Analysis of Survival Data of Patient with Breast Cancer Using Cox Regression Model

Introduction & Breast cancer is the most common cancer in women and the second leading cause of cancer related mortality after lung cancer. Survival models, a regression equation that determines what the life of a patient with a particular disease affects. The survival of patients with breast cancer as one of the main criteria to measure the impact of cancer control and treatment can be accepted. So that the survival rate is an important indicator to assess the effectiveness of diagnosis and the treatment effect of breast cancer treatment. The aim of this study was to determine the survival rate of patients with breast cancer who referred to hospital by air force mission of the Islamic Republic, using a Cox regression model.
In this longitudinal study of 499 patients with breast cancer during the years 1389 to 1394 after surgery, treatment aids such as hormone therapy, chemotherapy and radiotherapy had been investigated, and clinical characteristics, treatment and condition of their survival were recorded.
The mean age (± SD) of patients was 3.50 (± 1.11) years. The most common type of malignancy were invasive duct carcinoma by 88% and 18% of patients with stage III disease had been admitted. One, two and five -year survival of the patient was 87%, 63% and 50%, respectively. Statistical analysis showed that age, tumor size, metastasis and hormone therapy was a significant relationship with the risk of death in these patients, so Cox regression survival model in this study, based on this proposal, and survival analysis based on it is done.
Survival following diagnosis of cancer has decreased with the increasing of age groups. The decreasing rate for age group of 75 is noticeable. This study shows that the risk of death in patients who undergo hormone therapy are much lower than patients who were not able to hormone therapy because patients who were treated with testosterone, estrogen and progesterone receptors were positive prognosis for this disease. As well as patients who have lymph nodes involved in the early stages of the disease were identified and receive appropriate treatment, life will be more. Therefore, education to early diagnosis of breast cancer in women must be considered and followed seriously.