Analysis Of Survival Factors Associated With Occult Breast Cancer And Construction Of A Predictive Nomogram: A Population-based Study

Objective: Occult breast cancer(OBC)is a rare type of breast cancer with a relatively unfavorable prognosis for patients,and its oncological behavior is still unclear.In this study,we propose to explore the prognostic factors and develop a clinical prognostic model with a wide range of applicability in order to accurately predict the overall survival(OS)of patients with OBC.Methods:Data were extracted from the Surveillance,Epidemiology,and End Results(SEER)database.LASSO and multivariate Cox regression analyses were used with the aim of assessing and identifying independent risk factors for OS in stage Ⅱ/Ⅲ OBC and stage Ⅳ OBC.All significant predictors and associated risk scores were combined to create a nomogram to assess the prognosis of stage Ⅱ/Ⅲ OBC.The consistency and discrimination of this nomogram was validated using C-index,ROC,calibration and survival curves respectively.Results: Ultimately,this study included 653 patients with stage Ⅱ/ⅢOBC and 169 patients with stage Ⅳ OBC.7 factors were identified by LASSO regression as significant factors for stage Ⅱ/Ⅲ OBC prognosis,namely age,ER status,PR status,mode of axilla lymph nodes surgery,number of regional positive lymph nodes,tumor stage and radiotherapy status;multivariate Cox regression analysis determined 4 variables as independent OS-related factors for stage Ⅱ/Ⅲ OBC,including age,mode of axilla lymph node surgery,number of positive lymph nodes and radiotherapy status.For patients with stage Ⅳ OBC,the 2 variables were PR status and distant metastasis mode,which were independent prognostic factors for OS.A nomogram of 3-year and 5-year OS in stage Ⅱ/Ⅲ OBC patients was conducted based on the independent prognostic factors for OBC.The Concordance index(C-index),for the training cohort was 0.73,and the area under the ROC curve(AUC)for 3-year and 5-year OS was 0.742 and 0.771;AUC for 3-year and 5-year OS in the validation cohort was 0.76 and 0.787,respectively.The calibration curves showed that the model had good consistency;and there was significant difference in the prognosis between the high-and low-risk groups according to the risk stratification of the nomogram(P < 0.0001).The prognosis of patients can be accurately and effectively predicted,which may facilitate clinical decision-making.Conclusions:1.For patients with stage Ⅱ/Ⅲ OBC,age,ER status,PR status,mode of axillary lymph node surgery,number of positive lymph nodes,tumor stage and radiotherapy status were independent influencing factors on the prognosis of stage II/III OBC,and the prognosis was relatively worse for patients aged≥60 years,receiving ALNS,number of positive lymph nodes >20 and not having radiotherapy.2.For patients with stage Ⅳ OBC,ER status,PR status,HER2 status,type of distant metastasis,type of breast surgery,radiotherapy and health insurance status were independent influencing factors for prognosis of stage IV OBC,while patients with stage IV OBC with non-positive PR and non-distant lymph node metastasis had a relatively worse prognosis.3.The nomogram in this study can come to predict the risk probability of3-year and 5-year overall survival in stage II/III OBC with high accuracy and provide a personalized survival tool for survival prognosis of stage II/III OBC patients.