Developing an Evidence-based Followup Schedule for Bone Sarcomas Based on Local Recurrence and Metastatic Progression

Area of Science:

• Oncology
• Sarcoma Research
• Clinical Surveillance

Background:

• Primary bone sarcomas require diligent follow-up due to risks of local recurrence and pulmonary metastasis.
• Current surveillance protocols lack evidence-based guidelines for optimal timing and frequency.

Purpose of the Study:

• To determine the frequency and timing of local recurrence and metastasis in bone sarcomas by histologic grade.
• To propose evidence-based modifications to current surveillance schedules to improve detection of pulmonary metastatic events.

Main Methods:

• Retrospective review of 665 patients with primary, nonmetastatic bone sarcoma (1989-2010).
• Kaplan-Meier survival analysis and Cox regression to evaluate recurrence and metastasis rates.
• Calculation of new pulmonary metastatic events per patient-year to inform surveillance frequency.

Main Results:

• Local recurrence-free survival did not differ significantly by sarcoma grade.
• Metastasis-free survival varied significantly by grade (p < 0.001).
• Grade 1 sarcomas showed no metastases after 3 years; Grades 2 and 3 continued to metastasize up to 10 years.

Conclusions:

• Pulmonary screening beyond 5 years is likely unnecessary for Grade 1 bone sarcomas.
• Continued surveillance until 10 years is recommended for Grade 2 and 3 bone sarcomas.
• Proposed surveillance schedules aim to increase the detection rate of pulmonary metastases per examination.