Surface osteosarcoma: Predictors of outcomes

J Surg Oncol. 2021 Sep;124(4):646-654. doi: 10.1002/jso.26531. Epub 2021 May 27.


Background and objectives: The subtypes of surface osteosarcomas include well-differentiated, low-grade parosteal osteosarcoma (POS), intermediate-grade periosteal osteosarcoma (PerOS), high-grade surface osteosarcoma (HGSO), and high-grade, dedifferentiated POS (dPOS). We aimed to determine disease progression, defined as local recurrence and metastatic disease, and overall (OS) and disease-specific survival (DSS). We identify outcome predictive factors and report functional results.

Methods: This retrospective study evaluated patients with primary surface osteosarcoma at our hospital from 1992 to 2019. Fifty-one patients had a median follow-up of 6.1 years (range: 0.1-25.2). Histologic subtypes included 32 POS, 11 PerOS, 4 HGSO, and 3 dPOS. Bone and soft tissue margins were classified using the American Joint Committee on Cancer residual tumor classification (Rx = Not evaluable; R0 = negative margin; R1 = microscopic positive margin; and R2 = macroscopic positive margin) and the modified R classification (mRx = not evaluable; mR0 = negative margin >1 mm; mR1 = negative margin ≤1 mm; mR1-dir: Positive microscopic margin locally; mR2a: Positive macroscopic margin locally; mR2b: positive macroscopic margin distally; and mR2C: positive macroscopic margin locally and distally). Forty-one patients had functional outcomes.

Results: Three POS patients developed recurrence: two had R0 margins and one an intralesional resection. Five patients developed lung metastases (POS: 3, dPOS: 2). Four patients died. The only significant disease progression predictor was age. OS at 10 years was 97%. 48 patients had negative bone margins (R0 or mR0 and mR1) and 47 patients had negative soft-tissue margins (R0 or mR0 and mR1). The average MSTS score was 88.43 (range: 34.29-100).

Conclusions: We advocate surgery for POS and believe R0 (mR0 and mR1 resections) or planned R1 (mR1-dir) to preserve function are acceptable. We favor chemotherapy and surgery for PerOS, though a chemotherapeutic response is highly variable. High-grade tumors are the most infrequent subtype, but HGSO and dPOS seem to portend a poorer prognosis. Good function can be obtained.

Keywords: clinical outcomes; surface osteosarcoma; surgical treatment; systemic treatment.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Bone Neoplasms / mortality*
  • Bone Neoplasms / secondary
  • Bone Neoplasms / surgery
  • Child
  • Female
  • Follow-Up Studies
  • Humans
  • Limb Salvage / mortality*
  • Lymphatic Metastasis
  • Male
  • Margins of Excision
  • Middle Aged
  • Neoplasm Recurrence, Local / mortality*
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / surgery
  • Osteosarcoma / mortality*
  • Osteosarcoma / pathology
  • Osteosarcoma / surgery
  • Prognosis
  • Retrospective Studies
  • Risk Factors
  • Survival Rate
  • Time Factors
  • Young Adult