Treatment of Aggressive Pelvic Fibromatosis With Interferon

[Biology and signaling pathways involved in the oncogenesis of desmoid tumors]

Desmoid tumors (TDs) are derived from mesenchymal stem cells and their pathogenesis is strongly linked to the Wingless/Wnt cascade where the deregulation of β-catenin plays a major role. A mutation of the CTNNB1 encoding β-catenin is found in the majority of sporadic TD cases and constitutional mutations of APC have been described in heritable forms in patients with familial adenomatous polyposis (FAP). Estrogens could also play a role in pathogenesis and this is the basis for the use of hormone therapy. Other signaling pathways have been involved in the development of TDs such as Notch, Hedgehog, JAK/STAT, PI3 Kinase/AKT and mTOR. Metalloproteases are expressed in TDs and play a role in invasiveness. TGF-ß, as a growth factor, stimulates the transcriptional activity of β-catenin. Future studies will need to focus on better describing and understanding the immune environment of TDs. One of the major difficulties for the experimental study of TDs is the virtual absence of a preclinical model, either in vitro or in vivo. This is partly why the interactions between the different signaling pathways presented here and their consequences for the development of TDs are still poorly understood.

Activated Signaling Pathways and Targeted Therapies in Desmoid-Type Fibromatosis: A Literature Review

Desmoid-type fibromatosis (DTF) is a rare, soft tissue tumor of mesenchymal origin which is characterized by local infiltrative growth behavior. Besides “wait and see,” surgery and radiotherapy, several systemic treatments are available for symptomatic patients. Recently, targeted therapies are being explored in DTF. Unfortunately, effective treatment is still hampered by the limited knowledge of the molecular mechanisms that prompt DTF tumorigenesis. Many studies focus on Wnt/β-catenin signaling, since the vast majority of DTF tumors harbor a mutation in the CTNNB1 gene or the APC gene. The established role of the Wnt/β-catenin pathway in DTF forms an attractive therapeutic target, however, drugs targeting this pathway are still in an experimental stage and not yet available in the clinic. Only few studies address other signaling pathways which can drive uncontrolled growth in DTF such as: JAK/STAT, Notch, PI3 kinase/AKT, mTOR, Hedgehog, and the estrogen growth regulatory pathways. Evidence for involvement of these pathways in DTF tumorigenesis is limited and predominantly based on the expression levels of key pathway genes, or on observed clinical responses after targeted treatment. No clear driver role for these pathways in DTF has been identified, and a rationale for clinical studies is often lacking. In this review, we highlight common signaling pathways active in DTF and provide an up-to-date overview of their therapeutic potential.

Medical treatment of mammary desmoid-type fibromatosis: which benefit?

Background

Breast fibromatosis is a rare disease characterized by monoclonal fibroblast proliferation. It has no ability to metastasize but has a high local recurrence rate and often infiltrates surrounding tissues. Surgical treatment is the reference, but recently, new targeted therapies have emerged. We report an original case of a patient with breast fibromatosis who received exclusive medical treatment. Our aim was to analyze these treatments based on the clinical and radiological outcome, iatrogenic effects, and pharmacological action.

Case presentation

We report the case of a 19-year-old woman who developed a desmoid-type fibromatosis of the lower inner quadrant of the right breast, measuring 50 × 25 mm (i.e., a volume of 27.4 cm³). Initial surgery was not possible because of potential esthetic and functional prejudice. Thus, she had an exclusive medical treatment including several lines: NSAIDs with tamoxifen and triptorelin, followed by sorafenib, then interferon α2b, and finally sunitinib. With tyrosine-kinase inhibitors (TKIs) (sunitinib), a significant partial response was observed (57% reduction of the maximal tumoral volume). For each treatment, we provided the clinical and radiological outcome in association with known pharmacological action.

Conclusions

TKI had been an interesting alternative option to initial surgery, providing at least a partial response and potentially allowing less mutilating surgery. However, no pharmacological mechanism can unequivocally explain TKI efficacy. In general, breast fibromatosis should be treated along with oncologist and interventional radiologists in a trans-disciplinary modality, thus offering an adapted treatment for this particular desmoid-type fibromatosis localization.