Decision-Making In The Older Patient With Diagnosis Of Cancer: Sarcopenia And Frailty As Predictors Of Toxicity To Chemotherapy-Oncosarco Project.

e21525 Background: Given the high risk of toxicity to chemotherapy (CT) in elderly, decision making in this population is complex. In this sense, the project ONCOSARCO aims: 1) To know what (frailty [F] or sarcopenia) is the best predictor of toxicity to CT; 2) To identify new predictors of toxicity (To) between variables related to muscle mass (MM), muscle strength (MS) or physical function (PF). Methods: Between 12/2012 and 12/2014, 103 patients (≥ 70 years) were included. MM (muscle mass index), MS (handgrip, spherical strength, pinch-gauge, knee-extension strength, hip-flexion strength) and PF (gait speed and 5-to sit chair test) were recorded before starting CT. European Working Group on Sarcopenia in Older People (EWGSOP)’s criteria were used to define sarcopenia and Linda Fried’s criteria were used to detect frailty. Toxicities of grade 3-4 were used as final event, and mortality without severe To was used as a competitive event. It was used a multinomial logistic regression analysis to predictors of severe To. Results: Severe toxicity appeared in 44 patients (42.7%); 30 patients had no To (29.1%); 29 patients died without toxicity of CT (28.2%).Frail patients had no a higher risk of making To (p = 0.220) than prefrail patients. After adjusting by full doses of CT and tumoral stage, F was associated with more severe toxicity from CT, but not significantly (RR = 2.4; 95% CI 0.9 to 6.9; p = 0.090). Sarcopenia was not good predictor of To to CT in older patients with cancer (p = 0.59).It was built a predictive model of To by using variables related to MM, MS and PF. In the analysis, the only variable that was significantly associated with To was the strength of knee extension (RRR 0.7, 95% CI: 0.5-0.9; p = 0.031).1 Conclusions: In the field of Oncogeriatry, frail patients showed 2.4 times higher risk of developing To to CT (p = 0.090) than prefrail patients. Sarcopenia was not associated with To, unlike the force of knee extension (p = 0.031). Further studies should confirm the new role of this variable as a predictor of To in the elderly; if confirmed, the knee-extension strength could be a new tool in the decision-making process in the consultations of older patients with cancer.