Physicians' Knowledge, Attitudes, and Barriers Toward Clinical Trial Participation in Türkiye: A Cross-Sectional Survey and Implications for Oncology Research Capacity.

BACKGROUND: Physicians influence clinical trial conduct and patient referral, yet country-specific evidence regarding their knowledge, attitudes, and perceived barriers in Türkiye remains limited. This evidence gap is especially relevant to oncology, where clinical trials are closely linked to therapeutic innovation and access to novel treatments. OBJECTIVE: This study evaluated physicians' clinical trial knowledge, experience, attitudes, perceived barriers, and motivational factors, and identified variables associated with positive attitudes toward clinical research. METHODS: A cross-sectional online survey was conducted between January 20 and March 7, 2025, targeting practicing physicians across Türkiye. Using a structured 23-item questionnaire, demographics, clinical trial experience, education, knowledge, attitudes, and perceived barriers were assessed. Descriptive statistics and ordinal regression analysis were performed. RESULTS: Among 195 respondents (54.4% female; median age, 39 years), 61.0% had participated in a clinical trial. No knowledge of suspected unexpected serious adverse reaction terminology and Phase I/early-phase trials was reported by 56.4% and 26.7%, respectively, whereas 89.8% considered clinical trials essential for generating medical knowledge. Frequently reported barriers included lack of sponsors (89.3%) and financial constraints (83.1%). Greater clinical trial knowledge was associated with more favorable attitudes (β = 1.051, SE = 0.237, p < 0.001). Oncology physicians had higher prior clinical trial participation than non-oncology physicians (85.5% vs 49.6%, p < 0.001), including after multivariable adjustment (OR 3.46, 95% CI 1.37-8.74, p = 0.009). CONCLUSION: Physicians in Türkiye have favorable attitudes toward clinical trials but face important knowledge, logistical, and institutional barriers. Strengthening clinical research education and organizational support may improve physician engagement and contribute to oncology research capacity.