Negative Survival Impact of Occult Lymph Node Involvement in Small HER2-Positive Early Breast Cancer Treated by Up-Front Surgery

(1) Background: The independent negative prognostic value of isolated tumor cells or micro-metastases in axillary lymph nodes has been established in triple-negative breast cancers (BC). However, the prognostic significance of pN0(i+) or pN1mi in HER2-positive BCs treated by primary surgery remains unexplored. Therefore, our objective was to investigate the impact of pN0(i+) or pN1mi in HER2-positive BC patients undergoing up-front surgery on their outcomes. (2) Methods: We retrospectively analyzed 23,650 patients treated in 13 French cancer centers from 1991 to 2013. pN status was categorized as pN0, pN0(i+), pN1mi, and pNmacro. The effect of pN0(i+) or pN1mi on outcomes was investigated both in the entire cohort of patients and in pT1a-b tumors. (3) Results: Of 1771 HER2-positive BC patients included, pN status distributed as follows: 1047 pN0 (59.1%), 60 pN0(i+) (3.4%), 118 pN1mi (6.7%), and 546 pN1 macro-metastases (30.8%). pN status was significantly associated with sentinel lymph node biopsy, axillary lymph node dissection, age, ER status, tumor grade, and size, lymphovascular invasion, adjuvant systemic therapy (ACt), and radiation therapy. With 61 months median follow-up (mean 63.2; CI 95% 61.5-64.9), only pN1 with macro-metastases was independently associated with a negative impact on overall, disease-free, recurrence-free, and metastasis-free survivals in multivariate analysis. In the pT1a-b subgroup including 474 patients, RFS was significantly decreased in multivariate analysis for pT1b BC without ACt (HR 2.365, 1.04-5.36, p = 0.039) and for pN0(i+)/pN1mi patients (HR 2.518, 1.03-6.14, p = 0.042). (4) Conclusions: Survival outcomes were not adversely affected by pN0(i+) and pN1mi in patients with HER2-positive BC. However, in the case of pT1a-b HER2-positive BC, a negative impact on RFS was observed specifically for patients with pN0(i+) and pN1mi diseases, particularly among those with pT1b tumors without ACt. Our findings highlight the importance of considering the pN0(i+) and pN1mi status in the decision-making process when discussing trastuzumab-based ACt for these patients.

Adjuvant treatment with trastuzumab of patients with HER2-positive, T1a-bN0M0 breast tumors: A systematic review and meta-analysis

The benefit of adjuvant trastuzumab treatment in patients with HER2-positive breast tumors ≤ 10 mm without lymph node involvement (T1abN0) is insufficiently investigated. The aim of this systematic review and meta-analysis was to examine if adjuvant trastuzumab improves the prognosis in these patients. Databases were searched to identify interventional and observational studies evaluating the effect of trastuzumab on breast cancer specific survival (BCSS), disease free survival (DFS), distant recurrence free survival (DRFS), overall survival (OS) or recurrence free survival (RFS). Twelve studies examining the effect of trastuzumab and nine control studies without trastuzumab were identified (n = 6927). Median follow-up was 36-123 months. Significantly improved DFS (Hazard Ratio (HR) 0.14, p < 0.0001) and OS (HR 0.17, p = 0.011) were found for patients receiving trastuzumab and chemotherapy compared to no trastuzumab/chemotherapy based on four and two studies. The prognosis was good even for patients without trastuzumab treatment: 5-year DFS 88.3% and 5-year OS 95.9%.

Borderline indications for ovarian suppression: addressing uncertainties with patients

Ovarian function suppression (OFS) is a potentially life-saving treatment for young women diagnosed with high-risk hormonal-receptor (HR)+ early breast cancer (EBC), albeit one associated with significant side effects that may adversely affect quality of life. Of particular concern, this article raises a few borderline indications that were largely unaddressed in pivotal clinical trials but are still commonly encountered in daily practice. These, referred to here as 'borderline indications of OFS' remain a source of uncertainty for patients and physicians and are concisely addressed in this article.

Benefit of adjuvant chemotherapy and trastuzumab in patients with HER2-positive, node-negative breast tumors ≤ 10 mm: a nationwide study

PURPOSE

The purpose of this study was to evaluate the effect of chemotherapy and trastuzumab on invasive disease-free survival (iDFS) and overall survival (OS) in patients with human epidermal growth factor receptor 2 (HER2) positive, T1abN0 breast cancer.

METHODS

In the Danish Breast Cancer Group database, patients with HER2-positive, T1abN0 tumors diagnosed between 2007 and 2016 were identified. Cox proportional hazards analysis was performed to analyze the association between adjuvant chemotherapy and trastuzumab and iDFS and OS.

RESULTS

Of 605 patients included in the analyses, 465 patients received chemotherapy and trastuzumab and 140 patients did not. Chemotherapy and trastuzumab did not improve iDFS or OS significantly in adjusted analyses. 5-year iDFS was 92.3% vs. 89.9%, Hazard ratio (HR) 1.01 (p = 0.98), and 5-year OS was 97.4% vs. 94.3%, HR 0.60 (p = 0.15), chemotherapy and trastuzumab vs. no chemotherapy/trastuzumab. In unadjusted analyses, significant treatment benefit on OS was found in patients with T1b tumors. The largest absolute treatment benefits were found in patients with T1b tumors and estrogen receptor (ER) negative tumors, respectively, whereas treatment effects in patients with T1a tumors and ER-positive tumors, respectively, were limited.

CONCLUSION

Adjuvant chemotherapy and trastuzumab did not improve OS or iDFS significantly in patients with HER2-positive, T1abN0 breast cancers in adjusted analyses. In unadjusted analyses, significant OS benefit was found in patients with T1b tumors. The largest absolute benefit was observed in patients with T1b tumors and ER-negative tumors, respectively, whereas the effect was limited in patients with T1a tumors and ER-positive tumors, respectively.

Adjuvant therapy for HER2 positive pT1a-b pN0 breast cancer: A single center cohort study

Deciding if patients with small (≤1 cm), node-negative, human epidermal growth factor receptor 2 (HER2) positive breast cancer should receive adjuvant systemic therapy remains a challenge. No randomized clinical trials have examined the efficacy of trastuzumab in this setting. This prospective observational study aimed to investigate the choice of adjuvant systemic therapy in clinical practice in China.We prospectively collected data from patients with HER-2 positive breast cancer (less than 1 cm and node negative) patients who underwent breast cancer surgery at Shanxi Provincial People's Hospital Breast Center from January 1, 2017 to December 31, 2019, and retrospectively investigated the association between baseline clinicopathological features and treatment strategy, cardiotoxicity, and disease outcome.Of 168 eligible patients, 102 (60.7%) received adjuvant systemic therapy with trastuzumab (AST+T), 47 (28%) received adjuvant systemic therapy without trastuzumab (AST) and 19 (11.3%) did not receive adjuvant systemic therapy. Multivariate logistic regression analysis demonstrated that age, tumor size and hormone receptor status were significantly associated with treatment choice. Three-year invasive disease-free survival probability was 100%, 97.9% and 89.5% with AST+T, AST, and no therapy, respectively (P < .001).The majority of patients (60.7%) with pT1a-b pN0 HER2 positive breast cancer received adjuvant systemic therapy with trastuzumab, whereas only 11.3% did not receive any adjuvant systemic therapy. Tumor size, age and hormone receptor status influenced treatment choice. The 3-year invasive disease-free survival probability was significantly higher for patients who received adjuvant systemic therapy with trastuzumab compared with those who did not receive adjuvant systemic therapy. Cardiac adverse events were rare.

Treatment of small (T1mic, T1a, and T1b) node-negative HER2+ breast cancer - a review of current evidence for and against the use of anti-HER2 treatment regimens

INTRODUCTION

Since the advent of anti-HER2 therapies, evidence surrounding adjuvant treatment of small (T1mic, T1a, and T1b), node-negative, HER2-positive breast cancer (HER2+BC) has remained limited. Practices vary widely between institutions with little known regarding the added benefit of systemic therapy, including cytotoxic chemotherapy and HER2-directed treatments. Our group has set out to perform an extensive review of available literature on this topic.

AREAS COVERED

In this review, we examined HER2 biology, anti-HER therapies, outcome definitions, and available prospective and retrospective data surrounding the use of adjuvant therapy in those with small, node-negative, HER2+BC. For outcomes, we primarily explored breast cancer-specific survival (BCSS), invasive disease-free survival (iDFS), and overall survival (OS). We also investigated the incidence of adverse events with a particular focus on symptomatic and asymptomatic declines in left ventricular ejection fraction.

EXPERT OPINION

Retrospective data will likely be the main driver for future treatment decisions. Given what we know, high risk T1b and T1c subgroups derive measurable added benefit from HER2-guided combination therapies but it's not clear whether these benefits outweigh known risks associated with this combination therapy. For tumors ≤0.5cm (T1mic and T1a), treatment remains highly controversial with limited evidence available through retrospective analysis that suggest over-treatment may be occurring.

A comparison of local therapy alone with local plus systemic therapy for stage I pT1aN0M0 HER2+ breast cancer: A National Cancer Database analysis

BACKGROUND

Small invasive breast cancers (BCs) with tumor sizes ≤5 mm (T1a) are associated with an excellent prognosis without systemic therapy. Although HER2 overexpression (HER2+) is associated with a higher risk of recurrence and poorer clinical outcomes, in the absence of HER2 directed therapy, it remains unclear whether adjuvant systemic therapy is necessary in node-negative patients diagnosed with HER2+ invasive BCs ≤5 mm (pT1aN0M0).

METHODS

The National Cancer Database was searched to identify patients diagnosed with HER2+ pT1aN0M0 BCs from 2004 to 2017. The cohort was stratified by treatment status: local therapy alone or local plus adjuvant systemic therapy. A 1:1 propensity match was performed. Overall survival (OS) was analyzed using stratified multivariable Cox proportional hazards regression analyses.

RESULTS

Of the 8948 patients found, 4026 (45.0%) underwent surgery alone, and 4922 (55.0%) received surgery plus systemic therapy. Patients with either moderately differentiated (odds ratio [OR], 2.053; P < .001) or poorly/undifferentiated tumors (OR, 3.780; P < .001) or with the presence of lymphovascular invasion (OR, 3.351; P < .001) were more likely to have received systemic therapy. Propensity matching generated 1162 pairs of patients who were hormone receptor positive (HR+) and 748 pairs who were hormone receptor negative (HR-). Propensity matching effectively reduced selection bias between study groups. In the matched cohort, the addition of systemic therapy was not associated with superior OS (hazard ratio for HR+, 1.613; P = .107, and hazard ratio for HR- 1.319; P = .369) compared with patients who received local therapy alone.

CONCLUSIONS

In pT1aN0M0 HER2+ BC, the addition of adjuvant systemic therapy after surgical excision was not associated with improved OS compared with local therapy alone.

Benefits of adjuvant treatment including trastuzumab in HER2-positive pT1a-bN0M0 breast cancer: a systematic review and meta-analysis

BACKGROUND

Although trastuzumab has been shown to be beneficial for treating patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer, information regarding its benefits is limited to very low-risk cases with tumours ≤1 cm and without lymphatic metastases (pT1abN0). The present meta-analysis integrates information from literature and determines the benefit of trastuzumab in pT1abN0, HER2-positive breast cancer patients.

METHODS

PubMed, MEDLINE, and EMBASE databases were searched for studies published before Sep 30, 2019. Our primary endpoint was tumor recurrence, whether provided as overall or distant recurrences.

RESULTS

Seven studies involving 1,181 patients with pT1abN0, HER2-positive breast cancer were included in the systemic review. The median follow-up periods ranged from 37 to 78 months. The patients in the trastuzumab arm had generally inferior profiles such as higher rate of T1b, grade 3, and hormone negative cases, among available studies. Concomitant chemotherapy was more commonly applied in the trastuzumab arm (75-100% vs. 0-42%), and the hormone therapy application was similar in both arms (20-66%). In a pooled analysis of seven available studies, patients treated with trastuzumab had less overall recurrence relative to controls, with an odds ratio of 0.201 [95% confidence interval (CI): 0.100-0.404, P<0.001]. Five studies were available for a pooled analysis of distant recurrence. Although the results were not significant (P=0.115), distant recurrence did not occur in 237 patients treated with trastuzumab, but did occur in 16 out of 436 control patients. The odds ratio for distant recurrence was 0.328 (95% CI: 0.082-1.311).

CONCLUSIONS

The adjuvant treatment including trastuzumab was shown to reduce overall recurrence. Distant recurrence may also be reduced, as it did not occur among the 237 patients who underwent trastuzumab treatment.

Recent advances and optimal management of human epidermal growth factor receptor-2-positive early-stage breast cancer

With the introduction of anthracycline-based regimens, 5-year survival rates have significantly improved in patients with early-stage breast cancer. With the addition of trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor-2 (HER2), improvements in overall survival have been observed among patients with advanced HER2-positive disease. Subsequently, lapatinib, an orally bioavailable small molecule dual HER2- and EGFR/HER1-specific tyrosine kinase inhibitor, received Food and Drug Administration (FDA) approval in combination with capecitabine for patients with advanced HER2+ breast cancer. Then, pertuzumab in 2012 and ado-trastuzumab emtansine in 2013 were approved in the US and elsewhere based on evidence showing an improvement in survival outcomes in patients with mostly trastuzumab naïve or trastuzumab-exposed metastatic disease. The FDA also approved 1 year of extended adjuvant neratinib after chemotherapy and a year of trastuzumab for HER2-positive breast cancer on the basis of the ExteNET trial. The clinical benefit demonstrated by those drugs in advanced disease has triggered several adjuvant and neoadjuvant trials testing them in combination with chemotherapy, but also without conventional chemotherapy, using single or dual HER2-targeting drugs. In this article, we review the current data on the therapeutic management of HER2-positive early-stage breast cancer in the adjuvant and neoadjuvant setting. We also review the data the efficacy and safety of anthracycline-based and nonanthracycline-based adjuvant chemotherapy regimens combined with trastuzumab, and optimum chemotherapy regimens in small HER2-positive tumors.

Adjuvant chemotherapy in pT1ab node-negative triple-negative breast carcinomas: Results of a national multi-institutional retrospective study

BACKGROUND

Triple-negative breast cancers (TNBCs) are considered as associated with poor outcome, but prognosis of subcentimetric, node-negative disease remains controversial and evidence that adjuvant chemotherapy (CT) is effective in these small tumours remains limited.

PATIENTS AND METHODS

Our objective was to investigate the impact of CT on survival in pT1abN0M0 TNBC. Patients were retrospectively identified from a cohort of 22,475 patients who underwent primary surgery in 15 French centres between 1987 and 2013. As rare pathological types may display very particular prognoses in these tumours, we retained only the invasive ductal carcinomas of no special type according to the last World Health Organisation (WHO) classification which is the most common TNBC histological type. End-points were disease-free survival (DFS) and metastasis-free survival (MFS). A propensity score for receiving CT was estimated using a logistic regression including age, tumour size, Scarff Bloom and Richardson (SBR) grade and lymphovascular invasion.

RESULTS

Of a total of 284 patients with pT1abN0M0 ductal TNBC, 144 (51%) received CT and 140 (49%) did not. Patients receiving CT had more adverse prognostic features, such as tumour size, high grade, young age, and lymphovascular invasion. CT was not associated with a significant benefit for DFS (Hazard ratio, HR = 0.77 [0.40-1.46]; p = 0.419, log-rank test) or MFS (HR = 1.00 [0.46-2.19]; p = 0.997), with 5-year DFS and MFS in the group with CT versus without of 90% [81-94%] versus 84% [74-90%], and 90% [81-95%] versus 90% [83%-95%], respectively. Results were consistent in all supportive analyses including multivariate Cox model and the use of the propensity score for adjustment and as a matching factor for case-control analyses.

CONCLUSIONS

This study did not identify a significant DFS or MFS advantage for CT in subcentimetric, node-negative ductal TNBC. Although current consensus guidelines recommend consideration of CT in all TNBC larger than 5 mm, clinicians should carefully discuss benefit/risk ratio with patients, given the unproven benefits.

Benefit of adjuvant chemotherapy with or without trastuzumab in pT1ab node-negative human epidermal growth factor receptor 2-positive breast carcinomas: results of a national multi-institutional study

PURPOSE

Benefit of adjuvant trastuzumab-based chemotherapy for node-positive and/or >1 cm human epidermal growth factor receptor 2-positive (HER2+) breast carcinomas has been clearly demonstrated in randomized clinical trials. Yet, evidence that adjuvant chemotherapy with or without trastuzumab is effective in pT1abN0 HER2+ tumors is still limited. The primary objective of this study was to investigate the impact of adjuvant chemotherapy ± trastuzumab on outcome in this subpopulation.

PATIENTS AND METHODS

A total of 356 cases of pT1abN0M0 HER2 + breast cancers were retrospectively identified from a large cohort of 22,334 patients, including 1248 HER2+ patients who underwent primary surgery at 17 French centers, between December 1994 and January 2014. The primary end point was disease-free survival (DFS). A multivariate Cox model was built, including adjuvant chemotherapy, tumor size, hormone receptor status, and Scarff Bloom Richardson (SBR) grade.

RESULTS

A total of 138 cases (39%) were treated with trastuzumab-based chemotherapy, 29 (8%) with chemotherapy alone, and 189 (53%) received neither trastuzumab nor chemotherapy. Adjuvant chemotherapy ± trastuzumab was associated with a significant DFS benefit (3-year 99 vs. 90%, and 5-year 96 vs. 84%, Hazard ratio, HR 0.26 [0.10-0.67]; p = 0.003, logrank test) which was maintained in multivariate analysis (HR 0.19 [0.07-0.52]; p = 0.001). Metastasis-free survival was also increased (HR 0.25 [0.07-0.86]; p = 0.018, logrank test) at 3-year (99 vs. 95%) and 5-year (98 vs. 89%) censoring. Exploratory subgroup analysis found DFS benefit to be significant in hormone receptor-negative, hormone receptor-positive, and pT1b tumors, but not in pT1a tumors.

CONCLUSIONS

Adjuvant chemotherapy ± trastuzumab is associated with a significantly reduced risk of recurrence in subcentimeter node-negative HER2+ breast cancers. Most of the benefit may be driven by pT1b tumors.

Clinical Overestimation of HER2 Positivity in Early Estrogen and Progesterone Receptor-Positive Breast Cancer and the Value of Molecular Subtyping Using BluePrint

PURPOSE

Human epidermal growth factor receptor 2 (HER2) positivity is an important prognostic and predictive indicator in breast cancer. HER2 status is determined by immunohistochemistry and fluorescent in situ hybridization (FISH), which are potentially inaccurate techniques as a result of several technical factors, polysomy of chromosome 17, and amplification or overexpression of CEP17 (centromeric probe for chromosome 17) and/or HER2. In South Africa, HER2-positive tumors are excluded from a MammaPrint (MP; Agendia BV, Amsterdam, Netherlands) pretest algorithm. Clinical HER2 status has been reported to correlate poorly with molecular subtype. The aim of this study was to investigate the correlation of clinical HER2 status with BluePrint (BP) molecular subtyping.

METHODS

Clinico-pathologic and genomic information was extracted from a prospectively collected central MP database containing records of 256 estrogen receptor-positive and/or progesterone receptor-positive tumors. Twenty-one tumors considered HER2 positive on immunohistochemistry or FISH were identified for this study.

RESULTS

The median age of patients was 56 years (range, 34 to 77 years), with a median tumor size of 16 mm (3 to 27 mm). Four (19%) tumors were confirmed HER2-enriched subtype, six (29%) were luminal A, and 11 (52%) were luminal B. The positive predictive values of HER2/CEP17 ratio ≥ 2 and HER2 copy number ≥ 6 were only 29% and 40%, respectively. The differences in means for HER2/CEP17 ratio were significant between BP HER2-enriched versus luminal (P = .0249; 95% CI, 0.12 to 1.21) and MP high-risk versus low-risk tumors (P = .0002; 95% CI, 0.40 to 1.06).

CONCLUSION

Of the 21 tumors considered clinically HER2 positive, only four were HER2-enriched subtype with BP, indicating an overestimation of HER2 positivity. FISH testing has a poor positive predictive value.

Adjuvant Chemotherapy and Trastuzumab Is Safe and Effective in Older Women With Small, Node-Negative, HER2-Positive Early-Stage Breast Cancer

INTRODUCTION

The benefit of adjuvant trastuzumab with chemotherapy is well established for women with higher risk human epidermal growth factor receptor 2-positive (HER2⁺) breast cancer. However, its role in older patients with smaller, node-negative tumors is less clear. We conducted a retrospective, sequential cohort study of this population to describe the impact of trastuzumab on breast cancer outcomes and cardiac safety.

PATIENTS AND METHODS

Women ≥ 55 years with ≤ 2 cm, node-negative, HER2⁺ breast cancer were identified and electronic medical records reviewed. A no-trastuzumab cohort of 116 women diagnosed between January 1, 1999 and May 14, 2004 and a trastuzumab cohort of 128 women diagnosed between May 16, 2006 and December 31, 2010 were identified. Overall survival and distant relapse-free survival were estimated by Kaplan-Meier methods.

RESULTS

The median ages of the trastuzumab and no-trastuzumab cohorts were 62 and 64 years, respectively. More patients in the trastuzumab cohort had grade III (P = .001), lymphovascular invasion (P = .001), or estrogen receptor-negative (P < .001) cancers. The majority of the trastuzumab cohort received chemotherapy versus one-half of the no-trastuzumab cohort (98% vs. 53%; P < .0001). The median follow-up was 4 versus 9 years in the trastuzumab versus no-trastuzumab cohorts; therefore, outcomes at 4 years are reported. Despite the higher-risk tumor features in the trastuzumab group, the 4-year overall survival was 99% in both cohorts; the distant relapse-free survival was 99% versus 97% in the trastuzumab versus no-trastuzumab cohorts. Four (3.1%; 95% confidence interval, 1.0%-7.8%) women in the trastuzumab cohort and 1 in the no-trastuzumab cohort developed symptomatic heart failure. There were no cardiac-related deaths in either arm.

CONCLUSION

Following adjuvant trastuzumab with chemotherapy, selected older women with small, node-negative, HER2⁺ breast cancers have excellent disease control. The rate of cardiac events is low.

Daily Practice Management of pT1a-b pN0 Breast Carcinoma: A Prospective French ODISSEE Cohort Study

BACKGROUND

Most breast cancer (BC) tumors ≤10 mm have an excellent prognosis. The subgroups with a higher risk for distant recurrence requiring adjuvant systemic therapy are not precisely defined in current international guidelines.

PATIENTS AND METHODS

The OBSERVATOIRE DES PETITS CANCERS DU SEIN HER2 +/- (ODISSEE) study was a prospective, multicenter, cohort study that aimed to describe the daily adjuvant management and outcome of 616 patients with unifocal, invasive pT1a-b pN0 nonmetastatic BC who underwent surgery.

RESULTS

At the time of diagnosis, the median age of patients was 61 years. Tumor was detected on imaging or during a screening program in 397 patients (64.6%). Most patients (96%) underwent conservative surgery with sentinel node biopsy (89%), completed with axillary lymph node dissection in 15%. At inclusion, 82% of tumors were pT1b, 73% were pN0 (i-), 53% were Scarff-Bloom-Richardson Grade I, 91% were estrogen receptor (ER)-positive, 5% overexpressed/amplified HER2, and 5% were triple negative (TNBC). Adjuvant treatments were radiotherapy (95%), hormone therapy (82%), chemotherapy (7%), and trastuzumab (3.5%). In patients with TNBC and HER2-positive BC, chemotherapy and trastuzumab (if needed) were administered in 45% and 68%, respectively. After 5 years of follow-up, 7 patients had contralateral BC, 7 had locoregional recurrence, and 1 had distant metastasis. At 5 years, overall survival, disease-free survival, and recurrence-free survival were: 98.4% (96.9%-99.1%), 94.7% (92.4%-96.3%), and 97.1% (95.2%-98.2%), respectively.

CONCLUSION

This prospective cohort study showed that in France, the routine practice in pT1a-b pN0 breast cancers follows international standard guidelines for practice including conservative surgery followed by radiotherapy and endocrine therapy for ER-positive patients. Adjuvant chemotherapy with or without trastuzumab was used but their benefit in breast cancer of ≤10 mm remains controversial.

The effect of trastuzumab-based chemotherapy in small node-negative HER2-positive breast cancer

The prognosis of patients with stage II-III Human Epidermal growth factor Receptor 2 (HER2)-positive breast cancer has significantly improved since the addition of trastuzumab to (neo-)adjuvant chemotherapy. Several reports have shown that small (≤2 cm), node-negative, HER2-positive tumors have a relatively poor prognosis and these patients increasingly receive trastuzumab-based chemotherapy. We aimed to provide evidence for this approach in a population-based cohort. All T1N0M0 HER2-positive breast cancer patients diagnosed between 2006 and 2012 were identified from the Netherlands Cancer Registry. Patient, tumor, and treatment characteristics were recorded. Kaplan-Meier statistics were used for overall survival (OS) and breast cancer-specific survival (BCSS) estimations overall and in T1a, T1b, and T1c tumors separately. Cox regression analyses were performed to account for imbalances in baseline characteristics between treated and untreated patients. A total of 3512 patients were identified: 385 with T1a, 800 with T1b, and 2327 with T1c tumors. Forty-five percent of patients received chemotherapy and/or trastuzumab: 92 % received both. Chemotherapy and/or trastuzumab significantly improved 8-year OS (95 vs. 84 %; hazard ratio [HR] 0.29; 95 % confidence interval [CI] 0.21-0.41, P < 0.001). The effect remained significant in multivariable analyses (HR 0.35; 95 % CI 0.23-0.52, P < 0.001). BCSS was also improved with systemic treatment in univariable (96 vs. 92 %; HR 0.41; 95 % CI 0.27-0.63, P < 0.001) and multivariable analyses (HR 0.31; 95 % CI 0.19-0.53, P < 0.001). Treatment effect on OS and BCSS was similar in T1a, T1b, and T1c tumors. Chemotherapy and/or trastuzumab improves OS and BCSS and can be considered in all patients with small node-negative HER2-positive breast cancer.

Targeted therapies with companion diagnostics in the management of breast cancer: current perspectives

Breast cancer is a multifaceted disease exhibiting both intertumoral and intratumoral heterogeneity as well as variable disease course. Over 2 decades of research has advanced the understanding of the molecular substructure of breast cancer, directing the development of new therapeutic strategies against these actionable targets. In vitro diagnostics, and specifically companion diagnostics, have been integral in the successful development and implementation of these targeted therapies, such as those directed against the human epidermal growth factor receptor 2. Lately, there has been a surge in the development, commercialization, and marketing of diagnostic assays to assist in breast cancer patient care. More recently, multigene signature assays, such as Oncotype DX, MammaPrint, and Prosigna, have been integrated in the clinical setting in order to tailor decisions on adjuvant endocrine and chemotherapy treatment. This review provides an overview of the current state of breast cancer management and the use of companion diagnostics to direct personalized approaches in the treatment of breast cancer.

[Perception of pT1a,b pN0 breast tumor prognosis by the French oncology community: Results of the EURISTIC national survey]

The prognosis of infracentimetric breast cancers (BC) is heterogeneous. The EURISTIC survey describes how French oncology specialists perceive the prognosis of pT1a,b pN0 BCs. A self-administered questionnaire has been sent to over 2000 French BC specialists. Six hundred and sixty-three physicians responded. Fifty-eight percent do not consider tumor size as a key prognostic criterion. They consider that the cutoff for poor prognosis is 22mm, 10mm and 7mm for hormone receptors (HRs)+, HER2+ and triple-negative (TN) tumors respectively. Eighty-three percent of respondents consider that a HR+ pT1a,b tumor has a good prognosis (21% and 8% for HER2+ and TN respectively). Factors perceived as most detrimental are: HER2 overexpression (29% of respondents); HR- (20%); high grade (20%); TN status (14%); high KI67 (5%); presence of lymphovascular invasion (3%); young age (2%) and high mitotic index (1%). For French specialists, immunohistochemical characteristics, in particular hormone and HER2 status, are strong prognostic factors in BCs below 1cm.

The Promher Study: An Observational Italian Study on Adjuvant Therapy for HER2-Positive, pT1a-b pN0 Breast Cancer

Background

The management of pT1a-b pN0 HER2-positive breast cancer is controversial and no data about the efficacy of trastuzumab in this setting are available from randomized clinical trials. The aims of this retrospective study were to assess how patients are managed in clinical practice in Italy, which clinical or biological characteristics influenced the choice of adjuvant systemic therapy and the outcome of patients.

Methods

Data of consecutive patients who underwent surgery from January 2007 to December 2012 for HER2-positive, pT1a-b pN0 M0 breast cancer were retrospectively collected from 28 Italian centres. Analysis of contingency tables and multivariate generalized logit models were used to investigate the association between the baseline clinical and biological features and the treatment strategy adopted.

Results

Among 303 enrolled patients, 204 received adjuvant systemic therapy with trastuzumab, 65 adjuvant systemic therapy without trastuzumab and 34 did not receive adjuvant systemic therapy. At the multivariate analysis age, tumor size, proliferation index and hormone receptor status were significantly associated with the treatment choice. Five-year disease-free survival (DFS) probability was 95%, 94.3% and 69.6% for patients treated with adjuvant systemic therapy and trastuzumab, with adjuvant systemic therapy without trastuzumab and for patients who did not receive adjuvant systemic therapy, respectively (p<0.001).

Conclusions

The majority of patients (66%) with pT1a-b pN0 HER2-positive breast cancer enrolled in this retrospective study received adjuvant systemic therapy with trastuzumab, whereas only 11% patients did not receive any adjuvant systemic therapy. The choice of treatment type seems to be mainly influenced by tumor size, proliferation index, hormone receptor status and age. The 5-year DFS probability was significantly higher for patients receiving adjuvant systemic therapy with trastuzumab compared with patients not receiving adjuvant systemic therapy or receiving adjuvant systemic therapy without trastuzumab.

Updates on the treatment of human epidermal growth factor receptor type 2-positive breast cancer

PURPOSE OF REVIEW

To review the most recent developments in the treatment of human epidermal growth factor receptor type 2 (HER2)-positive breast cancer with novel HER2-targeting agents and combinations that have significantly improved clinical outcomes.

RECENT FINDINGS

Since the approval of trastuzumab 15 years ago, the natural history of HER2-positive breast cancer has been altered with improvements in survival for both early and advanced disease with the addition of this agent to standard chemotherapy. The HER2 receptor pathway drives breast cancer growth and aggressiveness, and HER2-targeted agents can improve survival in early and advanced disease. In the advanced setting, two new drugs have been approved since 2012, pertuzumab and ado-trastuzumab emtansine (T-DM1), both of which improve survival without any reciprocal increase in toxicity. However, resistance almost always ensues, pointing to the need to understand the driving mechanisms and to biomarkers that will help individualize therapy and point to newer signal transduction and other modulators.

SUMMARY

HER2-positive breast cancer represents a distinct subtype with more aggressive clinical characteristics. HER2-targeted therapies, usually in combination with chemotherapy, are the standard of care, improving the cure rate in early-stage breast cancer and lengthening survival in the advanced setting.

Precision medicine and personalized breast cancer: combination pertuzumab therapy

Trastuzumab (Herceptin), a monoclonal antibody directed against the human epidermal growth-factor receptor 2 (HER2), is the poster child for antibody-based targeted therapy in breast cancer. Pertuzumab, another humanized monoclonal antibody, binds to a different domain of HER2 and prevents the formation of HER2:HER3 dimers, which is the most potent heterodimer in the HER family. The combination of trastuzumab and pertuzumab has synergistic activity, and is associated with improved clinical outcomes. The US Food and Drug Administration (FDA) approved pertuzumab in combination with trastuzumab-based chemotherapy originally as first-line therapy for metastatic HER2-positive breast cancer in 2012, and more recently as neoadjuvant therapy for localized disease in 2013. Pertuzumab is the first neoadjuvant drug to receive accelerated approval by the FDA based on pathological complete response as the primary end point. In this article, we review the mechanism of action, pharmacokinetics, clinical efficacy, safety, and current role of pertuzumab in the management of breast cancer, as well as ongoing clinical trials and future directions regarding the utility of pertuzumab as a personalized therapeutic option for HER2-positive breast cancer. In the coming years, we anticipate increased utilization of neoadjuvant trials for drug development, biomarker discovery, and validation, and envision conduct of personalized breast cancer clinics in which therapies will be routinely selected based on genetic alterations in the tumor. Regardless of the targeted therapy combinations employed based on tumor genomic profile, trastuzumab and pertuzumab will likely continue to form the backbone of the personalized regimen for HER2-positive breast cancer.

Clinical significance of HER2-positive and triple-negative status in small (≤ 1 cm) node-negative breast cancer

BACKGROUND

Data regarding the clinical significance of HER2(+) and TN status in patients with small node-negative tumors are limited and conflicting. It remains unclear who, among those with small lesions, might benefit from more aggressive adjuvant therapy.

PATIENTS AND METHODS

We identified all node-negative breast cancer patients with tumor size ≤ 1 cm diagnosed between January 1, 1995 and December 31, 2008 using our institutional breast service database. Patients were classified according to their receptor status into 3 groups: (1) hormone receptor (HR)-positive (estrogen receptor [ER]- or progesterone receptor [PR]-positive, HER2(-)); (2) HER2(+) (immunohistochemistry 3(+) or fluorescence in situ hybridization amplification ≥ 2); and (3) TN (ER(-), PR(-), and HER2(-)). RFS was calculated using Kaplan-Meier methods.

RESULTS

Among 656 patients with tumors ≤ 1 cm, 494 (75%) of the patients were HR(+), 107 (16%) were HER2(+), and 55 (9%) were TN. Median age was 59 years (range, 27-92 years). Median follow-up was 3.5 years. The 5-year RFS rates were 98.2%, 97.1%, and 83.5% in patients with HR(+), HER2(+), and TN tumors, respectively (P < .001). In multivariate analysis, TN status was associated with worse RFS (hazard ratio, 6.70; 95% confidence interval [CI], 3.02-14.86), and HER2(+) was not (hazard ratio, 1.64; 95% CI, 0.73-3.69).

CONCLUSION

TN, but not HER2(+) status, was associated with worse RFS in patients with T1abN0 tumors, and adjuvant chemotherapy might be considered in patients with TN breast cancer.

Characteristics and clinical outcome of T1 breast cancer: a multicenter retrospective cohort study

BACKGROUND

A subgroup of T1N0M0 breast cancer (BC) carries a high potential of relapse, and thus may require adjuvant systemic therapy (AST).

PATIENTS AND METHODS

Retrospective analysis of all patients with T1 BC, who underwent surgery from January 1999 to December 2009 at 13 French sites. AST was not standardized.

RESULTS

Among 8100 women operated, 5423 had T1 tumors (708 T1a, 2208 T1b and 2508 T1c 11-15 mm). T1a differed significantly from T1b tumors with respect to several parameters (lower age, more frequent negative hormonal status and positive HER2 status, less frequent lymphovascular invasion), exhibiting a mix of favorable and poor prognosis factors. Overall survival was not different between T1a, b or c tumors but recurrence-free survival was significantly higher in T1b than in T1a tumors (P = 0.001). In multivariate analysis, tumor grade, hormone therapy and lymphovascular invasion were independent prognostic factors.

CONCLUSION

Relatively poor outcome of patients with T1a tumors might be explained by a high frequency of risk factors in this subgroup (frequent negative hormone receptors and HER2 overexpression) and by a less frequent administration of AST (endocrine treatment and chemotherapy). Tumor size might not be the main determinant of prognosis in T1 BC.

For or against adjuvant trastuzumab for pT1a-bN0M0 breast cancer patients with HER2-positive tumors: a meta-analysis of published literatures

BACKGROUND

Although the prognosis of patients with small (≤1cm) tumors is generally favorable, emerging data suggests that biological behavior varies between intrinsic subtypes in such patients. Furthermore, it still remains unclear whether HER2-positive pT1a-bN0M0 patients could benefit from adjuvant trastuzumab. For further evaluation, we sought to conduct a meta-analysis so as to get a better understanding of the prognosis for HER2-positive pT1a-bN0M0 patients and their survival benefit from adjuvant trastuzumab, accordingly, offering the implications for current practice.

METHODS

The PubMed database, the online proceedings of the American Society of Clinical Oncology (ASCO) Annual Meetings, the online proceedings of the San Antonio Breast Cancer Symposium, and the CD proceedings of the International St. Gallen Breast Cancer Conference were searched for all relevant studies published before September 2012. Relative risks (RRs) were used to compare the prognosis of different intrinsic subtypes for pT1a-bN0M0 breast cancer. Analyses were also performed to estimate the association between adjuvant trastuzumab and various survival outcomes.

RESULTS

With eight eligible studies identified, this meta-analysis demonstrated a deleterious effect of HER2+ phenotype on disease-free survival (DFS; RR = 3.677, 95% CI 2.606-5.189, p <0.001) and distant disease-free survival (DDFS; RR = 3.824, 95% CI 2.249-6.501, p<0.001) as compared to HR+/HER2- subgroup. However, significant difference failed to be achieved in terms of any endpoint between HER2+ and triple negative breast cancer (TNBC). Besides, a marked improvement in DFS was observed with the addition of trastuzumab for HER2-positive pT1a-bN0M0 patients (RR = 0.323, 95% CI 0.191-0.547, p<0.001).

CONCLUSION

This meta-analysis clarifies that intrinsic subtypes might be a reliable marker to predict the prognosis in pT1a-bN0M0 breast cancer. Besides, even for such early stage HER2-positive patients, adjuvant trastuzumab might bring significant survival benefit.