Recent Advances and Current Management for Desmoid Tumor Associated with Familial Adenomatous Polyposis

For nearly half a century, desmoid tumor (DT) has been considered a major complication that occurs in approximately 10%-25% of familial adenomatous polyposis (FAP) patients. It is also the leading cause of death in patients undergoing colectomy. We believe that the mortality rate is improving due to the understanding of the natural history of DT and recent advances in medical treatment. The risk factors of DT development include trauma, having a distal germline APC variant, having a family history of DTs, and estrogens. In the era of minimally invasive surgery, several reports demonstrated no significant difference in both surgical approach (laparoscopic vs. open) and surgical procedure (ileal pouch-anal anastomosis vs. ileorectal anastomosis). Regarding the treatment of FAP-associated DT, rapidly proliferating and life-threatening intra-abdominal DT accounts for approximately 10% of FAP-associated DT; however, it has been shown that it can be controlled by identifying and introducing cytotoxic chemotherapy. Moreover, tyrosine kinase inhibitors and γ-secretases, which are used to treat sporadic DT, which is more frequent than FAP-associated DT, are expected to be effective. In the future, such treatment is expected to further reduce the mortality rate from DT associated with FAP. In addition to the conventional staging of intra-abdominal DT, the classification proposed in Japan was recently thought to be useful for the treatment strategy of FAP-associated DTs. In this review, we summarize the recent advances and current management for the FAP-associated DT, including recent data from Japan.