A risk stratification by hormonal receptors (ER, PgR) and HER-2 status in small (< or = 1 cm) invasive breast cancer: who might be possible candidates for adjuvant treatment?

Adjuvant early breast cancer systemic therapies according to daily used technologies

Prognosis of early breast cancer patients is significantly improved with the use of adjuvant therapies. Various guidelines have been proposed to select patients who will derive the most benefit from such treatments. However, classifications have limited usefulness in subsets of patients such as those with node negative breast cancer. The 2007 St. Paul de Vence Clinical Practice Recommendations proposed to consider adjuvant therapy in accordance with the 10-year relapse-free survival reduction estimated by Adjuvant! Online. However, many limitations remain regarding the use of Adjuvant! Online. Among them, adverse prognostic and/or predictive factors such as vascular invasion, mitotic activity, progesterone receptor negativity, and HER-2 expression are not incorporated in the routine clinical decision process. Our group has therefore issued guidelines based on the consideration of both Adjuvant! Online calculations and the prognostic and/or predictive effects of these markers. In addition, web-accessible comprehensive tables summarizing these recommendations are provided.

Chemotherapy with or without trastuzumab

The prognosis of pT1N0M0/stage I breast cancer has generally been considered so favourable that these patients are not routinely offered adjuvant systemic therapy. However, biological heterogeneity within pT1N0M0 dictates diverse outcomes within the subgroup. HER2 gene amplification or protein overexpression is uncommon in pT1N0M0 disease, but, when present, is clearly associated with a higher risk of recurrence. The role of anti-HER2 therapy in these patients is controversial. Few women with node-negative, small tumours were included in the adjuvant trastuzumab trials. There are no robust data on trastuzumab in this patient subset, although subgroup analyses suggest that proportional benefits are independent of T and N. With current guidelines and scheduling, committing to adjuvant trastuzumab involves concurrent chemotherapy, 1 year of treatment and potential cardiotoxicity. A further challenge with anti-HER2 therapy is the potential benefit in patients with demonstrable HER2 positivity within a predominantly HER2-negative tumour. The decision for therapy requires a yes/no answer, but HER2 status derives from a continuum of gene copy number and protein expression. The diagnostic threshold is made more complex by heterogeneity of the HER2 status within a tumour. This review focuses on available data for HER2-positive pT1N0M0 disease and explores the significance of intratumoural HER2 heterogeneity.

Age and survival estimates in patients who have node-negative T1ab breast cancer by breast cancer subtype

AIM

This article evaluates the risk of recurrence for patients who have small node-negative breast cancer by age and tumor subtype.

METHODS

One thousand twelve patients with a T1a,bN0 breast cancer diagnosed between 1990 and 2002 who did not receive chemotherapy or trastuzumab were included. Patients and tumor characteristics were compared using the χ(2) or Wilcoxon's rank sum tests. Survival outcomes were estimated with the Kaplan-Meier method and compared using the log-rank statistic. Cox proportional hazards models were used to determine association of breast cancer subtypes and age at diagnosis with other covariates.

RESULTS

Median age was 51.5 years. There were 771 hormone receptor (HR)-positive, 98 HER2-positive, and 143 triple-negative breast cancers (TNBC). Six hundred ninety-three patients were > 50 years, and 33 patients were ≤ 35 years. For 5-year survival estimates, there were 118 deaths and overall survival was 94.6% (95% confidence interval [CI] = 93.2%, 96.1%). After adjusting for breast cancer subtype and other tumor characteristics, patients ≤ 35 had 2.51 (95% CI = 1.21-5.22) times greater risk of worse recurrence-free survival (RFS), and 2.60 (95% CI = 1.05-6.46) times greater risk of worse distant RFS (DRFS) compared to patients > 50 years old. Compared to patients with HR-positive disease, patients with HER2-positive breast cancer had 4.98 (95% CI = 2.91-8.53) times the risk of worse RFS and 4.70 (95% CI = 2.51-8.79) times greater risk of worse DRFS, and patients with TNBC had 2.71 (95% CI = 1.59-4.59) times greater risk of worse RFS and 2.08 (95% CI = 1.04-4.17) times greater risk of worse DRFS.

CONCLUSIONS

In this cohort, patients with T1a,bN0 breast cancer, young age and breast cancer subtype were significantly associated with RFS and DRFS.

Coping with uncertainty: T1a,bN0M0 HER2-positive breast cancer, do we have a treatment threshold?

BACKGROUND

Recent retrospective studies have suggested that patients with T1a,bN0M0 human epidermal growth factor receptor 2 (HER2)-positive breast cancer are at a higher risk for recurrence and might benefit from adjuvant trastuzumab. The absolute benefits associated with treating this subgroup are uncertain.

DESIGN

We reviewed recent studies examining the prognostic value of HER2 in patients with node-negative T1a,b HER2-positive breast cancer. We calculated the number needed to treat (NNT) using baseline risk estimates for untreated T1a,bN0M0 breast cancer and the number needed to harm (NNH) using the incidence of cardiac events in each of the adjuvant trastuzumab clinical trials.

RESULTS

Several studies were identified, each with limitations inherent to retrospective database analyses: small cohort sizes, lack of systematic HER2 testing in older specimens, variations in the use of adjuvant therapy and definitions of study end points, and lack of information relating to comorbidities. The 5-year disease-free survival in the pre-trastuzumab era ranged from 77% to 95%. Comparisons between small HER2 -positive and small HER2 -negative cancers showed numerically worse outcome for the HER2-positive cohort in some but not all studies. In many instances, the NNH was larger (26-250) than the NNT (13-35); however, in a subset of patients, the NNH was lower (6) than the NNT (13-35).

CONCLUSIONS

Better prediction tools to estimate more precisely the risk for death due to comorbid illness versus breast cancer are needed. In some patients, the risks of therapy could outweigh the benefits. Treatment selection for T1a,bN0 HER2-positive cancers remains in the transition area between evidence- and subjective judgment-based medicine.

Prognostic significance of triple negative breast cancer at tumor size 1 cm and smaller

AIMS

The purpose of this study was to clarify the prognostic significance of triple-negative breast cancer (TNBC) with a tumor size ≤ 1 cm.

MATERIALS AND METHODS

Patients with primary operable breast cancer with a tumor size ≤ 1 cm were enrolled at Changhua Christian Hospital and National Cheng-Kung University Hospital. Tumors negative for ER, PR, and HER-2 were classified as TNBCs and compared with tumors with any receptor positivity (non-TNBC) for disease-free survival (DFS) and cancer-specific survival (CSS).

RESULTS

From 1995 to 2006, a total of 377 patients with tumor size ≤ 1 cm were enrolled. Compared with non-TNBC patients, TNBC patients with a tumor size ≤ 1 cm as a whole or in a lymph node-positive subgroup were not associated with a poorer 5-year DFS and CSS. In lymph node-negative patients (pT1a-bN0M0), TNBC was associated with a poorer 5-year CSS but not DFS. Compared with the hormone receptor-positive, HER-2-negative subgroup, TNBC was associated with poorer DFS and CSS. In the multivariate Cox regression hazard analysis, lymph node invasion was the most important cause of disease recurrence and cancer-specific death.

CONCLUSION

TNBC is very likely an independent risk factor in small (≤1 cm) node-negative invasive breast cancer. With tumors 1 cm and smaller, lymph node invasion was the single most important prognostic factor.

Small HER2-positive, node-negative breast cancer: who should receive systemic adjuvant treatment?

Adjuvant treatment of early-stage breast cancer with combined trastuzumab and chemotherapy has become standard in patients with HER2-positive tumors and a diameter of >1 cm or positive lymph nodes. Currently, there are no data directly supporting the use of adjuvant treatment, including trastuzumab, in patients with HER2-positive tumors, a diameter of ≤1 cm and no nodal involvement (pT1a,bpN0M0). However, 6%-10% of these small tumors are HER2 positive, and there is good evidence for an inferior clinical outcome in these patients, with recurrence rates of up to 30% after 5-10 years. Assumed that the relative risk reduction is similar to larger tumors, the absolute benefit should be large enough to consider adjuvant treatment. This review addresses current data regarding the prognosis of small HER2-positive tumors and discusses potential factors to individualize adjuvant treatment in patients with small HER2-positive tumors.

Targeted Therapy for Early and Locally Advanced Breast Cancer

The treatment of patients with breast cancer continues to evolve, with cytotoxic chemotherapy, endocrine therapy, and molecular targeted therapies representing the backbones of modern systemic breast cancer treatment. As we learn better to understand the biology of breast cancer cells, therapies to target specific pathways continue to be developed with the goal of expanding available effective therapy in specific populations. Several targeted drugs with different molecular pathways have achieved approval for metastatic breast cancer, but for early breast cancer trastuzumab is the only one that is currently approved in combination with chemotherapy for adjuvant or neoadjuvant treatment in women with HER2-positive breast cancer. Lapatinib and bevacizumab are both approved for the treatment of metastatic breast cancer and are now investigated in phase III clinical trials testing their effectiveness in the treatment of early breast cancer. In this publication, we review the current status in the treatment of early and locally advanced breast cancer with molecular targeted therapies that are currently approved or in advanced clinical development.