Comprehensive geriatric assessment in older patients with cancer: an external validation of the multidimensional prognostic index in a French prospective cohort study

BACKGROUND: Older patients with cancer require specific and individualized management. The 3-group Multidimensional Prognostic Index (MPI) based on the Comprehensive Geriatric Assessment (CGA) has shown a predictive interest in terms of mortality. The objective of our study was to assess the prognostic value of MPI for 1-year mortality in an external prospective French cohort of elderly patients with cancer. METHODS: From March 2015 to March 2017 a prospective single-center cohort study enrolled all patients with cancer, aged 75 years and older referred to the geriatric oncology clinic. We used a proportional hazard model for 1-year mortality adjusted for age, sex, tumor sites and metastatic status. C-statistics were used to assess the incremental predictive value of MPI index to these risk factors. RESULTS: overall, 433 patients underwent CGA with MPI (women 42%; mean age 82.8 ± 4.8 years). The most common tumor sites were prostate (23%), skin (17%), colorectum (15%) and breast (12%); 29% of patients had a metastatic disease; 231 patients (53%) belonged to the “MPI-1” group, 172 (40%) to the “MPI-2” group and 30 patients were classified in the “MPI-3” group. One-year mortality rate was 32% (23% in MPI-1, 41% in MPI-2 and 53% in MPI-3, p = 0.024). All domains of MPI except cognition and living status were significantly associated with mortality at one-year, as well as tumor sites and metastatic status. Higher MPI was associated with a higher mortality risk (adjusted HR 1.56 [95%CI 1.70–2.09] and 1.72 [1.33–2.22] for MPI groups 2 and 3 compared to 1; p < 0.0001). CONCLUSIONS: In addition to established risk factors, MPI improves risk prediction of 1-year mortality. This practical prognostic tool may help to optimize management of these vulnerable patients.