ImportanceCancer was a common noncommunicable disease in Syria before the present conflict and is now a major disease burden among 3.6 million Syrian refugees in Turkey. Data to inform health care practice are needed.ObjectiveTo explore sociodemographic characteristics, clinical characteristics, and treatment outcomes of Syrian patients with cancer residing in the southern border provinces of Turkey hosting more than 50% of refugees.Design, Setting, and ParticipantsThis was a retrospective hospital-based cross-sectional study. The study sample consisted of all adult and children Syrian refugees diagnosed and/or treated for cancer between January 1, 2011, and December 31, 2020, in hematology-oncology departments of 8 university hospitals in the Southern province of Turkey. Data were analyzed from May 1, 2022, to September 30, 2022.Main Outcomes and MeasuresDemographic characteristics (date of birth, sex, and residence), date of first cancer-related symptom, date and place of diagnosis, disease status at first presentation, treatment modalities, date and status at last hospital visit, and date of death. The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision and International Classification of Childhood Cancers, Third Edition, were used for the classification of cancer. The Surveillance, Epidemiology, and End Results system was applied for staging. The diagnostic interval was defined as the number of days from first symptoms until the diagnosis. Treatment abandonment was documented if the patient did not attend the clinic within 4 weeks of a prescribed appointment throughout the treatment.ResultsA total of 1114 Syrian adult and 421 Syrian children with cancer were included. The median age at diagnosis was 48.2 (IQR, 34.2-59.4) years for adults and 5.7 (IQR, 3.1-10.7) years for children. The median diagnostic interval was 66 (IQR, 26.5-114.3) days for adults and 28 (IQR, 14.0-69.0) days for children. Breast cancer (154 [13.8%]), leukemia and multiple myeloma (147 [13.2%]), and lymphoma (141 [12.7%]) were common among adults, and leukemias (180 [42.8%]), lymphomas (66 [15.7%]), and central nervous system neoplasms (40 [9.5%]) were common among children. The median follow-up time was 37.5 (IQR, 32.6-42.3) months for adults and 25.4 (IQR, 20.9-29.9) months for children. The 5-year survival rate was 17.5% in adults and 29.7% in children.Conclusions and RelevanceDespite universal health coverage and investment in the health care system, low survival rates were reported in this study for both adults and children with cancer. These findings suggest that cancer care in refugees requires novel planning within national cancer control programs with global cooperation.