In desmoid tumor, initial management often relies on active surveillance. When surveillance can no longer achieve its intended purpose — controlling tumor size and preventing growth — escalation to systemic medical therapy is indicated.
Active surveillance with regular clinical and imaging follow-up has not met its goals: stable tumor size on imaging and absence of tumor growth at multiple consecutive follow-up appointments. This documented progression is the trigger that escalates care to active medical treatment.
The next treatment line introduces systemic medical therapy. Multiple agents are available, spanning different drug classes, with varying levels of supporting evidence and differing safety profiles. The general approach favours initiating treatment with the option carrying the most desirable safety profile, with stepwise escalation to agents of greater potential toxicity as needed.
Full agent selection, recommended sequencing, and all dosing details are in the complete protocol below.
Absence of disease progression on imaging at 6 months; tumor size stability or reduction. A treatment course of at least 6 months is generally required before effectiveness can be assessed.
The consensus of the Desmoid Tumor Working Group was that for most of the available treatments, a course of at least 6 months is required (provided there is absence of frank progression) prior to assessing effectiveness.
In general and excluding issues of drug availability and cost, which may vary considerably, it is reasonable to use the treatment with more desirable safety profile initially, followed by agents with potentially more toxic effects in a stepwise fashion.