Intercontinental collaborative experience with abdominal, retroperitoneal and pelvic schwannomas

Background

Schwannomas are rare tumours that pose a significant management challenge in the abdomen, retroperitoneum and pelvis. No data are available to inform management strategy.

Methods

A collaborative international cohort study, across specialist sarcoma units, was conducted to include adults presenting between 2000 and 2017 with histopathologically confirmed schwannomas within the abdomen, retroperitoneum or pelvis.

Results

Of 485 patients across 12 centres, 38 (7·8 per cent) were discharged without follow-up, 199 (41·0 per cent) underwent early resection and 248 (51·1 per cent) had radiological monitoring. Of these 248 patients, 96 (38·7 per cent) eventually had surgery, giving an overall resection rate of 60·8 per cent (295 of 485). At baseline, median tumour volume was 90·1 (i.q.r. 26·5–262·0) cm3. The estimated growth rate was 10·5 (95 per cent c.i. 9·4 to 11·6) per cent per year, and was consistent in the short term (within 2 years of diagnosis) and long term (beyond 2 years) (ρ = 0·405, P = 0·021). A decision to operate was more common in symptomatic patients (P < 0·001) and for rapidly growing tumours (growth rate more than 20 per cent per year) (P = 0·025). R0/R1 resection was achieved in 91·6 per cent of patients (263 of 287). Kaplan–Meier long-term recurrence rates after R0/R1 resection were 2·3 and 6·7 per cent at 3 and 5 years respectively.

Conclusion

Specific recommendations include: indications for early surgery, prediction of growth from radiological monitoring, promotion of selective submacroscopic resection and cessation of postoperative imaging surveillance.

Fenofibrate-induced nuclear translocation of FoxO3A triggers Bim-mediated apoptosis in glioblastoma cells in vitro

Anti-neoplastic potential of calorie restriction or ligand-induced activation of peroxisome proliferator activated receptors (PPARs) has been demonstrated in multiple studies; however, mechanism(s) by which tumor cells respond to these stimuli remain to be elucidated. One of the potent agonists of PPARα, fenofibrate, is a commonly used lipid-lowering drug with low systemic toxicity. Fenofibrate-induced PPARα transcriptional activity is expected to shift energy metabolism from glycolysis to fatty acid β-oxidation, which in the long-term, could target weak metabolic points of glycolysis-dependent glioblastoma cells. The results of this study demonstrate that 25 μM fenofibrate can effectively repress malignant growth of primary glial tumor cells and glioblastoma cell lines. This cytostatic action involves G(1) arrest accompanied by only a marginal level of apoptotic cell death. Although the cells treated with 25 μM fenofibrate remain arrested, the cells treated with 50 μM fenofibrate undergo massive apoptosis, which starts after 72 h of the treatment. This delayed apoptotic event was preceded by FoxO3A nuclear accumulation, FoxO3A phosphorylation on serine residue 413, its elevated transcriptional activity and expression of FoxO-dependent apoptotic protein, Bim. siRNA-mediated inhibition of FoxO3A attenuated fenofibrate-induced apoptosis, indicating a direct involvement of this transcription factor in the fenofibrate action against glioblastoma. These properties of fenofibrate, coupled with its low systemic toxicity, make it a good candidate in support of conventional therapies against glial tumors.