Nomogram predicts survival and surgical benefits for patients with breast cancer with initial bone metastasis: A population-based study

Background: Primary stage IV breast cancer is associated with a poor prognosis. At present, the value of local surgical treatment for patients with stage IV breast cancer remains uncertain; therefore, treatment principles remain controversial. Because of the high heterogeneity of these patients, it is often difficult to evaluate their prognoses. As a result, this study aimed to establish a prognostic nomogram to evaluate the prognosis of patients with breast cancer experiencing primary bone metastasis.Methods: The clinical characteristics and follow-up data of patients with primary breast cancer and bone metastasis from 2010 to 2018 were collected from the Surveillance, Epidemiology, and End Results database and from 2013 to 2021 at the Peking Union Medical College Hospital. Patients were divided into training and validation groups. Multivariate Cox regression analysis was used to identify the independent prognostic variables for predicting cancer-specific survival (CSS). On the basis of these independent risk factors, a nomogram was developed and used calibration curves to evaluate its accuracy. Patients were divided into three risk groups according to their scores and surgery-related survival curves plotted using the log-rank test.Results: Overall, 6372 patients were included, with 6319 from the Surveillance, Epidemiology, and End Results database and 53 from the Peking Union Medical College Hospital Breast Surgery Department. Multivariate analysis showed that age, race, marital status, grade, tumor stage, estrogen receptor status, progesterone receptor status, human epidermal growth factor receptor 2 status, and burden of other metastatic lesions were all associated with CSS. Based on these results, a nomogram that predicted the 1-, 3-, and 5-year CSS rates in patients with primary breast cancer and bone metastasis (concordance index > 0.69) was developed. After dividing patients into low-risk, high-risk, or super-high-risk groups based on nomogram scoring criteria, survival analysis revealed that patients in the low- and high-risk groups had significant survival benefits from primary focal surgery.Conclusion: Independent risk factors for primary breast cancer in patients with bone metastasis were analyzed and a nomogram established to predict CSS. The prognostic tool derived in this study can assist clinicians in predicting the survival and surgical benefits of these patients through scoring, thereby providing further guidance for treatment strategies.