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9 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Desmoid tumours are locally aggressive growths of fibroblast-like cells, classed with soft-tissue sarcomas, driven by WNT mutations, that never spread to distant organs but can invade nerves, bowel and muscle. Many stop growing or shrink on their own, so watching first is standard; if they progress, the gamma-secretase inhibitor nirogacestat, approved in 2023, shrinks tumours and relieves pain.
Desmoid tumours are monoclonal fibroblastic proliferations driven by WNT pathway activation: about 85 percent carry somatic CTNNB1 (beta-catenin) mutations (T41A, S45F, S45P) and most of the rest arise in familial adenomatous polyposis through germline APC loss. They do not metastasise but infiltrate locally in the abdominal wall, mesentery, limbs and trunk, and their course is unpredictable: a substantial fraction stabilise or regress spontaneously, which is why the Desmoid Tumor Working Group consensus (2020) recommends active surveillance as the initial approach for most patients, with treatment reserved for progression or symptoms.
When treatment is needed the order has inverted over two decades: surgery, once first line, is now used selectively because recurrence after resection is common (S45F mutations and extra-abdominal sites recur most). Medical options are sorafenib (Alliance A091105, NEJM 2018: longer progression-free survival than placebo), nirogacestat (DeFi, NEJM 2023: fewer progressions than placebo with improvements in pain, symptom burden and physical function; FDA approval November 2023, the first drug approved for desmoid tumours), low-dose methotrexate-vinblastine or vinorelbine, and anthracycline chemotherapy for rapidly progressive disease. Cryoablation and high-intensity focused ultrasound offer local control for extra-abdominal tumours.
| Setting | Approach | Guideline |
|---|---|---|
| Newly diagnosed, asymptomatic or minimally symptomatic | Active surveillance with MRI at 1 to 2 months, then every 3 to 6 months; treat only on progression or symptoms. | NCCN Category 2A (observation) |
| Progressive or symptomatic disease | Nirogacestat (DeFi) or sorafenib (Alliance A091105); alternatives include methotrexate-vinblastine, vinorelbine, anthracycline-based chemotherapy for rapidly progressive disease, and cryoablation for accessible extra-abdominal tumours. | NCCN Category 1 (nirogacestat), Category 2A (sorafenib) |
| Surgery | Reserved for selected abdominal wall tumours or complications (bowel obstruction, fistula); margins do not reliably predict recurrence. | not mapped |