Sorafenib for adults with desmoid tumors: experience from a Brazilian cancer center

Keywords

desmoid - desmoid tumor - sorafenib

Introduction: Desmoid Tumor (DT) is a rare neoplasm with uncertain behavior and no standard of care. Sorafenib (SOR), a tyrosine kinase inhibitor (TKI), has shown activity in DT and is indicated for patients (pts) who have progressive, symptomatic or refractory disease.

Methods: We conducted a retrospective, single-institution study to evaluate efficacy and safety of SOR in pts with confirmed DT treated in our center between January 2008 and May 2024. Clinicopathological features, outcomes and toxicities were collected from medical records. Efficacy was evaluated by tumor shrinkage according to RECIST criteria. Time-to-treatment discontinuation (TTD) was considered the interval from treatment initiation to discontinuation due to tumor progression, adverse events, physician and/or patients' choice, or death. Toxicity was evaluated according to CTCAE v5.0

Results: The study included 35 pts with a median age of 38 years (range: 13-69), of whom 71.4% were female. Six pts (17.1%) had Familial Adenomatous Polyposis. The most frequent tumor locations were the lower extremity (22.9%) and chest wall (22.9%). SOR was the 1st line of systemic therapy in 16 pts (45.7%), 2nd line in 11 (31.4%), and 3rd line in 8 (22.9%). With a median follow-up of 47 months (IQR: 16 - 68), the median TTD was 12 months (IQR: 29 - 12) and the median time to best response was 6 months (IQR: 17 - 2). Stable disease (SD) was observed in 48.6% of pts, partial response (PR) in 34.3% and 14.3% pts had disease progression. No pts achieved a complete response. Sixteen pts (45.7%) discontinued SOR due to maximum clinical benefit. Of these, ten pts (28.5%) experienced SD until the end of follow-up, with a median time of disease control after SOR discontinuation of 28.5 months (IQR: 10.5 - 31.25). Dose reduction was observed in 6 pts (17%) and 4 pts (11.4%) needed treatment interruption due to toxicities. Grade 3 skin rash, diarrhea, and palmar-plantar erythrodysesthesia syndrome occurred in 5.7% of the pts. No grade 4 or 5 toxicities were observed. At the end of the follow-up, 9 pts (25.7%) were still on SOR.

Conclusions: SOR exhibited clinical activity in this cohort of pts with DT, resulting in SD or PR in most cases. Notably, ten pts maintained a clinical response even after discontinuing the drug. The treatment was generally well-tolerated, with manageable side effects. Further research is needed to assess long-term efficacy and determine the optimal treatment duration.

Corresponding author: Pedro Henrique Benfatti Gomes (e-mail: [e-mail]).