%0 Journal Article %A M Wedin %A K Stalberg %A J Marcickiewicz %A E Ahlner %A U Ottander %A Å Åkesson %A G Lindahl %A N Borendal Wodlin %A P Kjölhede %T 935 Body mass index as risk factor for lymphoedema one year after surgery for endometrial cancer. A prospective longitudinal multicentre study %D 2021 %R 10.1136/ijgc-2021-ESGO.213 %J International Journal of Gynecologic Cancer %P A131-A131 %V 31 %N Suppl 3 %X Introduction/Background*Risk factors for lymphoedema of the lower limbs (LLL) after treatment of endometrial cancer (EC) is disputed. Body mass index (BMI) is strongly associated with LLL. The aim of this study was to determine the impact of BMI on risk factors for LLL, assessed as crude volume increase ≥10% or as BMI-standardised volume increase (BMI-SV) ≥10%, one year after surgery for early-stage EC .Methodology An observational prospective multicentre study was conducted in 14 Swedish hospitals enrolling 234 women with EC; 116 underwent surgery including pelvic and para-aortic lymphadenectomy (LA) and 119 had surgery without LA. LLL was assessed at baseline preoperatively and one year postoperatively by systematic circumferential measurements of the legs, enabling estimation of leg volume. Leg volume was determined as the de facto volume, i.e. crude volume and as the leg volume to a standardised BMI, i.e. BMI-SV.Risk factors were analysed using multiple logistic forward stepwise regression models.Result(s)*Lower BMI and medication with diuretics were independent risk factors for LLL determined by crude leg volume ≥10% (aOR 0.88, 95%CI 0.80-0.97 and aOR 2.67, 95%CI 1.04-6.89, respectively) whereas LA was not a risk factor. The BMI and change in BMI from baseline to one year outweighed the effect of LA as a risk factor. Neither number of lymph nodes removed, location, nor extent of LA were independent risk factors for LLL determined by crude volume increase ≥10%.By using BMI-SV volume increase ≥10% as LLL independent risk factors were adjuvant radiation therapy (aOR 15.02, 95%CI 2.34–96.57), LA (aOR 14.42, 95%CI 3.49–59.62), diabetes mellitus (aOR 5.44, 95%CI 1.67–17.66), and age (aOR 1.07, 95%CI 1.00–1.15). Simultaneously, the number of lymph nodes removed, location and extent of LA were strongly predictive for development of LLL.Conclusion*BMI was a strong risk factor for LLL that outweighed the effect of obvious risk factors and therefore should be adjusted for when assessing LLL. Adjuvant radiation therapy and LA were strong independent risk factors for LLL together with age and diabetes mellitus. There is a need for a `gold standard` for determining LLL when addressing risk factors. %U https://ijgc.bmj.com/content/ijgc/31/Suppl_3/A131.1.full.pdf