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Bone sarcomas — osteosarcoma, Ewing sarcoma and chondrosarcoma

Osteosarcoma and Ewing sarcoma are treated with chemotherapy before and after local therapy (surgery, and in Ewing also radiation), whereas chondrosarcoma resists chemotherapy and radiation and is treated by surgery; the biopsy is done at a sarcoma centre along the planned incision tract.

לקריאה בעברית

Why it matters in the exam

Bone sarcomas appear in the exam in questions on treating a single lung metastasis after osteosarcoma, osteosarcoma in an older adult, localised Ewing sarcoma, and fertility preservation before chemotherapy with alkylating drugs. The candidate must distinguish the three types by age, location and imaging appearance.

Recurring points: lung metastases in osteosarcoma are resected surgically and can be cured; Ewing sarcoma is radiosensitive so radiation is an alternative or addition to surgery; and in older patients high-dose methotrexate is hard to give. The clinical story matters too: night pain and swelling around the knee in an adolescent, or fever and weight loss with a pelvic mass in a young adult.

Key points

Osteosarcoma occurs mainly in adolescents and older adults, around the knee, and is treated with MAP chemotherapy, limb-sparing surgery and further chemotherapy.
Necrosis of 90% or more in the resected tumour marks a good response, and lung metastases are resected and can be cured.
Ewing sarcoma arises from t(11;22), occurs in the diaphysis and pelvis and is treated with VDC and IE plus surgery or radiation.
Chondrosarcoma occurs mainly in adults, resists chemotherapy and conventional radiation, and so is treated by surgery with wide margins.
The biopsy is done only at a sarcoma centre and along the planned incision tract, so it is removed at surgery, and fertility preservation is arranged before alkylating drugs.

Summary table

Type	Features	Treatment
Osteosarcoma	Adolescents and older age (Paget disease, prior radiation); metaphysis of distal femur and proximal tibia; "sunburst" and Codman triangle	MAP chemotherapy (high-dose methotrexate, doxorubicin, cisplatin), limb-sparing surgery, and further chemotherapy
Pathological response in osteosarcoma	Necrosis of 90% or more in the resected tumour — good response	Predicts prognosis; the role of radiation is limited to unresectable sites
Lung metastases in osteosarcoma	Surgical resection of the metastases	Can lead to cure, even in late relapse
Osteosarcoma in an older adult	Surgery, and chemotherapy adjusted to tolerance	High-dose methotrexate is hard to tolerate in older age
Ewing sarcoma	Children and young adults; diaphysis and pelvis; t(11;22) with EWSR1-FLI1; "onion skin"; fever and weight loss	Alternating VDC and IE chemotherapy, and local therapy with surgery, radiation or both
Chondrosarcoma	Adults; pelvis and long bones; IDH1 and IDH2 mutations	Surgery with wide margins; resistant to chemotherapy and conventional radiation
General principles	Biopsy at a sarcoma centre along the planned incision tract	Fertility preservation before alkylating drugs (cyclophosphamide, ifosfamide)

In the full version for subscribers

A simple algorithm
Memory aid
Exam traps
5 review cards
Enough for IMLE

The full version is open to subscribers of: Oncology, Orthopedic surgery, Pediatrics.

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Sources

ESMO-EURACAN-GENTURIS-ERN PaedCan Clinical Practice Guideline: Bone sarcomas, 2021 — Diagnosis, treatment and follow-up
NCCN Clinical Practice Guidelines in Oncology: Bone Cancer, 2026 — Osteosarcoma, Ewing sarcoma and chondrosarcoma
DeVita, Hellman and Rosenberg's Cancer: Principles and Practice of Oncology, 12th ed. (2023) — Sarcomas of bone

Sources are given for further reading; the text is written afresh and not copied from them.

Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.