Background: Breast cancer is the most common cancer in women, with different survival rates depending on the patients’ characteristics. Objectives: This study aimed to evaluate breast cancer patients’ characteristics and survival rates in the southeast of Iran. Methods: The recorded data of breast cancer patients treated were collected from 2004 to 2020 in the Radiation Oncology Department of Kerman University of Medical Sciences, Iran. Overall survival (OS) was estimated using the Kaplan-Meier method. The log-rank test was used to compare OS based on various factors. Three modeling strategies were considered to examine the patients’ survival using multiple Cox regression models. Results: The study included 309 patients who met the inclusion criteria; 153 (49.5%) were under 51 years of age. Luminal A intrinsic subtype accounted for 18.8% of cancer patients. Five- and 10-year OS rates were 86% and 63%, respectively. Five- and 10-year disease-free survival (DFS) rates for nonmetastatic patients were 82% and 60%, respectively. Multiple Cox regression showed that the percentage of the involved dissected lymph nodes, group stage, T-stage, M-stage, locoregional recurrence, and luminal subtype were independent prognostic factors for survival. Conclusions: Based on the results, the percentage of breast cancer patients under 50 years old is higher in the southeast of Iran compared to Western countries. In addition, the prevalence of the luminal A subtype is lower than in other regions. The survival results were consistent with other studies.