Clinical Implication of HER2 Status in Hormone Receptor-Positive Mucinous Breast Cancer

Nomogram for predicting survival in patients with mucinous breast cancer undergoing chemotherapy and surgery: a population-based study

BACKGROUND

The prognosis of patients with mucinous breast cancer (MuBC) is affected by several factors, but the low incidence of MuBC makes it difficult to conduct extensive and in-depth studies. This study was designed to establish a prognostic model and verify its accuracy in patients with MuBC after chemotherapy and surgery to help develop personalized treatment strategies.

MATERIALS AND METHODS

Patients with MuBC who underwent chemotherapy and surgery from 2004 to 2015 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. The prognostic factors of patients with MuBC were investigated using a Cox proportional hazards regression analysis. Based on the identified factors, a nomogram was constructed to forecast the overall survival (OS) of patients at 3, 5, and 10 years. Internal (from SEER) and external (from Yunnan Cancer Center, YNCC) verification queues were used to verify the nomogram and demonstrate the predictive capacity of this model.

RESULTS

The study comprised 1668 MuBC patients from the SEER database and 107 from the YNCC. The nomogram included four characteristics: age, anatomical stage, surgical method, and radiotherapy. The concordance indices in the training, internal verification, and external verification queues were 0.680, 0.768, and 0.864, respectively. The calibration curves for the nomogram showed excellent agreement between the predictions and observations. This nomogram has good clinical application value according to the decision curve analysis.

CONCLUSIONS

The prognosis of patients with MuBC who have undergone chemotherapy and surgery can be forecasted using this nomogram, which would be beneficial to help create individualized treatment plans for the affected patients.

Identifying clinicopathological risk factors for regional lymph node metastasis in Chinese patients with T1 breast cancer: a population-based study

Objectives

To analyze clinicopathological risk factors and regular pattern of regional lymph node metastasis (LNM) in Chinese patients with T1 breast cancer and the effect on overall survival (OS) and disease-free survival (DFS).

Materials and methods

Between 1999 and 2020, breast cancer patients meeting inclusion criteria of unilateral, no distant metastatic site, and T1 invasive ductal carcinoma were reviewed. Clinical pathology characteristics were retrieved from medical records. Survival analysis was performed using Kaplan-Meier methods and an adjusted Cox proportional hazards model.

Results

We enrolled 11,407 eligible patients as a discovery cohort to explore risk factors for LNM and 3484 patients with stage T1N0 as a survival analysis cohort to identify the effect of those risk factors on OS and DFS. Compared with patients with N- status, patients with N+ status had a younger age, larger tumor size, higher Ki67 level, higher grade, higher HR+ and HER2+ percentages, and higher luminal B and HER2-positive subtype percentages. Logistic regression indicated that age was a protective factor and tumor size/higher grade/HR+ and HER2+ risk factors for LNM. Compared with limited LNM (N1) patients, extensive LNM (N2/3) patients had larger tumor sizes, higher Ki67 levels, higher grades, higher HR- and HER2+ percentages, and lower luminal A subtype percentages. Logistic regression indicated that HR+ was a protective factor and tumor size/higher grade/HER2+ risk factors for extensive LNM. Kaplan-Meier analysis indicated that grade was a predictor of both OS and DFS; HR was a predictor of OS but not DFS. Multivariate survival analysis using the Cox regression model demonstrated age and Ki67 level to be predictors of OS and grade and HER2 status of DFS in stage T1N0 patients.

Conclusion

In T1 breast cancer patients, there were several differences between N- and N+ patients, limited LNM and extensive LNM patients. Besides, HR+ plays a dual role in regional LNM. In patients without LNM, age and Ki67 level are predictors of OS, and grade and HER2 are predictors of DFS.

Effect of postoperative radiotherapy in women with localized pure mucinous breast cancer after lumpectomy: a population-based study

Purpose

Pure mucinous breast cancer is a rare subtype of invasive breast cancer with favorable prognosis, in which the effect of postoperative radiotherapy remains unclear. We aimed to investigate the prognostic value of postoperative radiotherapy in women with localized pure mucinous breast cancer after lumpectomy.

Methods

We conducted a retrospective cohort study to compare the effectiveness of postoperative radiotherapy (RT) and omitting postoperative radiotherapy (non-RT) in patients with first primary T1-2N0M0 (T ≤ 3 cm) pure mucinous breast cancer who underwent lumpectomy between 1998 and 2015 using the Surveillance, Epidemiology, and End Results (SEER) database. Breast cancer-specific survival (BCSS) was compared between RT and non-RT groups using Kaplan–Meier method and Cox proportional hazards regression model. Propensity score matching (PSM) was carried out to balance cohort baselines. In addition, an exploratory analysis was performed to verify the effectiveness of RT in subgroup patients.

Results

Of 7832 eligible patients, 5352 (68.3%) underwent lumpectomy with postoperative RT, 2480 (31.7%) received lumpectomy without postoperative RT. The median follow-up duration was 92 months. The median age was 66 years in the RT group and 76 years in the non-RT group.The 15-year BCSS was 94.39% (95% CI, 93.08% to 95.35%) in the RT group versus 91.45%(95% CI, 88.93% to 93.42%) in the non-RT group (P < 0.001). The adjusted hazard ratio for BCSS was 0.64 (95% CI, 0.49 to 0.83; P = 0.001) for RT group versus non-RT group. After propensity score matching, similar results were yielded. Adjuvant RT reduced the 15-year risk of breast cancer death from 7.92% to 6.15% (P = 0.039). The adjusted hazard ratio for BCSS were 0.66 (95%CI, 0.47 to 0.92; P = 0.014) for RT group versus non-RT group. The benefit of RT was well consistent across subgroup patients.

Conclusion

Among women with T1-2N0M0 (tumor size ≤ 3 cm) pure mucinous breast cancer, the addition of RT after lumpectomy was significantly associated with a reduced incidence of breast cancer death compared with non-RT, and the magnitude of benefit may be modest. This suggests that postoperative RT is recommended in the treatment of localized pure mucinous breast cancer.

A novel nomogram and risk classification system for predicting lymph node metastasis of breast mucinous carcinoma: A SEER-based study

BACKGROUND

Mucinous breast cancer (MBC) is a rare disease, and patients with lymph node metastasis (LNM) have a poor prognosis. We aimed to explore the predictive factors of LNM and to construct a nomogram for predicting the risk of LNM and to identify the suitable axillary surgery for patients with diverse risks.

PATIENTS AND METHODS

Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Chi-square and rank-sum tests were used to analyze the differences between groups. Survival analysis was performed with Kaplan-Meier curves and log-rank tests. Independent factor identification and nomogram construction were performed with logistic regression analysis. The nomogram was qualified with a discrimination and calibration plot. Propensity score matching was performed to balance the disparities between groups.

RESULTS

Patients with metastatic lymph nodes have a worse prognosis. Univariate and multivariate analyses indicated that tumor size, grade, and age were independent risk factors for LNM. The nomogram constructed with these three factors can predict the risk of LNM with high accuracy (AUC: 0.767, 95% CI: 0.697-0.838) and good calibration. Based on the nomogram, a risk classification system satisfactorily stratified the patients into 3 groups with diverse risks of LNM. In the low-risk group, there were no significant differences between sentinel lymph node biopsy and no axillary surgery. In the middle- and high-risk groups, both SLNB and axillary lymph node dissection were superior to no axillary surgery, with similar survival benefits.

CONCLUSIONS

The nomogram based on tumor size, grade, and age could conveniently and accurately predict the risk of LNM in MBC and assist clinicians in optimizing surgical strategies.

Overall Survival in Patients with Mucinous Carcinoma of Breast: A Population-Based Study

Purpose

Mucinous carcinoma of the breast (MCB) is a rare malignant tumour. Therefore, it is urgent to establish a survival prediction model for MCB patients.

Methods

Clinicopathological and follow-up data of MCB patients diagnosed between 2010 and 2015 were retrieved from the Surveillance, Epidemiology, and End Result (SEER) database. The significant factors were screened out and generated Kaplan-Meier (K-M) curves for each prognostic factor. Additionally, these factors were then utilized to build a nomogram for predicting 3-, 4-, and 5-year overall survival (OS) of MCB patients. The nomogram was evaluated using calibration curves, receiver operating characteristic (ROC) curves and decision curve analysis (DCA).

Results

Moreover, a total of 4326 MCB patients were retrieved. Age, American Joint Committee on Cancer (AJCC) stage, surgery, radiotherapy and bone metastasis were identified as independently prognosis factors for OS. The corresponding areas under the ROC curves (AUCs) of the nomogram at 3, 4 and 5 years in the training and validation set were 0.770, 0.788, 0.805, 0.778, 0.797, and 0.802, respectively. The calibration curves and DCA revealed that the prediction model had an excellent performance. Finally, the risk stratification system confirmed that the powerful role of the nomogram in distinguishing results and risk stratification.

Conclusion

Briefly, the nomogram incorporating various clinicopathological indicators was established for MCB patients and may facilitate clinical decision-making.

Histopathological analysis of mucinous breast cancer subtypes and comparison with invasive carcinoma of no special type

Mucinous breast cancer (MBC) is a rare histological type of breast cancer characterized primarily by mucin's production and extracellular presence. MBC is usually associated with a better prognosis than other invasive breast neoplasms. Because of the low prevalence, MBC biology is not well understood. The aim of the present study was to introduce the last 2-year experience regarding MBC pathological diagnostics in our clinical center and comparison of the obtained data with invasive breast carcinoma of no special type (NST) comprising the most common invasive breast cancer. We identified 24 MBC cases representing 3.09% of all 766 invasive breast cancers, including 15 cases of pure type and 9 mixed MBCs. The median MBC patients' age at presentation was 65.5 years. Compared to NST, MBC presented a higher T stage with a statistically larger tumor median size, although lower regional lymph node involvement, tumor histological grade and TNM stage. MBC is a rare type of breast cancer, accounting for about 4% of all diagnosed breast cancers. Our findings are consistent with those published in recent years and show significant differences between MBC and NST cancer patients and also highlight differences between pure and mixed MBC, emphasizing the essence of their differentiation. MBC is associated with a better long-term prognosis than NST and is characterized by the less aggressive biological behavior expressed through favorable clinicopathologic features in terms of tumor grade, regional lymph node involvement and hormone receptor status.

Clinicopathological and Molecular Analysis of 45 Cases of Pure Mucinous Breast Cancer

Pure mucinous breast carcinoma (PMBC) is characterized by clusters of tumor cells floating in abundant extracellular mucin and can be classified into paucicellular (Type A) and hypercellular (Type B) subtypes. However, the clinicopathological and genomic differences between these two subtypes have not been well characterized. We retrospectively investigated the clinicopathologic features of 45 cases of surgically removed PMBC (31 Type A and 14 Type B). We also performed whole-exome sequencing (WES) in eight cases of PMBC. We found that Type B PMBC occurs at an older age and shows more aggressive clinical behavior than Type A. WES analysis revealed that HYDIN was the most frequently mutated gene in both types of PMBC. Although Type B PMBC showed a tendency toward more frequent genetic alterations, there were no statistically significant differences between the two subtypes in single nucleotide variants or insertions or deletions of bases associated with moderate or high effects. Our results provide additional evidence that PMBCs are clinicopathologically and genetically heterogeneous and lack pathognomonic genetic alterations. Further, Type B PMBC is more frequently associated with lymph node metastasis than Type A.

Adjuvant chemotherapy could benefit early-stage ER/PR positive mucinous breast cancer: A SEER-based analysis

Purpose

The aim of this study was to explore the value of adjuvant chemotherapy in patients with early-stage ER/PR-positive mucinous carcinoma.

Methods

We identified early-stage ER/PR-positive mucinous carcinoma patients in the Surveillance, Epidemiology, and End Results (SEER) database. We used propensity-score matching (PSM) analysis to eliminate selection bias and differences in baseline characteristics. Univariate and multivariate analyses were performed to identify significant prognostic factors. The primary outcomes were overall survival (OS) and breast cancer-specific survival (BCSS), which were evaluated with the Kaplan-Meier method.

Results

After propensity score matching, 805 pairs were selected. Patients with early-stage ER/PR-positive mucinous adenocarcinoma in the chemotherapy group had a better OS, but not BCSS, than those in the nonchemotherapy group after PSM (OS: p < 0.001; BCSS: p = 0.285). After stratifying by tumor size and lymph node status, adjuvant chemotherapy could significantly improve the OS of early-stage ER/PR-positive patients with tumors larger than 3 cm (p = 0.004) if they had negative lymph nodes (LNs). For patients positive LNs, the OS was significantly different between the chemotherapy group and the non-chemotherapy group when the tumors were larger than 1 cm (T = 1–2.9 cm, p = 0.006; T＞3 cm, p = 0.049, respectively).

Conclusion

Adjuvant chemotherapy maybe improves prognosis in patients with negative LNs and tumors larger than 3 cm, or patients with LNs metastasis and tumors larger than 1 cm. We suggest considering clinical characteristics meanwhile when deciding chemotherapy or not. Randomized controlled trials (RCT) are expected to confirm our results in the future.

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Propensity-score matching was used to narrow selection bias.

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Chemotherapy benefits patients with negative nodes and tumors larger than 3 cm.

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Chemotherapy benefits patients with positive nodes and tumors larger than 1 cm.

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Randomized controlled trials are expected in the future.

Genotype-phenotype associations in breast pathology: Achievements of the past quarter century

The first genotype-phenotype relationship in breast pathology developed in 1994 with the discovery of the CDH1 gene. This finding eventually provided biological insight into the characteristic morphology of invasive lobular carcinoma. Subsequent investigative efforts have uncovered additional molecular alterations largely responsible for the histology of several breast neoplasms including secretory carcinoma, adenoid cystic carcinoma, tall cell carcinoma with reversed polarity, fibroepithelial lesions, and most recently, adenomyoepithelioma. Evaluation of the genomic landscape of other special types of breast cancer with distinctive growth patterns, such as invasive mucinous carcinoma, have yet to uncover recurring cytogenetic and/or molecular alterations. Despite the lack of a hallmark alteration in mucinous carcinoma, it is important to note the relative decrease in PIK3CA mutations compared with invasive carcinoma of no special type. In this review, we describe the clinical and pathologic features of breast tumors with recognized genotype-phenotype correlations and summarize the molecular alterations of mucinous carcinoma.

Clinicopathologic characteristics of HER2-positive pure mucinous carcinoma of the breast

BACKGROUND

Pure mucinous carcinoma (PMC) is a rare type of breast cancer, estimated to represent 2% of invasive breast cancer. PMC is typically positive for estrogen receptors (ER) and progesterone receptors (PR) and negative for human epidermal growth factor receptor 2 (HER2). The clinicopathologic characteristics of HER2-positive PMC have not been investigated.

METHODS

Pathology archives were searched for PMC diagnosed from January 1999 to April 2018. Clinicopathologic data and microscopic findings were reviewed and compared between HER2-positive PMC and HER2-negative PMC. We also analyzed the differences in disease-free survival (DFS) and overall survival according to clinicopathologic parameters including HER2 status in overall PMC cases.

RESULTS

There were 21 HER2-positive cases (4.8%) in 438 PMCs. The average tumor size of HER2-positive PMC was 32.21 mm (± 26.55). Lymph node metastasis was present in seven cases. Compared to HER2-negative PMC, HER2-positive PMC presented with a more advanced T category (p < .001), more frequent lymph node metastasis (p = .009), and a higher nuclear and histologic grade (p < .001). Microscopically, signet ring cells were frequently observed in HER2-positive PMC (p < .001), whereas a micropapillary pattern was more frequent in HER2-negative PMC (p = .012). HER2-positive PMC was more frequently negative for ER (33.3% vs. 1.2%) and PR (28.6% vs. 7.2%) than HER2-negative PMC and showed a high Ki-67 labeling index. During follow-up, distant metastasis and recurrence developed in three HER2-positive PMC patients. Multivariate analysis revealed that only HER2-positivity and lymph node status were significantly associated with DFS.

CONCLUSIONS

Our results suggest that HER2-positive PMC is a more aggressive subgroup of PMC. HER2 positivity should be considered for adequate management of PMC.

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.