and adolescents with osteosarcoma are treated on these chemotherapy protocols. Many protocols are open to young adults up to the age of 30.
- The mainstays of treatment are cisplatin, high-dose methotrexate and doxorubicin, with many protocols adding ifosfamide and etoposide:
- The duration of chemotherapy varies from 8–12 months according to the extent of the tumor at diagnosis, tumor response to therapy, and the individual protocol.
Osteosarcoma - surgery
- In the past, when osteosarcoma was managed by surgery alone, most patients subsequently developed pulmonary metastases and died of progressive disease.
- Surgical options depend on the primary site of the tumor and the extent of tumor involvement.
- Complete surgical resection with wide margins is necessary for cure. Surgical options for osteosarcomas of the extremities include:
- Amputation
- Limb salvage with allograft or prosthetic reconstruction
- Rotationplasty
- Macroscopic pulmonary metastases should be resected at the time of surgery if still visible by radiographic examination:
- Localized pulmonary recurrences that develop after treatment also should be resected, as this can result in long-term cure or a prolonged symptom-free period.
Osteosarcoma - FOLLOW UP
Osteosarcoma - disposition
Osteosarcoma - issues for referral
When a malignant bone tumor is suspected, the patient should be referred immediately to a pediatric cancer center:
- Children’s cancer centers can provide the multidisciplinary team needed to diagnose, biopsy, treat, and rehabilitate children with bone tumors.
Osteosarcoma - prognosis
- Most patients with osteosarcoma involving an extremity without pulmonary metastases can be cured.
- 5-year survival for nonmetastatic disease ranges from 60–70%. The following have been associated with a poorer prognosis:
- Pulmonary metastases
- Disseminated bone metastases
- Poor response of the tumor to preoperative chemotherapy with tumor necrosis <95%
- Inability to achieve a total surgical excision of the tumor
Osteosarcoma - complications
- 10–20% of patients have pulmonary metastases at the time of diagnosis; a smaller proportion has metastases to other bones
- Wound infections may develop in surgical sites in the initial postoperative period. Significant pain, fever, swelling, discharge, and foul odor from the surgical site should be evaluated, preferably by the surgeon.
- Poor healing of the surgical site may be a problem, particularly in patients receiving chemotherapy or in those with poor nutrition. Patients may require IV antibiotics, supplemental feeding, and/or surgical revision of the wound.
Osteosarcoma - patient monitoring
- If prostheses are required, skin breakdown and fitting difficulties with prosthetic devices, such as adjustments for changes in height and weight, should be diagnosed and corrected. Scoliosis and back pain may develop in patients using improperly adjusted crutches and/or prosthetic devices after lower extremity or pelvic procedures. This requires expertise in prosthetic devices for children.
- Phantom pain is a normal phenomenon after amputation. Patients and their families should be reassured if this occurs. Sometimes medication can reduce the pain.
- All children need to be followed by an oncologist regularly after treatment is completed to monitor for recurrence as well as long-term side effects of the chemotherapy, such as cardiac toxicity, infertility, or secondary malignancy.
Osteosarcoma - bibliography
- Arndt CAS, Crist WM. Medical progress: Common musculoskeletal tumors of childhood and adolescence. N Engl J Med. 1999;341:342–352.
- Ferguson WS, Goorin AM. Current treatment of osteosarcoma. Cancer Invest. 2001;19:292–315.
- Grimer RJ. Surgical options for children with osteosarcoma. Lancet Oncol. 2005;6(2):85–92.
- Harting MT, Blakely ML. Management of osteosarcoma pulmonary metastases. Semin Pediatr Surg. 2006;15(1):25–29.
- Longhi A, Errani C, De Paolis M, et al. Primary bone osteosarcoma in the pediatric age: State of the art. Cancer Treat Rev. 2006;32(6):423–436.
- Miller SL, Hoffer FA. Malignant and benign bone lesions. Radiol Clin North Am. 2001;39:673–699.
- Rougraff BT, Simon MA, Kneisl JS, et al. Limb salvage compared with amputation for osteosarcoma of the distal end of the femur. A long-term oncologic, functional, and quality-of-life study. J Bone Joint Surg. 1994;76:649–656.
Osteosarcoma - CODES
Osteosarcoma - icd9
170.9 Osteosarcoma
Osteosarcoma - FAQ
- Q: How does one differentiate osteosarcoma from Ewing sarcoma, the second most common bone tumor of childhood?
- A: Ultimately, only a biopsy can differentiate the two. In general, Ewing sarcoma is seen in younger children and tends to affect the axial bones, such as the pelvis. When found in the long bones, it is usually in the diaphyseal regions. Symptomatology does not differ, but Ewing sarcoma can be metastatic to the bone marrow, as well as the bone and lung.
- Q: How does one differentiate osteosarcoma from a benign bone lesion?
- A: Ultimately, only a biopsy can differentiate the two. Benign lesions tend to be very well circumscribed with smooth edges on radiograph. They are generally not associated with soft tissue masses, swelling, or fever. Fractures are just as likely through benign bone lesions as malignant ones. Only in very rare situations should bony lesions be presumed to be benign and observed without biopsy.
- Q: Is there an increased risk of osteosarcoma in the contralateral limb?
- A: No.
- Q: Does limb salvage incur a greater risk of recurrence than does amputation?
- A: Recent studies have shown that there is no increase in recurrence if wide margins are achieved at the time of surgery.
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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