Solitary Fibrous Tumour Outcomes: Unpredictable Biological Behaviors

1. Solitary fibrous tumoursThe outcomes of 106 patients illustrating the unpredictable biological behaviour N Alexander, K Thway, JM Thomas, A Hayes, DC Strauss Mr Dirk Strauss Consultant Surgeon

2. Introduction • Solitary fibrous tumours (SFT) are rare spindle cell tumour • May arise anywhere in body • Characteristic hypervasculartumours

3. Introduction • Solitary fibrous tumours (SFT) are rare spindle cell tumours • May arise anywhere in body • Characteristic hypervasculartumours VEGF over-expressed

4. Introduction • Solitary fibrous tumours (SFT) are rare spindle cell tumour • May arise anywhere in body • Characteristic hypervasculartumours VEGF over-expressed • Unpredictable behaviour “Benign SFT: Although no malignant features are seen, the behaviour of these tumours is unpredictable.”

5. Benign vs. Malignant SFT Benign or malignant Hypercellular Nuclear polymorphism Mitotic count > 4/10hpf Presence of necrosis

6. SFT are unpredictable Case A • 42 male • Vascular pelvic mass

7. SFT are unpredictable Case A • 42 male • Vascular pelvic mass Case B • 40 female • Vascular pelvic mass

8. SFT are unpredictable Case A • EUA and core needle biopsy • Solitary Fibrous Tumour (Benign) • Surgical resection • incomplete resection due to significant pelvic bleeding

9. SFT are unpredictable Case A • EUA and core needle biopsy • Solitary Fibrous Tumour (Benign) • Surgical resection • incomplete resection due to significant pelvic bleeding Case B • EUA and core needle biopsy x 2 • Solitary Fibrous Tumour (Benign) • Minimal clinical symptoms therefore opted to watch and wait

10. SFT are unpredictable Case A • 6 years following incomplete resection • continuing radiological observation of residual tumour -> stableand unchanged

11. SFT are unpredictable Case A • 6 years following incomplete resection • continuing radiological observation of residual tumour -> stable and unchanged Case B • 13 months from diagnosis presented with right arm pain and lytic lesion in humerus + lung metastases • died within 3 years of diagnosis

12. Aim • To review the clinical outcomes of patients managed with extra-pleural SFT

13. Method • Retrospective review 2000-2012 • Cases identified from histopathology database and prospective unit database • Classified as benign or malignant on basis of histopathology (surgery, biopsy) • Data collection included site, size, overall survival, local and systemic disease recurrence

14. Results - Demographics • 106 cases identified • 51 males, 55 female • median age = 60 years (range 18 - 88) • 58 benign vs. 48 malignant

15. Results - Demographics

16. Results - Site and Size

17. Results - Treatment • 91 patients underwent surgical resection • Followed up for median 45 months (range 3-144) • 2 patients died in perioperative period • 15 elected not to operate • 9 radiologic surveillance • 4 primary radiotherapy • 2 primary chemotherapy

18. Results - watch N = 9 patients: 8 abdomen/pelvis, 1 limb girdle • Benign SFT on biopsy • Serial cross sectional imaging Median follow up 28 months (11-60) • 1 death at 37 months metastasis • 5 stable disease 11 – 55 months • 3 marginal increase over 28, 37, 60 months

19. Results - Histopathology • 58 benign vs. 48 malignant • 91 patient had a biopsy + surgical resection • Final pathology diagnosis of resection specimen was different to core needle biopsy in 18 patients (20%)

22. Results - surgery

23. Results - surgery

24. Results - surgery

25. Results

26. Results

27. Primary radiotherapy N = 4 patients • 1 malignant SFT, 3 benign SFT Size • 2 stable (14, 49 months) • 2 regression (32, 43 months)

28. Primary radiotherapy March 2011 –> August 2013

29. Response Assessment in Radiotherapy Contrast enhanced ADC BOLD T2W 2 weeks following radiotherapy

30. Conclusion • Oncological behaviour of SFT is unpredictable

31. Conclusion • Oncological behaviour of SFT is unpredictable • Available pathologic markers of malignancy clearly correspond to a malignant behaviour with poor prognosis

32. Conclusion • Oncological behaviour of SFT is unpredictable • Available pathologic markers of malignancy clearly correspond to a malignant behaviour with poor prognosis • However: many pathological markers subjective: • cellularity, necrosis, pleomorphism • Risk model similar to GIST • (mitotic index/size/site/age/margins/??) • Benign v malignant: simplistic/confusing • low/intermediate/high risk SFT

33. Conclusion • Oncological behaviour of SFT is unpredictable • Available pathologic markers of malignancy clearly correspond to a malignant behaviour with poor prognosis • Core needle biopsy may not represent final diagnosis

34. Conclusion • Oncological behaviour of SFT is unpredictable • Available pathologic markers of malignancy clearly correspond to a malignant behaviour with poor prognosis • Core needle biopsy may not represent final diagnosis • Late relapses can occur in SFT

35. Conclusion • A cohort of difficult location tumours may be managed with observation

36. Conclusion • A cohort of difficult location tumours may be managed with observation • Radiotherapy: • vascular effect +/- multikinase anti-angiogenesis inhibitors • primary treatment/neoadjuvant treatment in tumours in difficult locations

37. Thank you