Can combined 18F-FDG-PET and dynamic contrast-enhanced MRI predict behavior of desmoid tumors in patients with familial adenomatous polyposis?

Volume-based 18F-FDG PET/CT predicts prognosis and outcome of active surveillance for intra-abdominal desmoid tumor

PURPOSE

Desmoid tumor (DT) is a rare monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Initial active surveillance is recommended by current guideline, and surgery is one of the main therapies for DT. Predicting the prognosis and outcome of active surveillance for intra-abdominal DT is pressing issue.

METHODS

The study included eighteen patients with intra-abdominal DT. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were measured. We analyzed their relationship with the outcome of active surveillance, as well as clinical, prognostic, and pathological data.

RESULTS

The MTV and TLG of recurrent DT were significantly higher than those of non-recurrent DT (P < 0.001 and P = 0.00, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing recurrent DT from non-recurrent DT were 760.8 for MTV (sensitivity = 1, specificity = 0.857 and AUC = 0.929), and 1318.4 for TLG (sensitivity = 1, specificity = 0.786, and AUC = 0.911). The cutoff values of MTV and TLG significantly correlated with PFS using the Kaplan-Meier method (P = 0.002 and P = 0.007, respectively). MTV and TLG could distinguish DTs with subsequent progression from stable ones (P = 0.004 and P = 0.004, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing DTs with subsequent progression from stable ones were 197.1 for MTV (sensitivity = 0.9, specificity = 1, and AUC = 0.900), and 445.45 for TLG (sensitivity = 0.9, specificity = 1, and AUC = 0.900).

CONCLUSION

Volume-based 18F-FDG-PET can predict prognosis of intra-abdominal DT. MTV and TLG can predict the outcome of active surveillance for intra-abdominal DT. MTV and TLG can potentially be predictors of surgical risk and difficulty.

Desmoid tumours in the surveillance era: What are the remaining indications for surgery?

The treatment of desmoid tumours (DTs) has greatly evolved in recent years, and surgery is no longer considered a first-line treatment. Percutaneous biopsy with molecular analysis for beta-catenin or APC gene mutation provides a certain diagnosis. After imaging, a specialized multidisciplinary tumour board (MDT) addresses the following therapeutic strategy. As more than half of patients stabilize or regress, despite initial progression, active surveillance is offered to most patients as the first option. Surgery is proposed for complications such as perforation and occlusion, which sometimes are the first manifestations of the disease. In these cases, limiting surgery to the treatment of complications and leaving the tumour in place is possible if significant bowel sacrifice is needed, especially in patients with previous colectomy for polyposis. Medical therapy is discussed by the MDT in cases of functional or life-threatening masses and is preferred to local treatments that could be mutilating and often incomplete. First-line surgery is now contraindicated in cases of incomplete unplanned surgery, recurrence, pregnancy or DTs occurring in familial adenomatous polyposis (FAP). The best indications of second-line surgery are significantly progressing disease when morbidity is acceptable, such as parietal locations. Medical and other locoregional treatments (radiotherapy, isolated limb perfusion and cryotherapy) should be considered by the MTB when surgery might cause sequelae.

[Desmoid tumors: Are there still any surgical indications?]

After an adapted imaging, the diagnosis of a desmoid tumor (DT) is provided by a percutaneous microbiopsy, with a molecular analysis for beta-catenin or APC gene mutation. The therapeutic strategy must be decided in a specialized multidisciplinary tumor board (MTB). Surgery is no longer the first-line treatment for a DT. Except within a surgical complication, active surveillance is offered to the majority of patients, since more than half stabilize or regress after an initial progression, whether the location is peripheral or intra-abdominal. If the localization and/or volume are likely to be functional or life-threatening, medical induction therapy is discussed in MTB, before a local treatment whose potential sequelae would be definitive. Incomplete unplanned resection, recurrence, pregnancy or desmoids occurring in a polyposis context are no longer routine surgical indications. In an emergency setting (occlusion, peritonitis), it is discussed to treat only the mechanical complication and leave the DT in place, if its resection would lead to too much digestive resection, especially in patients who have already undergone colectomy for polyposis. The best indications for surgery are patients who have parietal locations with significant and documented progression, because surgery can be easily completed at the cost of an acceptable morbidity. In localizations where surgery would cause sequelae, medical treatment or other regional loco treatments are discussed in MTB.

Management of genetically determined colorectal cancer

Surgeons are increasingly treating patients for colorectal cancer who are known to have a genetic predisposition to develop the disease; this may modify the surgical and oncological management of the patient. In this review the approach to the patient with colorectal cancer on a background of Lynch syndrome or familial adenomatous polyposis is explored.

Current Update on Desmoid Fibromatosis

OBJECTIVE

The purpose of this article is to review the etiopathogenesis, molecular cytogenetics, histopathology, clinical features, and multimodality imaging features of desmoid fibromatosis. Recent advances in the management of desmoid fibromatosis will also be discussed.

CONCLUSIONS

Desmoid fibromatosis is a rare soft tissue neoplasm with a high incidence of local recurrence. Imaging plays an important role in the diagnosis and management of this disease.