Prognostic and predictive values of EGFR overexpression and EGFR copy number alteration in HER2-positive breast cancer

Background:

Epidermal growth factor receptor (EGFR) is overexpressed in a subset of human epidermal growth factor receptor 2 (HER2)-positive breast cancers, and coexpression of HER2 and EGFR has been reported to be associated with poor clinical outcome. Moreover, interaction between HER2 and EGFR has been suggested to be a possible basis for trastuzumab resistance.

Methods:

We analysed the clinical significance of EGFR overexpression and EGFR gene copy number alterations in 242 HER2-positive primary breast cancers. In addition, we examined the correlations between EGFR overexpression, trastuzumab response and clinical outcome in 447 primary, and 112 metastatic HER2-positive breast cancer patients treated by trastuzumab.

Results:

Of the 242 primary cases, the level of EGFR overexpression was 2+ in 12.7% and 3+ in 11.8%. High EGFR gene copy number was detected in 10.3%. Epidermal growth factor receptor overexpression was associated with hormone receptor negativity and high Ki-67 proliferation index. In survival analyses, EGFR overexpression, but not high EGFR copy number, was associated with poor disease-free survival in all patients, and in the subgroup not receiving adjuvant trastuzumab. In 447 HER2-positive primary breast cancer patients treated with adjuvant trastuzumab, EGFR overexpression was also an independent poor prognostic factor. However, EGFR overexpression was not associated with trastuzumab response, progression-free survival or overall survival in the metastatic setting.

Conclusions:

Epidermal growth factor receptor overexpression, but not high EGFR copy number, is a poor prognostic factor in HER2-positive primary breast cancer. Epidermal growth factor receptor overexpression is a predictive factor for trastuzumab response in HER2-positive primary breast cancer, but not in metastatic breast cancer.     

Positive Expression of Insulin-Like Growth Factor-1 Receptor Is Associated with a Positive Hormone Receptor Status and a Favorable Prognosis in Breast Cancer

Purpose

Insulin-like growth factor 1 receptor (IGF-1R) is commonly expressed in primary breast cancers. Understanding the role of IGF-1R signaling in the different subtypes of breast cancer is important because each subtype has a different outcome and requires different treatment modalities. However, the precise biological significance of IGF-1R expression in cancer cells is still unclear. In this study, we examined the expression of IGF-1R in the different molecular subtypes of breast cancer. The effects of IGF-1R expression on the survival rates and outcomes of breast cancer were also examined.

Methods

IGF-1R expression was evaluated immunohistochemically in tissue microarray blocks constructed from 1,198 invasive breast cancer samples collected from six medical institutions. IGF-1R expression was interpreted according to the human epidermal growth factor receptor 2 (HER2)/neu immunohistochemistry scoring system. Scores of 2+ and 3+ were considered positive.

Results

Positive IGF-1R expression was observed in 65.4% of invasive breast cancer samples. IGF-1R expression was detected in all cancer subtypes (luminal A, 84.4%; luminal B, 75.9%; HER2, 21.2%; triple-negative, 46.6%) and was found to be associated with a positive hormone receptor status and the absence of HER2 amplification (p<0.001). Positive IGF-1R expression was significantly associated with high survival rates (p=0.014). However, a multivariate analysis revealed that the expression levels of IGF-1R did not achieve statistical significance. In the triple-negative cancer subtype, IGF-1R expression was found to be associated with a lower disease-free survival rate (p=0.031).

Conclusion

Positive IGF-1R expression is associated with a favorable prognosis in breast cancer. IGF-1R is frequently expressed in the luminal A/B subtypes of breast cancer, and its expression is related to the hormone receptor status.     

Patterns of Recurrence after Breast-Conserving Treatment for Early Stage Breast Cancer by Molecular Subtype

Purpose

To study clinical features and patterns of recurrence after breast-conserving treatment (BCT) for three molecular subtypes of early stage breast cancer.

Methods

The sample studied included 596 patients with T1-2N0-1 breast cancer who received BCT. Three groups were defined by receptor status. Luminal: estrogen receptor (ER) or progesterone receptor (PR) positive; triple negative (TN): ER, PR, and epidermal growth factor receptor-2 (HER2) receptor negative; and HER2 overexpressing: ER and PR negative but HER2 receptor positive.

Results

The number of patients in each group was 408 (68.5%), 105 (17.6%), and 83 (13.9%), respectively. The median follow-up period was 79 months. The TN and HER2 subtypes occurred in younger patients (p=0.0007) and had higher nuclear grade and poorer histologic grade (p<0.0001 and 0.0071, respectively). During the follow-up period, locoregional recurrence was detected as the first site of recurrence in 26 (6.4%), 11 (10.5%), and 9 (10.8%) patients in the luminal, TN, and HER2 subtypes, respectively (p=0.1924). Thirty-one (7.6%), 7 (6.7%), and 7 (8.4%) patients in each group had distant metastases as the first sign of recurrence (p=0.8996). Median time to locoregional and distant recurrence was shorter in the HER2 subtype (p=0.0889 and 0.0780, respectively), and the HER2 subtype was significantly associated with poor overall survival (p=0.0009).

Conclusion

After BCT in Korean women with early stage breast cancer, the patterns of recurrence were not different among the molecular subtypes, although the TN and HER2 subtypes were associated with younger age, higher nuclear grade, and poorer histologic grade.     

Evaluation of HER2 and p53 expression in predicting response to docetaxel-based first-line chemotherapy in advanced breast cancer

Background

The human epidermal growth factor receptor 2 (HER2) and p53 pathways may be involved in chemotherapy sensitivity and/or resistance. We explore the value of HER2 and p53 status to foretell docetaxel sensitivity in advanced breast cancer.

Methods

HER2 and p53 expression was analysed in 36 (median age 55 yrs; range 37-87) metastatic breast cancer patients receiving docetaxel-based first-line chemotherapy. HER2 was determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), p53 was tested by IHC. We correlate the expression of study parameters with pathologic parameters, RECIST response and survival. The standard cut-off value of 2 was used to determine HER2 overexpression while p53 mean expression level was used to divide low/high expressors tumors.

Results

Median time to progression and overall survival were 9 (range 2 - 54) and 20 (range 3 - 101) months. Overall response rate was 41.6%. Nine cases showed HER2 overexpression. HER2 was more frequently overexpressed in less differentiated (p = 0.05) and higher stage (p = 0.003) disease. Mean FISH-HER2 values were significantly higher in responder than in non-responder pts (8.53 ± 10.21 vs 2.50 ± 4.12, p = 0.027). Moreover, HER2 overexpression correlates with treatment response at cross-tabulation analysis (p = 0.046). p53 expression was only associated with higher stage disease (p = 0.02) but lack of any significant association with HER status or docetaxel response. No significant relation with survival was observed for any parameter.

Conclusion

Our data seem to indicate that FISH-determined HER2 status but not p53 is associated with docetaxel sensitivity in metastatic breast cancer.     

Metformin increases survival in hormone receptor-positive,HER2-positive breast cancer patients with diabetes

Introduction

Metformin use has recently been observed to decrease both the rate and mortality of breast cancer. Our study was aim to determine whether metformin use is associated with survival in diabetic breast cancer patients by breast cancer subtype and systemic treatment.

Methods

Data from the Asan Medical Center Breast Cancer Database from 1997 to 2007 were analyzed. The study cohort comprised 6,967 nondiabetic patients, 202 diabetic patients treated with metformin, and 184 diabetic patients that did not receive metformin. Patients who were divided into three groups by diabetes status and metformin use were also divided into four subgroups by hormone receptor and HER2-neu status.

Results

In Kaplan-Meier analysis, the metformin group had a significantly better overall and cancer specific survival outcome compared with non metformin diabetic group (P <0.005 for both). There was no difference in survival between the nondiabetic and metformin groups. In multivariate analysis, Compared with metformin group, patients who did not receive metformin tended to have a higher risk of metastasis with HR 5.37 (95 % CI, 1.88 to 15.28) and breast cancer death with HR 6.51 (95 % CI, 1.88 to 15.28) on the hormone receptor-positive and HER2-negative breast cancer. The significant survival benefit of metformin observed in diabetic patients who received chemotherapy and endocrine therapy (HR for disease free survival 2.14; 95 % CI 1.14 to 4.04) was not seen in diabetic patients who did not receive these treatments.

Conclusion

Patients receiving metformin treatment when breast cancer diagnosis show a better prognosis only if they have hormone receptor-positive, HER2-positive tumors. Metformin treatment might provide a survival benefit when added to systemic therapy in diabetic patients.     

Cytogenetic analysis of HER1/EGFR, HER2, HER3 and HER4 in 278 breast cancer patients

Introduction

The HER (human EGFR related) family of receptor tyrosine kinases (HER1/EGFR (epidermal growth factor receptor)/c-erbB1, HER2/c-erbB2, HER3/c-erbB3 and HER4/c-erbB4) shares a high degree of structural and functional homology. It constitutes a complex network, coupling various extracellular ligands to intracellular signal transduction pathways resulting in receptor interaction and cross-activation. The most famous family member is HER2, which is a target in Herceptin™ therapy in metastatic status and also in adjuvant therapy of breast cancer in the event of dysregulation as a result of gene amplification and resulting protein overexpression. The HER2-related HER receptors have been shown to interact directly with HER2 receptors and thereby mutually affect their activity and subsequent malignant growth potential. However, the clinical outcome with regard to total HER receptor state remains largely unknown.

Methods

We investigated HER1–HER4, at both the DNA and the protein level, using fluorescence in situ hybridisation (FISH) probes targeted to all four receptor loci and also immunohistochemistry in tissue microarrays derived from 278 breast cancer patients.

Results

We retrospectively found HER3 gene amplification with a univariate negative impact on disease-free survival (hazard ratio 2.35, 95% confidence interval 1.08 to 5.11, p = 0.031), whereas HER4 amplification showed a positive trend in overall and disease-free survival. Protein expression revealed no additional information.

Conclusion

Overall, the simultaneous quantification of HER3 and HER4 receptor genes by means of FISH might enable the rendering of a more precise stratification of breast cancer patients by providing additional prognostic information. The continuation of explorative and prospective studies on all HER receptors will be required for an evaluation of their potential use for specific therapeutic targeting with respect to individualised therapy.     

Glomeruloid microvascular proliferation is associated with lack of response to chemotherapy in breast cancer

Background:

Glomeruloid microvascular proliferation (GMP), a novel histology-based angiogenesis marker, has been associated with decreased survival in several human cancers.

Methods:

In this study, we evaluated the ability of GMP to predict clinical response to neoadjuvant chemotherapy in a series of locally advanced breast cancers (n=112).

Results:

Presence of GMP (21% of the cases) was significantly associated with high-grade tumours and TP53 mutations in addition to the basal-like and HER2 subtypes of breast cancer as defined by gene expression data. GMP was correlated to a gene expression signature for tumour hypoxia response. The GMP pattern was also significantly associated with lack of treatment response and progressive disease (P=0.004).

Interpretation:

The findings suggest that GMP might be able to predict the lack of response to neoadjuvant chemotherapy in locally advanced breast cancer. Whether GMP may be an independent predictor compared with other factors including TP53 mutation status and tumour grade needs confirmation in larger studies.     

HER2/neu testing in primary colorectal carcinoma

Background:

Anti-HER2/neu therapy is well-established in breast and gastric carcinoma. The increased understanding of this pathway led to the identification of new promising drugs in addition to trastuzumab, offering further perspectives. The role of HER2/neu in colorectal carcinoma is controversially discussed, as discrepant data has been reported.

Methods:

Here, we retrospectively assessed the prevalence of HER2/neu positivity in a large series of colorectal carcinoma, testing HER2/neu status according to current recommendations. We correlated the results to clinico-pathological data and patient survival.

Results:

Overall, in 1645 primary colorectal carcinoma cases, 1.6% of the cases were HER2/neu positive. HER2/neu positivity significantly correlated with higher UICC stages (P=0.017) and lymph node metastases (P=0.029). In the subgroup of sigmoideal and rectal carcinomas, positive HER2/neu status was associated with T-category (P=0.041) and higher UICC stages (P=0.022). Although statistically not significant, HER2/neu-positive colorectal carcinomas displayed a tendency to poorer overall survival.

Conclusions:

These results illustrate the importance of testing HER2/neu by approved diagnostic techniques and scoring systems. We assume that although the prevalence of HER2/neu positivity in colorectal carcinoma is low, HER2/neu testing in advanced, nodal-positive colorectal carcinoma is reasonable, offering a potential target in high risk colorectal carcinoma.     

Increased mortality in HER2 positive, oestrogen receptor positive invasive breast cancer: a population-based study

Background:

This study assessed the impact of human epidermal growth factor receptor 2 (HER2) status on the outcomes in an unselected population of breast cancer patients who did not receive HER2-targeted therapy.

Methods:

HER2 status by immunohistochemistry and fluorescence in situ hybridisation was compared with clinicopathological data, overall survival (OS) and disease-free survival (DFS) for all patients presenting with breast cancer over 3 years.

Results:

In 865 patients (median follow up 6.02 years), HER2 positivity was identified in 13.3% of all cancers and was associated with higher tumour grade (P<10⁻⁸), lymphovascular invasion (P<0.001) and axillary nodal metastasis (P=0.003). There was a negative association with oestrogen-receptor (ER) and progesterone-receptor expression (P<10⁻⁸), but the majority (57%) of HER2+tumours were ER+HER2 positivity was associated with poorer OS (P=0.0046) and DFS (P=0.0001) confined to the lymph node-positive (LN+) and ER+ subgroups.

Conclusion:

HER2-positive cancers were less common in this population-based cohort than most selected series. The association of HER2 positivity with poor prognosis was confined to the ER+ and LN+ subgroups. The survival deficit for the 7.5% of patients with ER+/HER2+ cancer compared with ER+/HER2– patients points to a significant subgroup of women who may not (currently) be considered for HER2-directed therapy.     

Detection of HER2 amplification in circulating free DNA in patients with breast cancer

Background:

Human epidermal growth factor receptor 2 (HER2) is amplified and overexpressed in 20–25% of breast cancers. This study investigated circulating free DNA (cfDNA) for detection of HER2 gene amplification in patients with breast cancer.

Methods:

Circulating free DNA was extracted from plasma of unselected patients with primary breast cancer (22 before surgery and 68 following treatment), 30 metastatic patients and 98 female controls using the QIAamp Blood DNA Mini Kit (Qiagen). The ratio of HER2 to an unamplified reference gene (contactin-associated protein 1 (CNTNAP1)) was measured in cfDNA samples by quantitative PCR (qPCR) using SK-BR-3 cell line DNA as a positive control.

Results:

We validated the qPCR assay with DNA extracted from 23 HER2 3+ and 40 HER2-negative tumour tissue samples; the results agreed for 60 of 63 (95.2%) tumours. Amplification was detected in cfDNA for 8 of 68 patients following primary breast cancer treatment and 5 of 30 metastatic patients, but was undetected in 22 patients with primary breast cancer and 98 healthy female controls. Of the patients with amplification in cfDNA, 10 had HER2 3+ tumour status by immunohistochemistry.

Conclusions:

The results demonstrate for the first time the existence of amplified HER2 in cfDNA in the follow-up of breast cancer patients who are otherwise disease free. This approach could potentially provide a marker in patients with HER2-positive breast cancer.     

Expression of sphingosine 1-phosphate receptor 4 and sphingosine kinase 1 is associated with outcome in oestrogen receptor-negative breast cancer

Background:

We previously reported that sphingosine 1-phosphate receptor 4 (S1P₄) is expressed and stimulates the ERK-1/2 pathway via a human epidermal growth factor receptor 2 (HER2)-dependent mechanism in oestrogen receptor-negative (ER⁻) MDA-MB-453 breast cancer cells.

Methods:

Clinical relevance of S1P₄ and sphingosine kinase 1 (SK1, which catalyses the formation of S1P) was assessed in a cohort of 140 ER⁻ breast tumours by immunohistochemistry (IHC) and the weighted histoscore method. Additional evidence for a functional interaction between S1P₄ and SK1 and between HER2 and SK1 was obtained using MDA-MB-453 cells.

Results:

High S1P₄ expression is associated with shorter disease-free (P=0.014) and disease-specific survival (P=0.004), and was independent on multivariate analysis. In addition, patients with tumours that contain high and low levels of SK1 and S1P₄, respectively, have a significantly shorter disease-free survival (P=0.043) and disease-specific survival (P=0.033) compared with patients whose tumours contain both low S1P₄ and SK1 levels. In addition, high tumour expression of SK1 was significantly associated with shorter disease-specific survival (P=0.0001) in patients with HER2-positive tumours. Treatment of MDA-MB-453 cells with the SK1 inhibitor, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole) reduced the basal and S1P/S1P₄-induced activation of ERK-1/2 and altered HER2 trafficking in these cells.

Conclusion:

These findings highlight an important role for S1P₄ and SK1 in ER⁻ breast cancer progression.     

Treatment Outcome of Breast Cancer with Pathologically Proven Synchronous Ipsilateral Supraclavicular Lymph Node Metastases

Purpose

The aim of this study was to investigate the prognosis, patterns of failure, and prognostic factors for breast cancer patients with pathologically proven synchronous ipsilateral supraclavicular lymph node (ISCLN) metastases.

Methods

We reviewed the records of breast cancer patients with pathologically proven ISCLN metastases. Local aggressive treatment was defined as treatment including surgery, axillary lymph node dissection (ALND), ISCLN excision, radiotherapy (RT), and chemotherapy.

Results

A total of 111 patients were included. The 5-year overall survival (OS) and disease-free survival (DFS) rates were 64.2% and 56.2%, respectively. On univariate analysis, RT, ALND, trastuzumab treatment, hormone receptor (HR) status, and local aggressive treatment were identified as significant factors for OS. The 5-year OS for 73 patients who received local aggressive treatment was superior to that of 38 patients who received nonaggressive treatment (70.9% vs. 49.3%, p=0.036). Multivariate analysis showed that RT, HR status, and trastuzumab were significant variables for the 5-year OS and DFS.

Conclusion

Multimodality treatment with surgery, taxane-based chemotherapy, hormone therapy, and RT is strongly recommended for breast cancer patients with synchronous ISCLN metastases.     

Expression of truncated human epidermal growth factor receptor 2 on circulating tumor cells of breast cancer patients

Introduction

The truncated form of human epidermal growth factor receptor 2 (p95HER2) lacks the HER2 extracellular domain and has been associated with poor prognosis and resistance to trastuzumab. In the present study, the expression of p95HER2 was investigated on circulating tumor cells (CTCs) from breast cancer patients.

Methods

Triple-staining immunofluorescent experiments were performed on peripheral blood mononuclear cells’ (PBMCs) cytospins obtained from patients with early (n = 24) and metastatic (n = 37) breast cancer. Cells were stained with the pancytokeratin (A45-B/B3) antibody coupled with antibodies against the extracellular (ECD) and the intracellular (ICD) domains of HER2. Slides were analyzed with either confocal laser scanning microscopy or with the Ariol system.

Results

HER2-positive CTCs were identified in 55.6 % of early and 65.2 % of metastatic CTC-positive breast cancer patients. p95HER2-positive CTCs were identified in 11.1 % of early and 39.1 % of metastatic breast cancer patients (p = 0.047). In 14 patients with metastatic HER2-positive breast cancer, CTCs were also analyzed before and after first-line trastuzumab therapy. Trastuzumab reduced the percentage of patients with full-length HER2-positive CTCs from 70 % at baseline to 50 % (p = 0.035) after treatment while increased the percentage of patients with p95HER2-positive CTCs from 40 % to 63 %. Moreover, the overall survival of metastatic patients with p95HER2-positive CTCs was significantly decreased (p = 0.03).

Conclusions

p95HER2-positive CTCs can be detected in both early and metastatic breast cancer patients. Their incidence is increased in the metastatic setting and their presence is associated with poor survival. Longitudinal studies during anti-HER2 treatment are required to determine the clinical relevance of p95HER2-expressing CTCs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0624-x) contains supplementary material, which is available to authorized users.     

Impact of anti-HER2 therapy on overall survival in HER2-overexpressing breast cancer patients with brain metastases

Background:

Trastuzumab-based therapy after diagnosis of brain metastases (BM) may improve survival due to prolonged systemic disease control. We investigated whether lapatinib may yield additional survival benefit.

Methods:

Eighty patients with BM from HER2-positive breast cancer were identified. Karnofsky Performance Score (KPS) of at least 70 was required. We included a control group of 37 patients treated before 2003, when continuation of trastuzumab after diagnosis of BM was not yet recommended. Remainders received either trastuzumab or lapatinib and trastuzumab (either concomitantly or sequentially) with or without chemotherapy.

Results:

Median overall survival (OS) in patients receiving trastuzumab after diagnosis of BM was 13 months; corresponding numbers were 9 months in patients treated with chemotherapy, and 3 months with radiotherapy alone. Median OS was not reached in the lapatinib group. Addition of lapatinib prolonged OS over trastuzumab alone (P=0.002). After correction for potential confounders, lapatinib therapy remained an independent positive predictor for survival (HR 0.279; P=0.012).

Interpretation:

This retrospective single-centre study suggests that the introduction of lapatinib improved survival in patients with BM from HER2-positive breast cancer. Patients with KPS ⩾70 may benefit when treated with lapatinib in addition to trastuzumab after completion of local therapy.     

Perhexiline promotes HER3 ablation through receptor internalization and inhibits tumor growth

Introduction

Human epidermal growth factor receptor HER3 has been implicated in promoting the aggressiveness and metastatic potential of breast cancer. Upregulation of HER3 has been found to be a major mechanism underlying drug resistance to EGFR and HER2 tyrosine kinase inhibitors and to endocrine therapy in the treatment of breast cancer. Thus, agents that reduce HER3 expression at the plasma membrane may synergize with current therapies and offer a novel therapeutic strategy to improve treatment.

Methods

We devised an image-based screening platform using membrane localized HER3-YFP to identify small molecules that promote HER3 internalization and degradation. In vitro and in vivo tumor models were used to characterize the signaling effects of perhexiline, an anti-anginal drug, identified by the screening platform.

Results

We found perhexiline, an anti-anginal drug, selectively internalized HER3, decreased HER3 expression, and subsequently inhibited signaling downstream of HER3. Consistent with these results, perhexiline inhibited breast cancer cell proliferation in vitro and tumor growth in vivo.

Conclusions

This is the first demonstration that HER3 can be targeted with small molecules by eliminating it from the cell membrane. The novel approach used here led to the discovery that perhexiline ablates HER3 expression, and offers an opportunity to identify HER3 ablation modulators as innovative therapeutics to improve survival in breast cancer patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0528-9) contains supplementary material, which is available to authorized users.     

Carbonic anhydrase IX is a predictive marker of doxorubicin resistance in early-stage breast cancer independent of HER2 and TOP2A amplification

Background:

In early-stage breast cancer, adjuvant chemotherapy is associated with significant systemic toxicity with only a modest survival benefit. Therefore, there is considerable interest in identifying predictive markers of response to therapy. Doxorubicin, one of the most common drugs used to treat breast cancer, is an anthracycline chemotherapeutic agent, a class of drugs known to be affected by hypoxia. Accordingly, we examined whether expression of the endogenous hypoxia marker carbonic anhydrase IX (CA IX) is predictive of outcome in early-stage breast cancer patients treated with doxorubicin.

Methods:

We obtained 209 early-stage pre-treatment surgically-resected breast tumours from patients, who received doxorubicin in their chemotherapeutic regimen and had >10 years of follow-up. Immunohistochemistry was used to detect CA IX, and we used fluorescence in situ hybridisation to detect both human epidermal growth factor receptor (HER2) and DNA topoisomerase II-alpha (TOP2A) gene amplification.

Results:

Carbonic anhydrase IX intensity was significantly correlated with progression-free survival (PFS) and overall survival (OS) in patients receiving 300 mg m⁻² of doxorubicin (HR=1.82 and 3.77; P=0.0014 and 0.010, respectively). There was a significant, inverse correlation between CA IX score and oestrogen receptor expression, but no significant correlations were seen with either HER2 or TOP2A ratio.

Conclusion:

We demonstrate that CA IX expression is correlated with worse PFS and OS for breast cancer patients treated with doxorubicin, independent of HER2 or TOP2A gene amplification. This study provides evidence that using CA IX to detect hypoxia in surgically-resected breast tumours may be of clinical use in choosing an appropriate chemotherapy regimen.     

Lapatinib monotherapy in patients with relapsed, advanced, or metastatic breast cancer: efficacy, safety, and biomarker results from Japanese patients phase II studies

Background:

HER2-positive metastatic breast cancer (MBC) relapsing after trastuzumab-based therapy may require continued HER2 receptor inhibition to control the disease and preserve the patients'' quality-of-life. Efficacy and safety of lapatinib monotherapy was evaluated in Japanese breast cancer patients after trastuzumab-based therapies.

Methods:

In studies, EGF100642 and EGF104911 evaluated the efficacy and safety of oral lapatinib given 1500 mg once daily in patients with advanced or MBC. All patients progressed on anthracyclines and taxanes; HER2-positive patients had also progressed on trastuzumab.

Results:

For HER2-positive tumours (n=100), objective response rate was 19.0% (95% confidence interval (CI): 11.8–28.1) and clinical benefit rate (CBR) was 25.0% (95% CI: 16.9–34.7). One out of 22 HER2-negative tumour was documented as complete response (n=22). The median time-to-progression (TTP) in the HER2-positive and HER2-negative groups was 13.0 and 8.0 weeks (P=0.007); median overall survival was 58.3 and 40.0 weeks, respectively. The most frequent adverse event was diarrhoea. TTP and CBR were significantly associated with HER2 expression. Patients with tumours harbouring an H1047R PIK3CA mutation or low expression of PTEN derived clinical benefit from lapatinib.

Conclusion:

Lapatinib monotherapy had shown anti-tumour activity in Japanese patients with HER2-positive MBC that relapsed after trastuzumab-based therapy, including those with brain metastases. Patients benefiting from lapatinib may have biomarker profiles differing from that reported for trastuzumab.     

Effect Modification of Hormonal Therapy by p53 Status in Invasive Breast Cancer

Purpose

We aimed to confirm the prognostic and predictive value of p53 expression, particularly in invasive breast cancer patients, according to immunohistochemical hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status.

Methods

Immunohistochemical data for p53, estrogen receptor, progesterone receptor, and HER2 expression from a total of 15,598 patients were retrospectively retrieved from the web-based database of the Korean Breast Cancer Society. Overall survival (OS) and breast cancer-specific survival (BCSS) were calculated and compared using the Kaplan-Meier method and log-rank test, respectively. Multivariate analyses were performed using a stratified Cox proportional hazard regression model. A model evaluating interactions between p53 expression and both hormonal therapy and chemotherapy was used to determine the treatment benefit from both modalities.

Results

The prognostic value of p53 for OS and BCSS was most significant in the HR+/HER2- subgroup, with hazard ratios of 1.44 (95% confidence interval [CI], 1.08-1.93) and 1.47 (95% CI, 1.09-1.99), respectively. The p53 overexpression hazard ratios were of borderline significance for the HR+/HER2+ subgroup and were not significant for the HR-/HER2+ and HR-/HER2- subgroups. The model with interaction terms revealed that hormonal therapy significantly interacts with p53 status (p=0.002 and p=0.007 for OS and BCSS, respectively), suggesting an insignificant prognostic value for p53 status (p=0.268 and p=0.296 for OS and BCSS, respectively). An interaction between chemotherapy and p53 status was not found in this model.

Conclusion

p53 overexpression has independent prognostic value, particularly in cases of HR+/HER2- invasive breast cancer, which may be due to effect modification of hormonal therapy dependent on p53 status.     

Radiation Treatment in Pathologic N0-N1 Patients Treated with Neoadjuvant Chemotherapy Followed by Surgery for Locally Advanced Breast Cancer

Purpose

This study evaluated the treatment results and the necessity to irradiate the supraclavicular lymph node (SCN) region in pathological N0-N1 (pN0-N1) patients with locally advanced breast cancer treated with neoadjuvant chemotherapy (NAC) followed by surgery and radiotherapy (RT).

Methods

Between 1996 and 2008, 184 patients with initial tumor size >5 cm or clinically positive lymph nodes were treated with NAC followed by surgery and RT. Among these patients, we retrospectively reviewed 98 patients with pN0-N1. Mastectomy was performed in 55%. The pathological lymph node stage was N0 in 49% and N1 in 51%. All patients received adjuvant RT to chest wall or breast and 56 patients (57%) also received RT to the SCN region (SCNRT).

Results

At 5 years, locoregional recurrence (LRR)-free survival, distant metastasis-free survival, disease-free survival (DFS), and overall survival rates were 93%, 83%, 81%, and 91%, respectively. In pN0 patients, LRR was 7% in SCNRT- group and 5% in SCNRT+ group. In pN1 patients, LRR was 7% in SCNRT- group and 6% in SCNRT+ group. There was no significant difference of LRR, regardless of SCNRT. However, in pN1 patients, there were more patients with poor prognostic factors in the SCNRT+ group compared to SCNRT- group. These factors might be associated with worse DFS in the SCNRT+ group, even though RT was administered to the SCN region.

Conclusion

Our study showed the similar LRR, regardless of SCNRT in pN0-pN1 breast cancer patients after NAC followed by surgery. Prospective randomized trial is called for to validate the role of SCNRT.     

Survival Outcomes of Different Treatment Methods for the Ipsilateral Breast of Occult Breast Cancer Patients with Axillary Lymph Node Metastasis: A Single Center Experience

Purpose

This study compared the survival outcomes of different treatment methods for the ipsilateral breast of occult breast cancer (OBC) patients with axillary lymph node metastasis.

Methods

A retrospective study was conducted in which forty OBC patients with axillary lymph node metastasis were identified out of 15,029 patients who had been diagnosed with a primary breast cancer at between 1992 and 2010. The patients were categorized into three treatment groups based on ipsilateral breast management: breast-conserving surgery (BCS) (n=17), mastectomy (n=12), and nonsurgical intervention with or without radiation therapy (No surgery with or without radiation therapy [No Op±RT]) (n=11). All patients underwent axillary lymph node dissection. Cases were evaluated based on treatment and potential prognostic factors with respect to overall survival (OS) and disease-free survival (DFS).

Results

During the follow-up period (median follow-up of 71.5 months), the overall OS and DFS were 76.9% and 74.9%, respectively. The 5-year treatment-specific OS was 72.0% for the BCS group, 74.0% for the mastectomy group, and 87.5% for the No Op±RT group (log-rank p=0.49). The 5-year DFS was 70.6% for the BCS group, 66.7% for the mastectomy group, and 90.9% for the No Op±RT group (log-rank p=0.36). Recurrence rates for the BCS and No Op±RT groups were 5.9% and 18.2%, respectively. Histologic grade and lymph node status were inversely correlated with DFS (log-rank p=0.04 and p<0.01, respectively).

Conclusion

There was no difference in survival outcomes between the three treatment methods for the ipsilateral breast (mastectomy, BCS, and No Op±RT) of OBC patients with axillary lymph node metastasis. A large-scale multicenter study is needed to validate the results from this small retrospective study.