Introduction: Structural disparities between different Brazilian regions in public health system cause patients to migrate in search of better conditions to treat their diseases. Besides patient's discomfort, there is a concentration of care in large centres, causing overload to current capacity.
Objective: To evaluate migratory flow and associated factors in a reference service in oncology.
Methods: Cross-sectional study conducted at a referral oncology service in Great ABC region of São Paulo. Patients were interviewed, and clinical and demographic data collected.
Results: Between March-July 2016, 217 patients were included. Analysis showed a divergence between the postal code registered in the medical record and that recorded during the interview in approximately 10% of cases. Of these, 42.9% were residents of other states. Search for treatment motivated most patients to seek service outside their city.
Conclusion: Results reflect the informal search for medical care outside the home area. Besides the direct impact on patients' quality of life, migratory flow has an economic-social impact because these patients place a burden and impose costs on services of cities where they do not perform their responsibilities as citizens. Confirmation of the existence of a significant migratory flow demonstrates the need to discuss restructuring public health policies.