Abstract A101: The impact of dementia on cancer treatment decision-making, cancer treatment, and survival
Authors: Silverio Yaelin Caba , Liu Bian , Taioli Emanuela , Dharmarajan Kavita 
Published: September 2020

Abstract
Introduction: Dementia and cancer are common conditions affecting older adults. Yet, little is known about the effect of dementia on cancer treatment decision-making and the subsequent health outcomes in people diagnosed with cancer. We performed a mini review of the recent literature to assess the current knowledge and gaps on the impact of dementia on cancer treatment decision-making, treatment received, and survival. Methods: A systematic search of the PubMed database with keywords “dementia,” “cancer,” “treatment decision-making,” and “management” was performed to identify studies on older adults with a diagnosis of dementia before a diagnosis of cancer and/or comorbid cancer and dementia published in the English language from January 2004 to December 2018. We used the Mixed Methods Appraisal Tool to critically appraise the methodological quality of studies. We conducted meta-analyses wherever quantitative elements could be extracted to derive the summary odds ratios (ORs) and hazard ratios (HRs). Results: There were 55 studies (out of 829 from the initial search) included in the final full text-review. Health professionals, care givers, and patients with dual cancer and dementia tended to prefer less aggressive care and gave higher priority to quality of life over life expectancy. However, they also faced unique challenges. The decision-making processes varied widely among health professionals because of differences in personal opinion, lack of specific guidelines, difficulty in obtaining informed consent, and expectations of patient discomfort. Consistent with previously published findings on decision-making preferences, the meta-analysis showed that people with dementia were less likely to receive chemotherapy (OR=0.32 (95% CI: 0.31 to 0.35), nstudies=12), radiation therapy (OR=0.56 (95% CI: 0.18 to 1.78), nstudies=6), and surgery (OR=0.61 (95% CI: 0.34 to 1.08), nstudies=5) than other treatment. In addition, people with cancer and dementia had greater odds of receiving no treatment versus any treatment (OR=4.25 (95% CI: 1.65 to 10.90), nstudies=5). Older adults with both cancer and dementia had worse survival than those with cancer alone (HR =1.97 (95% CI: 1.67 to 2.31), nstudies=19). Conclusions: Our review showed that an underlying dementia diagnosis was associated with greater odds of receiving less and no cancer treatment, and with worse survival. Current practices in treatment-decision making and overall cancer management for patients with the dual diagnosis are inconsistent. There is an urgent need for guidelines in this growing population of cancer and dementia patients.
Citation Format: Yaelin Caba Silverio, Bian Liu, Emanuela Taioli, Kavita Dharmarajan. The impact of dementia on cancer treatment decision-making, cancer treatment, and survival [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A101.