Time trends in patients with aggressive fibromatosis Danique L.M. van Broekhoven¹, Dirk J. Grünhagen¹, Michael M.A. den Bakker², Thijs van Dalen³, Cornelis Verhoef¹   1. Department of Surgical Oncology, Erasmus MC, Rotterdam, the Netherlands. 2. Department of Pathology, Maasstad ziekenhuis Rotterdam, the Netherlands. 3. Department of Surgery, Diakonessenhuis, Utrecht, the Netherlands.

Incidence: 2 - 4 per milion people per year Current literature Incidence: 2 - 4 per milion people per year Source: Finnish studies in 1982-1987 Treatment: watchful waiting instead of surgery

Study Aim Evaluate time trends in incidence and treatment Method National pathology registry PALGA PALGA data: Conclusions and encoding of pathology reports Query: Extra-abdominal and abdominal wall desmoid tumors 1993-2013

Results 1134 patients Male : Female = 29% : 71% Median age = 37 years (IQR 30-50)

Age OR P Age (years) <20 0,992 0,635 20-44 0,977 0,027 45-64 1,017   OR P Continuous years Age (years) <20 0,992 0,635 20-44 0,977 0,027 45-64 1,017 0,173 65-79 1,035 0,069 80+ 1,052 0,296

Localization OR P Localization Head/Neck 0,981 0,342 Trunk 1,057   OR P Continuous years Localization Head/Neck 0,981 0,342 Trunk 1,057 <0,001 Abd. Wall 0,972 0,008 Extremity 0,124 Other 1,012 0,626

Diagnosis OR 1.096 (95%CI 1.072-1.121) P<0.001

Treatment OR 0.928 (95%CI 0.902-0.954) P<0.001

Time trends Rising incidence (2.5 fold)  Different diagnosis or better diagnostic tools?  True rise: Etiological factors? Rising incidence  Observed in all age groups, proportionally highest in older age  Particularly in trunk desmoids Work-up and treatment  Frequency pre-treatment biopsy >>  Non-surgical treatment >>

Time trends Rising incidence (2.5 fold)  Different diagnosis or better diagnostic tools?  True rise: Etiological factors? Rising incidence  Observed in all age groups, proportionally highest in older age  Particularly in trunk desmoids Work-up and treatment  Frequency pre-treatment biopsy >>  Non-surgical treatment >>

Time trends Rising incidence (2.5 fold)  Different diagnosis or better diagnostic tools?  True rise: Etiological factors? Rising incidence  Observed in all age groups, proportionally highest in older age  Particularly in trunk desmoids Work-up and treatment  Frequency pre-treatment biopsy >>  Non-surgical treatment >>

Time trends in patients with aggressive fibromatosis Danique L.M. van Broekhoven¹, Dirk J. Grünhagen¹, Michael M.A. den Bakker², Thijs van Dalen³, Cornelis Verhoef¹   1. Department of Surgical Oncology, Erasmus MC, Rotterdam, the Netherlands. 2. Department of Pathology, Maasstad ziekenhuis Rotterdam, the Netherlands. 3. Department of Surgery, Diakonessenhuis, Utrecht, the Netherlands.

Etiological factor: Surgery

Etiological factor: Hormones