Background: Desmoid tumors are rare soft tissue neoplasms that have a variable and often unpredictable clinical course. We have conducted a phase II study to evaluate the efficacy and safety of tamoxifen and sulindac in treatment of primary unresectable and recurrent desmoid tumors.
Methods: Eligible patients were ≥18 years of age who had measurable histologically confirmed recurrent or newly diagnosed tumors not amenable to R0 resection, or those who underwent tumor excision with gross residual desmoid tumor. The primary objective was to estimate progression-free survival. Patients received 20 mg tamoxifen and 300 mg sulindac daily for up to 12 months according to absence of disease progression or unacceptable drug toxicity.
Results: 25 patients, 12 males and 13 females, whose ages ranged from 18-60 years. Most (88%) had a good performance status (ECOG 1). A total of 6 of 15 patients with recurrent desmoid tumors had histories of prior local radiotherapy for their primary tumors. There were 10 newly diagnosed patients, 15 (60%) had recurrent disease and only one patient had a diagnosis of familial adenomatous polyposis. Only 22 patients completed the treatment protocol and were evaluated for clinical response and time to progression. All patients were evaluated for safety profile. The overall response rate was 60%, with complete response observed in 8% and partial response in 52%. At two years, the estimated progression-free survival rate was 55% with a median progressionfree survival of 25 months.
Conclusion: According to the results of this study, systemic treatment with tamoxifen and nonsteroidal anti-inflammatory drugs is safe and effective in patients with desmoid tumors.