PURPOSE: Clinical experience suggests that functional decline (FD) during treatment may have a major adverse impact on outcome. Geriatric assessment of older patients before cancer treatment is usually based on use of a screening tool (such as G8) followed by comprehensive geriatric assessment (CGA). However, many oncology teams cannot implement geriatric oncology management due to non-availability of geriatricians. Consequently, we decided to evaluate whether a procedure using G8 and routinely available factors could help oncologists foresee the outcome in patients >/=70: we firstly evaluated whether functional decline is a determinant of early death, then searched for predictors of early functional decline (measured before initiation of the second cycle of chemotherapy), including G8 but voluntarilly excluding CGA. METHODS: We tested the value of clinical, biological factors and early FD to predict early death on a cohort of 292 patients (>/=70years) treated with first-line chemotherapy. We then used a logistic regression model to search for pretreatment predictors of FD, including the same factors and G8 but excluding CGA. RESULTS: FD occurred in 48 patients. In multivariate analyses, early FD (OR=4.13, 95% CI [1.89; 9.04], p<.01), disease extension (OR=4.55, 95% CI [1.96; 10.57]; p<.01), and being male (OR=2.59, 95% CI [1.12; 5.97], p =.02) were significant prognostic factors for early death; G8 was the only significant factor associated with FD (OR=4.38, 95% CI [1.28; 14.92], p=.018). CONCLUSIONS: FD has an important prognostic significance in patients >/=70 treated with chemotherapy, and G8 predicts for its occurrence. These data reinforce the routine use of G8 in the management of these patients.Read less <