Desmoid: the role of local therapy in an era of systemic options.

OPINION STATEMENT: Extra-abdominal desmoid tumors continue to present unique challenges. Although the majority of patients can achieve durable local control, recalcitrant disease can prove frustrating for patients, their families, and providers. This is especially true when morbid local treatment modalities are undertaken in hopes of controlling a benign disease. There is little universal agreement regarding the optimal management of this potentially locally aggressive neoplasm; however, the overall goal of treatment is durable local control. Because of the unpredictable nature of desmoid tumors, treatment must be individualized on a case-by-case basis, utilizing a multimodal approach, and optimized in a multidisciplinary setting. Primary desmoid tumors that are symptomatic or progressing and can be excised with function-sparing surgery are treated operatively; surgical excision with negative margins (R0 resection) is generally the preferred method of treatment. Radiation therapy is used in combination with surgical resection for microscopically positive margins (R1 resection) when future recurrence may jeopardize limb preservation or function. For symptomatic or enlarging desmoids where surgery will incur significant functional deficits in order to obtain at best an R1 resection, definitive radiation or percutaneous ablation is utilized. Desmoid tumors that are asymptomatic, not enlarging, and located in areas that are remote from vital structures may be carefully observed. Systemic therapy is commonly utilized as an adjunct or primary treatment for symptomatic or enlarging tumors. The mainstay of treatment of recurrent desmoids tumor is surgery with a goal of an R0 resection often combined with radiation therapy. The evolving role of alternative methods of local control (such as cryoablation) is currently being investigated. As the cellular understanding of desmoid tumor improves, the ability to better predict the biological behavior will hopefully improve treatment selection.