Background: COVID-19 pandemic has caused fear all around the world. With people avoiding hospitals, there has been a significant decrease in outpatient clinics. In this study, we aimed to compare and explore the first-peak of the pandemic period by studying its effects on patient applications, new diagnoses, and treatment approaches in a non-infected hospital. Methods: We collected data from the first peak of the pandemic period in Turkey, from the pandemic’s declaration (March 11, 2020) to social normalization (June 1, 2020), and compared it with data from a pre-pandemic period with a similar length of time. We analyzed the data of breast cancer patients from application to surgery. Results: The data of 34,577 patients were analyzed for this study. The number of patients who applied to outpatient clinics decreased significantly during the pandemic period. After excluding control patients and benign disorders, a figure was reached for the number of patients who had a new diagnosis of breast cancer (146 vs 250), were referred to neoadjuvant treatment (18 vs 34), and were treated with surgery (121 vs 229). All numbers decreased during the pandemic period, except for surgeries after neoadjuvant treatment (29 vs 27). Surgical treatment approaches also changed. However, the rate of newly diagnosed breast cancer patients treated with surgery was similar in both periods. None of these patients were diagnosed with COVID-19 or died during the pandemic. Conclusion: This study shows that non-infected hospitals can be useful in avoiding delays in the surgical treatment of cancer patients.