Osteosarcoma follow-up: chest X-ray or computed tomography?

In patients with relapsed osteosarcoma, the surgical excision of all metastases, defined as second complete remission (CR-2), is the factor that mainly influences post-relapse survival (PRS). Currently a validated follow-up policy for osteosarcoma is not available, both chest X-ray and computed tomography (CT) are suggested for lung surveillance. The purpose of this study is to evaluate whether the type of imaging technique used for chest surveillance, chest X-ray or CT, influenced the rate of CR-2 and prognosis in patients with recurrent osteosarcoma.

Patients up to 40 years with extremity osteosarcoma enrolled in consecutive clinical trials and treated at the Rizzoli Institute from 1986 to 2009 were identified. Only patients who had lung metastases alone as first pattern of recurrence were considered for the analysis. The rate of CR-2, overall survival (OS) and PRS were the end-points of the study.

The median follow-up was 47 months (1-300), 215 patients were eligible. Lung metastases were detected by chest X-ray in 100 (47%) patients, by CT in 112 (52%) and by symptoms in 3 (1%). CR-2 rate was 60% for patients followed by X-rays and 88% for those followed by CT (p < .0001). 5-year PRS was 30% (95% CI 21-39) in the X-ray group and 49% (95% CI 39-59) in the CT group (p = .0004). 5-year OS was 35% (95% CI 26-44) in the X-ray group and 60% (95% CI 51-70) in the CT group (p = .004).

A follow-up strategy with chest CT leads to a higher rate of CR-2 and significantly improves PRS and OS in osteosarcoma, compared to chest X-ray.