Every month, JBJS publishes a Specialty Update—a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Here is a summary of selected findings from studies cited in the December 17, 2014 Specialty Update on primary bone tumors:
Chondrosarcoma
–MicroRNA-145, an inhibitor of cell growth, was expressed at abnormally low levels in chondrosarcoma, lending credence to the hypothesis that underexpression of microRNA-145 plays a role in cancer development.
–Osteoclasts enhance the ability of chondrosarcoma to invade bone, but that invasion that can be partially halted by zoledronic acid.
–There is increased activity of the glycolysis-associated enzyme lactate dehydrogenase-A (LDHA) in chondrosarcoma.
–Density and location of new blood-vessel formation may be an important prognostic factor in chondrosarcoma.
–Conditional survival in patients with chondrosarcoma improves with each year of survival, but even patients who survive ten years after diagnosis cannot be considered cured.
Chordoma
–Variants of T transcription factor play a role in the pathophysiology of familial and sporadic chordoma.
–In patients with primary sarcomas of the spine, proton radiation plus surgery yielded local control rates of 85% at eight years.
Osteosarcoma
–Expression of the glucose transporter Glut-1 correlated with worse outcomes in patients with osteosarcoma.
–Secondary malignant neoplasms were found in 2.1% of long-term survivors of osteosarcoma.
–Use of fluorescence-guided surgery in a mouse model of osteosarcoma allowed reduction in the amount of residual tumor and improved disease-free survival.
–Among patients with high-grade osteosarcoma with soft-tissue extension, four parameters—tumor location, intracapsular extension, Huvos grade, and alkaline phosphatase level—may help predict which individuals will eventually develop metastases.
–In 45 patients with local recurrence but no metastases, the 10-year survival rate was 13%; most local recurrences were in soft tissue, not bone.
–Mid-therapy PET imaging may be useful to physicians in assessing response to chemotherapy.
Ewing Sarcoma
–Twenty-one percent of Ewing sarcoma samples had deletions of the STAG2 gene, and patients with STAG2 deletions had more aggressive tumors.
Soft-Tissue Sarcoma
–Among patients who also had surgery, intensity-modulated radiation therapy (IMRT) was associated with a lower local recurrence rate compared to conventional external-beam radiation.
–Six-month progression-free survival was 58% among 91 patients in a phase-II clinical trial of a hypoxia-activated cytotoxic agent (TH-302) used with doxorubicin.
–In a follow-up protocol comparison, radiography was noninferior to CT in terms of overall survival rate and disease-free survival.
–Ninety-five percent of 867 soft-tissue sarcoma patients who developed a recurrence did so within 8.6 years, raising questions about the usefulness of following patients beyond 10 years.
Reconstruction
–Due to high complication rates, intercalary allograft reconstruction after tumor resection should be reserved for defects of 15 cm or less, and plate-and-screw fixation should be used rather than intramedullary-nail fixation.
–Thirty-six patients who received frozen orthotopic autograft during reconstruction demonstrated a 10-year autograft survival rate of 80%.
–Patients who underwent pelvic reconstruction had a higher infection rate (26%), compared with those who did not undergo pelvic reconstruction (15%).