Clinicopathological characteristics and genomic profiling of pure mucinous breast cancer.

PURPOSE: Pure mucinous breast cancer (PMC) is a rare histological type with a favourable prognosis. However, cases with recurrence have been reported and diagnosed in clinical practice. The mechanisms underlying PMC recurrence remain unknown. In this study, we aimed to identify the prognostic factors associated with PMC. MATERIALS AND METHODS: A total of 166 patients diagnosed with PMC were included. We compared the clinicopathological characteristics between patients with and without recurrence. The 21-gene assay was performed in 10 patients with recurrence and 20 TNM stage-matched patients without recurrence. Whole-exon sequencing was performed in 12 PMC primary tumours and four positive lymph nodes (LNs). RESULTS: Tumour size, lymph node status and TNM staging differed significantly between recurrent group and non-recurrent group. And the 21-gene recurrence scores did not differ significantly between recurrent group and its TNM stage-matched non-recurrent group. The most frequently mutated genes in the primary tumours of regional LN-positive PMCs were ADCY10 (3/6) and SHANK3 (3/6), and they more recurrently harboured gains of 15q23, 17q23.2 and 20p11.21, and loss of 21p11.2. And these alterations were not detected in primary tumours of regional LN-negative PMCs. CONCLUSION: TNM stage is an important prognostic factor in PMC. Although we revealed that regional LN-positive PMCs show increased occurrence of duplication variants at 15q23, 17q23.2 and 20p11.21, and deletion variants at 21p11.2. Further investigation, including multi-omics studies, are needed and may provide additional insights into the nature of PMC.

[The predicting value of the 8th edition of American Joint Committee on Cancer staging manual in mucinous breast cancer].

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) χ(2), 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 χ(2): 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.

Omission of adjuvant radiotherapy following breast-conserving surgery for elderly women with early-stage pure mucinous breast carcinoma.

BACKGROUND: We aimed to ascertain population-based practice patterns and survival outcomes of postoperative radiotherapy following breast conserving-surgery (BCS) in elderly women (aged ≥65 years) with early-stage pure mucinous breast carcinoma (PMBC). METHODS: Patients aged ≥65 years diagnosed with T1-2N0 and hormone receptor-positive PMBC between 1990 and 2010 were identified from the Surveillance, Epidemiology, and End Results database. Binomial logistic regression, Kaplan-Meier method, Multivariate Cox proportional hazards models, and propensity score matching (PSM) were used for statistical analysis. RESULTS: We enrolled 3416 patients, including 1225 (35.9%) and 2191 (64.1%) in the no-radiotherapy and radiotherapy cohorts, respectively. The percentage of patients receiving postoperative radiotherapy following BCS was significantly lower after 2004 (59.5% between 2004 and 2010), relative to that before 2004 (71.1% between 1990 and 2003; P < 0.001). Before PSM, the 10-year breast cancer-specific survival (BCSS) rates were 98.1 and 93.2% for patients with and without postoperative radiotherapy (log-rank test, P < 0.001), respectively. In the PSM cohort, receiving postoperative radiotherapy was associated with better BCSS rates, with 10-year BCSS rates of 97.6 and 94.5% in patients with and without postoperative radiotherapy, respectively (log-rank test, P = 0.001). Multivariate Cox proportional analysis indicated that receiving postoperative radiotherapy was an independent factor associated with better BCSS before (P < 0.001) and after PSM (P = 0.001), relative to those not receiving postoperative radiotherapy. CONCLUSIONS: This study shows a decreasing utilization of postoperative radiotherapy following BCS of elderly PMBC patients over time. However, postoperative radiotherapy following BCS should be administered for elderly women with PMBC owing to independent association with better survival.

The predicting value of the 8th edition of American Joint Committee on Cancer staging manual in mucinous breast cancer / 中华肿瘤杂志

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.