Clinicopathologic features of osteosarcoma in patients with Rothmund-Thomson syndrome.

PURPOSE: Patients with Rothmund-Thomson syndrome (RTS) and RECQL4 gene mutations have an increased risk of developing osteosarcoma (OS). Because RTS is considered a genomic instability syndrome, patients may experience increased toxicity with chemotherapy. The purpose of this study was to summarize the clinical features and response to therapy of OS in patients with RTS. The results of this analysis will help to define treatment guidelines for this complex and rare condition. PATIENTS AND METHODS: An international cohort of patients with RTS and OS was enrolled in an institutional review board-approved study at Baylor College of Medicine (Houston, TX). Medical records were reviewed, and the following information was extracted: clinical features, treatment, pathologic findings, and clinical outcome.
RESULTS: The median age at diagnosis of OS for the 12 patients was 10 years. The most common primary tumor sites were the long bones (femur, tibia); the most frequent histologic subtype was conventional OS. Histologic response to chemotherapy and outcome were similar to other published large series of sporadic OS. Eight patients are alive and disease free; four died as a result of cancer. Five patients required chemotherapy dose modifications, most commonly due to mucositis from doxorubicin.
CONCLUSION: Our results indicate that patients with RTS and OS are younger, but that their clinical behavior is similar to patients with sporadic OS. Our report suggests that these patients should initially be treated with conventional doses of chemotherapy as prescribed by current protocols; however, cautious and careful clinical observation is warranted to monitor for enhanced doxorubicin sensitivity in patients with RTS.