Association of HER2 Overexpression and Prognosis in Small (T1N0) Primary Breast Cancers

The Effect of Adjuvant Treatment in Small Node-negative HER2-positive Breast Cancer: Which Subgroup Will Benefit?

BACKGROUND

We conducted this study to evaluate whether patients with T1a/b, node-negative (N^-), human epidermal growth factor receptor 2-positive (HER2⁺) breast cancers benefited from adjuvant therapy, and explored better treatment strategies for these patients.

PATIENTS AND METHODS

Patients with T1a/b, N^-, HER2⁺ breast cancers during 2000 through 2004 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The Gray test was used to evaluate breast cancer-specific death (BCSD) and non-BCSD. To identify patients more suitable for chemotherapy, subgroup analyses were conducted according to tumor size and estrogen receptor (ER) status, and plots of hazard rate of death (HRD) were drawn to present the changes of BCSD.

RESULTS

A total of 2940 patients with T1a/b, N^-, HER2⁺ breast cancers were included; more patients in the T1b group received chemotherapy compared with the T1a group (65.18% vs. 29.30%; P < .001). Patients receiving chemotherapy did not benefit from it (5-year incidences of BCSD: 1.00% in the non-chemotherapy group vs. 1.18% in the chemotherapy group; P = .853). Compared with those in the T1a group, patients in the T1b group had similar prognosis (P = .532), whereas ER status was significantly associated with survival (P = .048). HRD had a peak in years 2 to 5, which was more obvious in the ER^- group.

CONCLUSION

Chemotherapy, which is mainly decided by tumor size, fails to render survival benefits for patients with T1a/b, N^-, HER2⁺ breast cancers. ER status, rather than tumor size, is important for clinicians to make adjuvant treatment decisions. The peak of BCSD occurs 2 to 5 years after diagnosis, and an at least 5-year follow-up is recommended for these patients.

The clinical and biological significance of HER2 over-expression in breast ductal carcinoma in situ: a large study from a single institution

BACKGROUND

Previous studies have reported up to 50% of ductal carcinoma in situ (DCIS), is HER2 positive, but the frequency of HER2-positive invasive breast cancer (IBC) is lower. The aim of this study is to characterise HER2 status in DCIS and assess its prognostic value.

METHODS

HER2 status was evaluated in a large series of DCIS (n = 868), including pure DCIS and DCIS associated with IBC, prepared as tissue microarrays (TMAs). HER2 status was assessed using immunohistochemistry (IHC) and chromogenic in situ hybridisation (CISH).

RESULTS

In pure DCIS, HER2 protein was over-expressed in 9% of DCIS (3+), whereas 15% were HER2 equivocal (2+). Using CISH, the final HER2 status was positive in 20%. In mixed DCIS, HER2 amplification of the DCIS component was detected in 15% with amplification in the invasive component of only 12%. HER2-positive DCIS was associated with features of aggressiveness (p < 0.0001) and more frequent local recurrence (p = 0.03). On multivariate analysis, combined HER2+/Ki67+ profile was an independent predictor of local recurrence (p = 0.006).

CONCLUSIONS

The frequency of HER2 positivity in DCIS is comparable to IBC- and HER2-positive DCIS is associated with features of poor prognosis. The majority of HER2 over-expression in DCIS is driven by gene amplification.

De-escalating treatment in the adjuvant setting in HER2-positive breast cancer

The decision to offer adjuvant therapy to patients with early-stage cancer relies on factors related to the risk of disease recurrence, degree of benefit with the proposed therapy and the associated risk of toxicities. For patients with stages II and III HER2-positive breast cancer, administering 1 year of trastuzumab plus comprehensive chemotherapy is the standard of care. However, the pivotal adjuvant trials had very few older patients and patients with small HER2-positive tumors. In this review, we will discuss the clinical data regarding strategies to de-escalate adjuvant systemic therapy in patients with early stage HER2-positive disease.

Optimal Management of Early and Advanced HER2 Breast Cancer

Approximately 15%-20% of breast cancer is HER2 positive, and patients with this subtype of disease historically had worse outcomes than patients with HER2-negative disease. However, the introduction of HER2-directed therapies has dramatically altered outcomes for these patients, especially for persons with early disease. However, despite these achievements, metastatic disease is still not curable. This review summarizes the current treatment approach for patients in the preoperative and adjuvant setting, including data regarding selecting the optimal chemotherapy partner as well as determining the duration and type of anti-HER-directed therapy. This article also reviews how to approach patients with advanced HER2-positive disease and discusses promising new therapies that are in development.

The evolving understanding of small HER2-positive breast cancers: matching management to outcomes

Systemic therapy for small (stage I) HER2-positive breast cancers has long posed a dilemma for clinicians, as the majority of these patients were excluded from the large adjuvant trastuzumab trials. However in the decade since those trials were reported, data have accumulated to suggest that recurrence risk for these small but biologically aggressive tumors is nontrivial. In this review, we summarize data from numerous cohort studies describing the outcomes of small HER2-positive tumors, mostly in the absence of HER2-directed therapy. We then examine the potential impact of HER2-directed treatment in this population, culminating in the recently published prospective study of paclitaxel/trastuzumab therapy. The landscape of next generation anti-HER2 therapies is quickly evolving; a role for some of these agents in the small HER2-positive subpopulation may also be on the horizon.

Early (<10 mm) HER2-Positive Invasive Breast Carcinomas are Associated with Extensive Diffuse High-Grade DCIS: Implications for Preoperative Mapping, Extent of Surgical Intervention, and Disease-Free Survival

BACKGROUND

The few publications on <10-mm invasive breast carcinomas have reported worse outcomes for women with human epidermal growth factor receptor 2 (HER2)-positive cancer compared with HER2-negative cases and indicated that the high risk of recurrence in HER2-positive cases is related to the high grade, hormone receptor negativity, and high proliferation index of the invasive tumor component.

METHODS

We studied the subgross morphology of such tumors in a consecutive series of 203 cases documented in large-format histology slides and worked up with detailed radiological-pathological correlation.

RESULTS

The invasive component was associated with a diffuse in situ component in 78 % of the HER2-positive and 26 % of HER2-negative tumors <10 mm in size (odds ratio [OR], 11.3936; P < .0001). The in situ component was of high grade in 75 % of HER2-positive and 9 % of HER2-negative cases (OR, 29.6000; P < .0001). Significant associations were also found between the HER2 positivity of the invasive component and diffuse combined lesion distribution (P > .0001), invasive tumor grade 3 (P = .0004), presence of vascular invasion (P = .0026), extensive disease (P = .0170), "not special" (ductal) histological tumor type (P = .0302), estrogen receptor negativity (OR, 7.8846; P < .0001), and high Ki67 proliferation index (OR, 5.0000; P = .0007). The HER2-positive tumors tended to be multifocal (OR, 2.000) and lymph node-positive (OR, 3.0147), but the tendency was not statistically significant.

CONCLUSIONS

The vast majority of <10-mm HER2-positive breast carcinomas exhibited a high-grade, diffuse, and extensive in situ component, which may explain the high risk of recurrence among these tumors.

Factors associated with the incidence of local recurrences of breast cancer in women who underwent conservative surgery

Conservative surgery is considered the procedure of choice for women who are affected by early stage tumours. The local recurrence of cancer as a consequence of breast tissue conservation is a growing concern. This study aimed to describe the sociodemographic and clinical profiles of women who had local recurrences of breast cancer after conservative surgery and to examine the associations between sociodemographic and clinical variables and the incidence of tumour recurrence in these women. The retrospective cohort included 880 women who were diagnosed with breast cancer and underwent conservative surgery between January 2000 and December 2010. Recurrences occurred in 60 patients, and the mean age of the women at diagnosis was 48.8 years. Predictive factors for local recurrence were young age (<39 years) (P = 0.028 and OR = 10.93), surgical margin involvement (P = 0.001 and OR = 3.66), and Her-2 overexpression (P = 0.045 and OR = 1.94). The establishment of sociodemographic and clinical characteristics might help to select optimum treatments, which is a crucial challenge for public health in Brazil, especially with regard to reductions of surgery and hospitalisation expenditures in the Unified Health System (Sistema Único de Saúde—SUS).

Endocrine sensitivity is decisive for patient outcome in small node-negative breast cancers (BC) (pT1a,b) - results from the Munich Cancer Registry

PURPOSE

In clinical routine, adjuvant systemic therapy in small node-negative (N0) BC is controversial, in particular in HER2-positive disease. We aimed to evaluate outcome of consecutive patients with small N0 BC in a population-based cancer registry and thus consequently substantiate indications for chemotherapy in those patient subgroups at increased relapse risk or poor survival.

METHODS

From 2002 to 2009 (median follow-up 6 years), 9707 primary breast cancer patients with N0 tumors <2 cm (pTis, pT1N0M0) were reported to the Munich Cancer Registry. Patients with pTis tumors (n = 1870) served as internal comparator. Time to progression, observed (OS) and relative survival rates (Kaplan-Meier estimates) are presented. Cox regression analysis was used to assess the influence of tumor size, age, HR-, and HER2-status.

RESULTS

10-year-OS for pTis was 94.0%. In HR-positive tumors it was 91.9% in pT1a, 90.6% in pT1b, and 86.8% in pT1c. In HR-negative tumors, rates were 91.7%, 86.8%, and 86.8%, respectively. In HER2-positive tumors it was 81.2%, 88.1%, and 86.7%, in HER2-negative 93.1%, 90.6%, and 86.0%, respectively. In the multivariate model, age, tumor size, and HR-status showed a significant impact on OS (HRneg. vs. HRpos.: hazard ratio 1.50 (95% CI; 1.12-1.99), while HER2-status was not an independent prognostic factor.

CONCLUSION

Prognosis of N0 tumors <1 cm is excellent, especially if they are HR-positive, even in HER2-positive cases. Weighing potential benefits vs. side-effects, there seems to be no need for chemotherapy in tumors <0.5 cm. In pT1b chemotherapy may be considered, if tumors are triple negative or HER2-positive and HR-negative. In pT1c guideline-based adjuvant therapy using all therapeutic options seems to be warranted.

Systemic therapy for early-stage HER2-positive breast cancers: time for a less-is-more approach?

Trastuzumab-based chemotherapy has dramatically improved outcomes for patients with all stages of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Additional HER2-directed agents that have recently been approved are also expected to improve outcomes. Patients with small, lymph node-negative, HER2-positive breast cancers who are treated with trastuzumab-based chemotherapy demonstrate especially favorable responses, with 5-year recurrence rates of <5%. In this review, recent data regarding response rates among patients with early-stage HER2-positive breast cancer treated with trastuzumab-based chemotherapy are discussed. This review supports future studies of the possible omission of chemotherapy in a subset of patients with HER2-positive cancers, specifically those that coexpress hormone receptors.