BackgroundGeriatric syndromes may be more common in older cancer patients than in those without cancer. Geriatric syndromes can cause poor clinical outcomes. The Eastern Cooperative Oncology Group Performance Status (ECOG-PS) is often used as a clinically reported functional status score in oncology practice.MethodsOur study was designed as a cross-sectional study and included 218 older cancer patients. This study aimed to determine the prevalence and relationship of geriatric syndromes according to the ECOG-PS in older cancer patients.ResultsThe mean age of 218 participants was 73.0 ± 5.6 years, with 47.7% being women and 52.3% men in our study. ECOG-PS 0, 1, and 2 groups contained 51, 39, and 10% of the patients, respectively. The mean number of geriatric syndromes in the ECOG 0, 1, and 2 groups was 2.3 ± 2.2, 4.3 ± 2.4, and 5.7 ± 2.1, respectively (p < 0.001). After adjusting for age and sex, it was determined that dynapenia was 2.9 times, probable sarcopenia was 3.5 times, frailty was 4.2 times, depression was 2.6 times, malnutrition was 3.3 times, insomnia 2 was.2 times, falls was 2.5 times, and the risk of falling (TUG) was 2.4 times more likely in those with ECOG-PS 1 compared to those with ECOG-PS 0. In addition, it was found that dynapenia was 6 times, probable sarcopenia was 6.8 times, frailty was 10.8 times, depression was 3.3 times, malnutrition was 6.3 times, the risk of falling (Tinnetti Balance) was 28 times, and the risk of falling (TUG) was 13.6 times more likely in those with ECOG-PS 2 compared to those with ECOG-PS 0.ConclusionOur study found that the prevalence of geriatric syndromes increased as the ECOG-PS increased. Geriatric syndromes and their co-incidence were common in older cancer patients, even in normal performance status. Oncologists should incorporate geriatric syndromes into the decision-making process of cancer treatment to maximize the impact on clinical outcomes in older patients with cancer.