Objective: The current study aimed to evaluate the predictive performances of anatomic staging system (AS) and prognostic staging system (PS) proposed in the 8th edition American Joint Committee on Cancer (AJCC) staging manual in patients with pure mucinous breast cancer (PMBC). Methods: Clinicopathologic features and follow-up information were collected from a total of 3628 patients with PMBC. Breast cancer-specific survival (BCSS) were compared among patients in different stage groups. Likelihood ratio (LR) χ², Akaike information criterion (AIC) and Harrell′s concordance index (C-index) were used to evaluate the predictive performances of AS and PS in PMBC. Results: In PMBC, BCSS was associated with tumor size (P=0.002), lymph node status (P=0.002), grade(P=0.003), PR status(P=0.017)and the receipt of radiation. Compared to AS, 1326 patients (37.54%) underwent stage change after applying PS, with 6.50% upstaged and 37.04% downstaged. There were significant differences in BCSS among patients of different stages under the AS and PS (P<0.001). However, PS was not superior to AS in predicting prognosis (AS vs PS, LR χ²: 16.41 vs 17.5; AIC: 357.44 vs 358.35; C-index, 0.72 vs 0.73, P=0.667). Conclusions Both of AS and PS proposed in the 8th edition American Joint Committee on Cancer (AJCC) staging manual were predictive factors in patients with PMBC. Compared with AS, the PS did not show superiority in prognosis prediction among patients with PMBC.

Purpose: Despite the rapid growing of cancer survivors, prior cancer history is a commonly adoptedexclusion criterion. Whether prior cancer will impact the survival of patients with advancedbreast cancer (ABC) remains uncertain. Materials and Methods: Patients with ABC diagnosed between 2004 and 2010 were identified using Surveillance,Epidemiology, and End Results (SEER) database. Timing, stage, and type were used to characterizeprior cancer. Multivariable analyses using propensity score–adjusted Cox regressionand competing risk regression were conducted to evaluate the prognostic effect of priorcancer on overall survival (OS) and breast cancer-specific survival (BCSS). Results: A total of 14,176 ABC patients were identified, of whom 10.5% carried a prior cancer history.The most common type of prior cancer was female genital cancer (32.4%); more than half(51.7%) were diagnosed at localized stage; most were diagnosed more than 5 years (42.9%)or less than 1 year (28.3%) prior to the index cancer. In multivariate analyses, patients withprior cancer presented a slightly worse OS (hazard ratio, 1.18; 95% confidence interval [CI],1.07 to 1.30; p=0.001) but a better BCSS (subdistribution hazard ratio, 0.64; 95% CI, 0.56to 0.74; p < 0.001). In subset analyses, no survival detriment was observed in patients withprior malignancy from head and neck or endocrine system, at in situ or localized stage, ordiagnosed more than 4 years. Conclusion Prior cancer provides an inferior OS but a superior BCSS for patients with ABC. It does notaffect the survival adversely in some subgroups and these patients should not be excludedfrom clinical trials.

Purpose: This retrospective study aimed to evaluate the distribution pattern and prognostic value of 21-gene recurrence score (RS) in Chinese patients with mucinous breast cancer (MC) and compared with infiltrating ductal carcinoma (IDC). Materials and Methods: Patients diagnosed with MC or IDC from January 2010 to January 2017 were retrospectively recruited. Reverse transcriptase–polymerase chain reaction assay of 21 genes was conducted to calculate the RS. Univariate and multivariate analyses were performed to assess the association between RS and clinicopathological factors. Survival outcomes including disease-free survival (DFS) and overall survival (OS) were estimated by Kaplan-Meier method and compared by log-rank test. Results: The MC cohort included 128 patients and the IDC cohort included 707 patients. The proportions of patients with a low (RS < 18), intermediate (18-30), or high risk (RS > 30) were 32.0%, 48.4%, and 19.5% in MC cohort, and 26.9%, 46.8% and 26.3% in IDC cohort. The distribution of RS varied significantly according to different Ki-67 index and molecular subtype in both cohorts. Moreover, the receipt of chemotherapy was associated with RS in both cohorts. Among patients with MC, tumor stage was related to the DFS (p=0.040). No significant differences in DFS and OS were found among MC patients in different RS risk groups (OS, p=0.695; DFS, p=0.926). Conclusion RS was significantly related to Ki-67 index and molecular subtypes in MC patients, which is similar in IDC patients. However, RS was not able to predict DFS and OS in patients with MC.