Clinical Outcome of Tamoxifen and Sulindac for Desmoid Tumors in Adults: A Phase II Single Institution Experience

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 ≥۱۸ years of age who had measurable histologically confirmed recurrent or newly diagnosed tumors not amenable to R۰ resection, or those who underwent tumor excision with gross residual desmoid tumor. The primary objective was to estimate progression-free survival. Patients received ۲۰ mg tamoxifen and ۳۰۰ mg sulindac daily for up to ۱۲ months according to absence of disease progression or unacceptable drug toxicity. Results: ۲۵ patients, ۱۲ males and ۱۳ females, whose ages ranged from ۱۸-۶۰ years. Most (۸۸%) had a good performance status (ECOG ۱). A total of ۶ of ۱۵ patients with recurrent desmoid tumors had histories of prior local radiotherapy for their primary tumors. There were ۱۰ newly diagnosed patients, ۱۵ (۶۰%) had recurrent disease and only one patient had a diagnosis of familial adenomatous polyposis. Only ۲۲ 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 ۶۰%, with complete response observed in ۸% and partial response in ۵۲%. At two years, the estimated progression-free survival rate was ۵۵% with a median progressionfree survival of ۲۵ 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.