Association of PIK3CA mutation with outcomes in HER2-positive breast cancer treated with anti-HER2 therapy: A meta-analysis and bioinformatic analysis of TCGA‑BRCA data

BACKGROUND

This study aimed to comprehensively explore the clinical significance of PIK3CA mutation in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with anti-HER2 therapy.

METHODS

We systematically searched PubMed, Embase, and the Cochrane databases for eligible studies assessing the association between PIK3CA mutation and outcomes in patients with HER2-positive breast cancer receiving anti-HER2 therapy. The main outcomes included: (1) pathological complete response (pCR) or disease-free survival (DFS) for the neoadjuvant setting; (2) DFS or invasive DFS for the adjuvant setting; (3) objective response rate (ORR), progression-free survival (PFS), time-to-progression (TTP), or overall survival (OS) for the metastatic setting. The mutational landscape of HER2-positive breast cancer according to PIK3CA mutation status was examined based on TCGA breast cancer dataset.

RESULTS

Totally, 43 eligible studies, covering 11,099 patients with available data on PIK3CA mutation status, were identified. In the neoadjuvant setting, PIK3CA mutation was significantly associated with a lower pCR rate (OR=0.23, 95% CI 0.19-0.27, p<0.001). This association remained significant irrespective of the type of anti-HER2 therapy (single-agent or dual-agent) and hormone receptor status. There were no significant differences in DFS between PIK3CA mutated and wild-type patients in either the neoadjuvant or adjuvant settings. In the metastatic setting, PIK3CA mutation predicted worse ORR (OR=0.26, 95%CI 0.17-0.40, p<0.001), PFS (HR=1.28, 95%CI 1.03-1.59, p = 0.024) and TTP (HR=2.27, 95%CI 1.54-3.34, p<0.001). However, no significant association was observed between PIK3CA mutation status and OS. Distinct mutational landscapes were observed in HER2-positive breast cancer between individuals with PIK3CA mutations and those with wild-type PIK3CA.

CONCLUSIONS

PIK3CA mutation was significantly associated with a lower pCR rate in HER2-positive breast cancer treated with neoadjuvant anti-HER2 therapy. In the metastatic setting, PIK3CA mutation was predictive of worse ORR, PFS and TTP. These results suggest the potential for developing PI3K inhibitors as a therapeutic option for these patients.

Efficacy of anti-HER2 drugs in the treatment of patients with HER2-mutated cancers: a systematic review and meta-analysis

Anti-human epidermal growth factor receptor-2 (anti-HER2) therapy has shown excellent efficacy in patients with HER2 overexpression and amplification. Although HER2 mutations are rarely expressed in several cancers, when they occur, they can activate the HER2 signaling pathway. In recent years, studies have shown that anti-HER2 drugs have promising efficacy in patients with HER2 mutations. Based on keywords, we searched databases, such as PubMed, Embase, and Cochrane Library, and the main conference abstracts. We extracted data on objective response rate (ORR), clinical benefit rate (CBR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS) from studies on the efficacy of anti-HER2 therapies in patients with HER2-mutated cancers, and analyzed grade 3 or higher adverse events (AEs). We included 19 single-arm clinical studies and 3 randomized controlled trials (RCTs), containing a total of 1017 patients with HER2 mutations, involving seven drugs and nine cancers, and 18 studies enrolled a high proportion of heavily pretreated patients who had received multiple lines of therapy. Our results showed pooled ORR and CBR of 25.0% (range, 3.8-72.7%; 95% CI, 18-32%) and 36.0% (range, 8.3-63.0%; 95% CI, 31-42%) for anti-HER2 therapy in HER2-mutated cancers. The pooled median PFS, OS, DOR were 4.89 (95% CI, 4.16-5.62), 12.78 (95% CI, 10.24-15.32), and 8.12 (95% CI, 6.48-9.75) months, respectively. In a subgroup analysis, we analyzed the ORR for different cancers, showing 27.0, 25.0, 23.0, and 16.0% for breast, lung, cervical, and biliary tract cancers, respectively. ORR analyses were performed for different drugs as monotherapy or in combination, showing 60.0% for trastuzumab deruxtecan (T-DXd), 31.0% for pyrotinib, 26.0% for neratinib combined with trastuzumab, 25.0% for neratinib combined with fulvestrant, 19.0% for trastuzumab combined with pertuzumab, and 16.0% for neratinib. In addition, we found that diarrhoea, neutropenia, and thrombocytopenia were the most common grade ≥ 3 AEs associated with anti-HER2 therapeutic agents. In this meta-analysis of heavily pretreated patients with HER2 mutations, anti-HER2 therapies, DS-8201 and trastuzumab emtansine, showed promising efficacy and activity. Anti-HER2 therapies showed different efficacies in different or the same cancer settings and all had a tolerable safety profile.

SEOM-GEICAM-SOLTI clinical guidelines in advanced breast cancer (2022)

Advanced breast cancer represents a challenge for patients and for physicians due its dynamic genomic changes yielding to a resistance to treatments. The main goal is to improve quality of live and survival of the patients through the most appropriate subsequent therapies based on the knowledge of the natural history of the disease. In these guidelines, we summarize current evidence and available therapies for the medical management of advanced breast cancer.

Optimizing treatment for HER2-positive HR-positive breast cancer

Triple-positive breast tumors overexpress human epidermal growth factor receptor 2 (HER2) and are positive for hormone receptor (HR) expression. Data from real-life and clinical trials show that estrogen receptor (ER) expression affects the response to combinations of anti-HER2 and associated systemic therapies. Despite triple-positive tumors having decreased response rates compared to HR-negative/HER2-positive breast cancers, optimizing anti-HER2 treatment with dual anti-HER2 blockade remains important for optimal disease control. Preclinical data on the cross-talk between ER and growth factor receptor pathways show the efficacy of combinations of endocrine therapy and anti-HER2 drugs, which is confirmed in the clinic. Molecular dissection of triple-positive breast cancer might provide the rational for additional therapeutic strategies and the identification of promising biomarkers. This review summarizes data on systemic treatment efficacy from major clinical trials and perspectives for future clinical research in triple-positive breast cancer.

A population-based study

BACKGROUND

HER2-positive (HER2 +) invasive lobular breast cancer (ILC) is rare and poorly characterised. In particular, patient outcomes compared to those associated with HER2 + invasive ductal cancer (IDC) and HER2-negative (HER2 -) ILC, as well as the benefits of anti-HER2 therapy, are not well established.

METHODS

We analysed the data from the Côte d'Or Registry of Breast and Gynaecological Cancers (France) for all patients diagnosed with early-stage HER2 + ILC (62 cases), HER2 + IDC (833 cases) and HER2 - ILC (685 cases) between 1998 and 2015 to compare overall and disease-free survival (OS and DFS) between these groups in correlation with anti-HER2 therapy.

RESULTS

ILCs were associated with older age, larger tumours, lower histological grades, higher hormonal receptor positivity rates and multifocality, and more common endocrine therapy. OS and DFS between the three groups did not differ. We found that anti-HER2 therapy was associated with a survival benefit in patients with HER2 + IDC. In contrast, the survival of HER2 + ILC patients was not improved by anti-HER2 treatment, remaining close to that of HER2 - ILC patients.

CONCLUSION

HER2 + ILC seems not to be associated with better outcomes than HER2 + IDC but may not differ from HER2 - ILC in terms of survival.

A clinicopathological study and survival analysis of 99 breast cancers with HER2/CEP17 ratio ≥ 2.0 and an average HER2 copy number < 4.0 per cell in China

BACKGROUND

Breast cancer patients of American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP) Group 2 were all HER2-negative according to the 2018 guideline, not HER2-positive as defined in the 2013 guideline.

METHODS

We aims to elucidate the unique clinicopathological features of ASCO/CAP Group 2 patients by comparing with classic HER2-nonamplified cancers, and reveal the efficacy of the former to anti-HER2 therapy. The clinicopathological features, treatment and prognosis information of 99 patients between 2014 and 2018 were collected. HER2 status was re-defined using the updated recommendations.

RESULTS

Of the 99 ASCO/CAP Group 2 tumors, 25.5% (25/99) tumors were immunohistochemical (IHC) 0/1+ and 74.7% (74/99) tumors were IHC 2+. According to the updated 2018 guideline, all of them were HER2 negative. When compared to ASCO/CAP Group 5, patients of ASCO/CAP Group 2 displayed higher ratio of histological grade 3 (P = .03), high Ki67 proliferation index (P = .03) and pN3 (more than 9 lymph nodes metastasis, P = .02), and lower estrogen receptor (ER) positivity (P = .04). There was no statistical difference in the survival of patients received anti-HER2 therapy and patients not received anti-HER2 therapy.

CONCLUSIONS

Patients of ASCO/CAP Group 2 did not received apparent benefit from anti-HER2 treatment. Although according to the updated guidelines and latest reports, HER2 is negative, but when compared with classic HER2-nonamplified cancers, patients of this group seemed to be more aggressive. We suggest that this group still be regarded as an independent category, in order to accumulate more cases in the future to expand the scope of research.

Leptomeningeal metastases in patients with human epidermal growth factor receptor 2 positive breast cancer: real-world data from a multicentric European cohort

In patients with human epidermal growth factor receptor 2 positive (HER2+) breast cancer, leptomeningeal metastases (LM) are a rare but often a fatal clinical scenario. In this multicentric study, clinical and pathologic characteristics of patients with HER2+ breast cancer developing LM were described, as well as survival outcomes. Data were gathered retrospectively from medical records of 82 patients with advanced HER2+ breast cancer and LM treated between August 2005 and July 2020. Following LM diagnosis, 79 (96.3%) patients received at least one line of anti‐HER2 therapy, 25 (30.5%) patients received intrathecal therapy and 58 (70.7%) patients received radiotherapy. Overall survival (OS) was 8.3 months (95% confidence interval [CI] 5.7‐11), 1‐year OS was 42%, and 2‐year OS was 21%. At univariate analysis, patients who were treated after 2010, had better Karnofsky performance status, were free of neurological symptoms, had better prognostic, received chemotherapy (OS difference 9.4 months, P = .024), or monoclonal antibodies (trastuzumab ± pertuzumab; OS difference 6.1 months; P = .013) after LM diagnosis, had a statistically significantly longer OS. Presence of neurological symptoms (hazard ratio 3.32, 95% CI 1.26‐8.73; P = .015) and not having received radiotherapy (hazard ratio 2.02, 95% CI 1.09‐3.72; P = .024) were all associated with poorer OS at multivariate analysis. To summarize, not having neurological symptoms and receiving RT at LM diagnosis were associated with prolonged OS in our cohort. Survival seemed to be prolonged with multimodality treatment, which included targeted therapy, chemotherapy, and RT to the LM sites.

Anti-HER2 therapy in metastatic breast cancer: many choices and future directions

Metastatic HER2 + breast cancer is an expanding area of drug development and research, with three new drugs approved in 2020 alone. While first-line therapy is well-established for metastatic HER2 + breast cancer, the standard of care for second-line therapy will likely be changing soon based on the results of the DESTINY-Breast03 trial. In the third-line setting, many options are available. Considerations in choosing between regimens in the third-line include resistance to trastuzumab, the presence of brain metastases, and tolerability. High rates of resistance exist in this setting particularly due to expression of p95, a truncated form of HER2 that constitutively activates downstream signaling pathways. We suggest a tyrosine kinase inhibitor (TKI)-based regimen because of the activity of TKIs in brain metastases and in p95-expressing tumors. Attempts to overcome resistance to anti-HER2 therapies with PI3K inhibitors, mTOR inhibitors, and CDK 4/6 inhibitors are an active area of research. In the future, biomarkers are needed to help predict which therapies patients may benefit from the most. We review the many new drugs in development, including those with novel mechanisms of action.

Prognostic factors of brain metastasis and survival among HER2-positive metastatic breast cancer patients: a systematic literature review

BACKGROUND

Patients with breast cancer who overexpress the human epidermal growth factor receptor 2 (HER2) and subsequently develop brain metastasis (BM) typically experience poor quality of life and low survival. We conducted a comprehensive literature review to identify prognostic factors for BM and predictors of survival after developing BM, and the effects of therapies with different mechanisms of action among patients with HER2+ breast cancer (BC).

METHODS

A prespecified search strategy was used to identify research studies investigating BM in patients with HER2+ BC published in English during January 1, 2009-to June 25, 2021. Articles were screened using a two-phase process, and data from selected articles were extracted.

RESULTS

We identified 25 published articles including 4097 patients with HER2+ BC and BM. Prognostic factors associated with shorter time to BM diagnosis after initial BC diagnosis included younger age, hormone receptor negative status, larger tumor size or higher tumor grade, and lack of treatment with anti-HER2 therapy. Factors predictive of longer survival after BM included having fewer brain lesions (< 3 or a single lesion) and receipt of any treatment after BM, including radiosurgery, neurosurgery and/or systemic therapy. Patients receiving combination trastuzumab and lapatinib therapy or trastuzumab and pertuzumab therapy had the longest median survival compared with other therapies assessed in this review.

CONCLUSIONS

More research is needed to better understand risk factors for BM and survival after BM in the context of HER2+ BC, as well as the assessment of new anti-HER2 therapy regimens that may provide additional therapeutic options for BM in these patients.

Prolonged Survival in Patients with Metastatic HER2-Positive Inflammatory Breast Cancer: A Case Report and Review of the Literature

Inflammatory breast cancer (IBC) is a rare type of breast cancer that is associated with poor outcomes compared with non-IBC. Overexpression of HER2 is enriched in IBC, and those with HER2-positive disease have a relatively favorable prognosis, with improved survival over the last two decades driven by the advent of novel targeted therapies. Here, we present two patients who have survived for over 10 years after being diagnosed with de novo metastatic HER2-positive IBC. We review the data for the treatments available for metastatic HER2-positive IBC and the evolving treatment recommendations for this disease.

A 10-Gene Signature for Predicting the Response to Neoadjuvant Trastuzumab Therapy in HER2-Positive Breast Cancer

BACKGROUND AND PURPOSE

Dual-target therapy may increase the incidence of adverse events and cause economic burden to patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. It is necessary to identify the patients who could benefit greatly from a single-target neoadjuvant therapy in order to avoid overtreatment of patients.

PATIENTS AND METHODS

The baseline transcriptome data and clinical characteristics of patients with HER2-positive breast cancer who received neoadjuvant trastuzumab therapy were obtained from the Gene Expression Omnibus database. Least absolute shrinkage and selection operator (LASSO) regression analyses were used to construct the predictive model for pathologic complete response (pCR).

RESULTS

A 10-gene signature model for predicting pCR rate after neoadjuvant trastuzumab therapy was constructed by LASSO regression. The areas under the receiver operating characteristics (ROC) curves in the training set and validation set were 0.896 (95% confidence interval [CI], 0.8165-0.9758) and 0.775 (95% CI, 0.5402-1), respectively. The result of logistic regression analysis showed that the risk score calculated by the 10-gene signature model was a potential predictor for pCR. Among the 10-gene signature, TFAP2B, SUSD2, AQP3, MUCL1, and ANKRD30A were found to be predictors for worse relapse-free survival (RFS) in patients with HER2-positive breast cancer, whereas MGP, YIF1B, ANKRD36BP2, and FBXO6 were found to be predictors for favorable RFS.

CONCLUSION

A novel 10-gene signature that could predict the response of neoadjuvant anti-HER2 therapy in patients with HER2-positive breast cancer was developed, and the risk score of the 10-gene signature could be calculated to guide the selection of anti-HER2 therapy regimens.

Review of Survival, Safety, and Clinical Outcomes in HER2+ Metastatic Gastric Cancer Following the Administration of Trastuzumab

BACKGROUND

Therapies targeting human epidermal growth factor receptor 2 (HER2) have become a focus for improving treatment outcomes in patients with gastric cancer. This literature review sought to assesses clinical outcomes, including safety, survival, and treatment outcomes, of patients who received trastuzumab for the treatment of HER2+ metastatic gastric cancer.

METHODS

Searches were conducted in PubMed and Embase to identify observational research studies investigating the clinical outcomes of trastuzumab and combination therapies for the treatment of HER2+ metastatic gastric cancer, published January 1, 2014-August 22, 2019. Article screening was a two-phase process, and the results of each screening level were documented in accordance with PRISMA.

RESULTS

Twenty articles met the selection criteria for data extraction. Studies focused on treatment patterns or survival, safety, and clinical outcomes, as well as the natural history of disease. In the combined HER2+ patient populations included in this review, tumors were located in the stomach (33.7%), gastroesophageal junction (GEJ, 14.2%), unspecific GEJ or stomach (50.3%), or esophagus (1.9%). Studies observed increases in both overall survival and progression-free survival with the use of trastuzumab-based chemotherapy compared with chemotherapy treatment alone. Additionally, trastuzumab-based chemotherapy appeared to improve survival and clinical outcomes regardless of the presence of multi-organ metastases or tumor location.

CONCLUSIONS

Trastuzumab-treated patients have longer survival times than those not treated with trastuzumab and tolerate treatment well, with few serious adverse events. New treatments for second- and subsequent-line therapies would increase regimen options.

MINI-ABSTRACT

The treatment patterns and clinical outcomes observed in this literature review suggest patients treated with trastuzumab have longer survival times compared with chemotherapy treatment alone and tolerate treatment.

Patients who achieved long-term clinical complete response and subsequently terminated multidisciplinary and anti-HER2 therapy for metastatic breast cancer: A case series

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Breast cancers that are positive for human epidermal growth factor receptor 2 (HER2) are aggressive and typically associated with a poor prognosis.

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Novel anti-HER2 therapies have recently improved the outcomes in these cases.

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We report a case series in which women were treated for metastatic HER2-positive breast cancer using trastuzumab and various chemotherapies.

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These patients ultimately achieved clinical complete response, and subsequently terminated their systemic therapy after maintenance therapy.

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Our findings indicate that select patients may be suitable for treatment termination if they have achieved a prolonged period of complete response.

Background

Human epidermal growth factor receptor 2 (HER2) -positive breast cancers tend to be more aggressive and more likely to recur than HER2-negative breast cancers. However, novel anti-HER2 therapies have dramatically improved the prognosis of patients with HER2-positive breast cancer.

Case report

We review the cases of 4 women with metastatic breast cancer who achieved clinical complete response (cCR) and terminated their systemic therapy. Two patients had de novo metastatic disease and two patients experienced relapse after adjuvant therapy. All patients achieved cCR using multidisciplinary therapy, experienced prolonged complete remission, and subsequently terminated their systemic therapy without experiencing secondary recurrence.

Conclusion

There is no evidence that systemic therapy can be safely terminated after a specific time period, although adverse events (e.g., cardiotoxicity) and unnecessary treatment should be avoided. Thus, it is possible that select patients may be suitable for termination of systemic therapy after they have achieved a prolonged period of cCR.

Efficacy and safety of trastuzumab, lapatinib, and paclitaxel neoadjuvant treatment with or without prolonged exposure to anti-HER2 therapy, and with or without hormone therapy for HER2-positive primary breast cancer: a randomised, five-arm, multicentre, open-label phase II trial

Background

Dual blockade of HER2 promises increased pathological complete response (pCR) rate compared with single blockade in the presence of chemotherapy for HER2-positive (+) primary breast cancer. Many questions remain regarding optimal duration of treatment and combination impact of endocrine therapy for luminal HER2 disease.

Methods

We designed a randomised phase II, five-arm study to evaluate the efficacy and safety of lapatinib and trastuzumab (6 weeks) followed by lapatinib and trastuzumab plus weekly paclitaxel (12 weeks) with/without prolongation of anti-HER2 therapy prior to chemotherapy (18 vs. 6 weeks), and with/without endocrine therapy in patients with HER2+ and/or oestrogen receptor (ER)+ disease. The primary endpoint was comprehensive pCR (CpCR) rate. Among the secondary endpoints, pCR (yT0-isyN0) rate, safety, and clinical response were evaluated.

Results

In total, 215 patients were enrolled; 212 were included in the full analysis set (median age 53.0 years; tumour size = T2, 65%; and tumour spread = N0, 55%). CpCR was achieved in 101 (47.9%) patients and was significantly higher in ER− patients than in ER+ patients (ER− 63.0%, ER+ 36.1%; P = 0.0034). pCR with pN0 was achieved in 42.2% of patients (ER− 57.6%, ER+ 30.3%). No significant difference was observed in pCR rate between prolonged exposure groups and standard groups. Better clinical response outcomes were obtained in the prolongation phase of the anti-HER2 therapy. No surplus was detected in pCR rate by adding endocrine treatment. No major safety concern was recognised by prolonging the anti-HER2 treatment or adding endocrine therapy.

Conclusions

This study confirmed the therapeutic impact of lapatinib, trastuzumab, and paclitaxel therapy for each ER− and ER+ subgroup of HER2+ patients. Development of further strategies and tools is required, particularly for luminal HER2 disease.

Electronic supplementary material

The online version of this article (10.1007/s12282-018-0839-7) contains supplementary material, which is available to authorized users.

Real-time HER2 status detected on circulating tumor cells predicts different outcomes of anti-HER2 therapy in histologically HER2-positive metastatic breast cancer patients

BACKGROUND

This study was initiated to investigate the difference in HER2 status between tumor tissue and circulating tumor cells (CTCs), as well as the predictive value of CTC HER2 status for predicting the outcomes of anti-HER2 therapy in histologically HER2-positive metastatic breast cancer (MBC) patients.

METHODS

HER2 expression on CTCs was detected using a CellSearch system within 7 days before a new line of anti-HER2 therapy was begun. According to the criterion proposed in our previous report, patients were defined as CTC HER2-positive or -negative. After close follow-up, the correlation between CTC HER2 status and the outcome of the treatment was evaluated by statistical analysis.

RESULTS

CTCs were detected in 57.4 % (58/101) of the patients. Notably, 62.1 % (36/58) of these patients had an inconsistent HER2 status between their tissue and CTCs. The discordant rate may correlate with the time interval between histological and CTC HER2 testing and is more likely to occur in the subgroup of patients with an interval of > 1 year than in those with an interval < 1 year (70.7 % vs. 41.2 %, P = 0.043). For PFS, positive HER2 status on CTCs was shown to be a valuable predictor, both in univariate (HR = 0.321, 95%CI, 0.156-0.62, P = 0.0011) and multivariate (HR = 0.383, 95%CI, 0.166-0.831, P = 0.019) Cox regression analysis. Meanwhile, Kaplan-Meier survival curves revealed that the median PFS of CTC HER2-positive patients was significantly longer than CTC HER2-negative ones (8.5 vs. 3.5 months, P < 0.001).

CONCLUSIONS

HER2 status on CTCs was different from that of tumor tissues and predicted a different outcome of the patients' anti-HER2 therapy. This difference may be correlated with the time interval between tissue and CTC HER2 testing, indicating the necessity of real-time HER2 analysis for histologically HER2-positive MBC patients.

Twenty years of anti-HER2 therapy-associated cardiotoxicity

Over the past 20 years, the prognosis of HER2-positive breast cancer has been transformed by the development of anti-HER2 targeted therapies. In early clinical trials of trastuzumab (ie, the first anti-HER2 agent to be developed) cardiotoxicity became a major concern. In the first published phase 3 trial of trastuzumab, 27% of patients receiving anthracyclines and trastuzumab experienced cardiac events and 16% suffered from severe congestive heart failure. In subsequent trials conducted in advanced and early settings, the incidence of cardiac events was reduced through changes in chemotherapy regimens, more strict patient selection and close cardiac assessment. However, cardiotoxicity remains a significant problem in clinical practice that is likely to increase as new agents are approved and exposure times increase through improved patients' survival. Though numerous trials have led to improved understanding of many aspects of anti-HER2 therapy-related cardiotoxicity, its underlying physiopathology mechanisms are not well understood. The purpose of this article is to provide an in-depth review on anti-HER2 therapy-related cardiotoxicity, including data on both trastuzumab and the recently developed anti-HER2 targeted agents.

The clinical value of HER-2 overexpression and PIK3CA mutations in the older breast cancer population: a FOCUS study analysis

Studies to confirm the effect of acknowledged prognostic markers in older breast cancer patients are scarce. The aim of this study was to evaluate the prognostic value of HER-2 overexpression and PIK3CA mutations in older breast cancer patients. Female breast cancer patients aged 65 years or older, diagnosed between 1997 and 2004 in a geographical region in The Netherlands, with an invasive, non-metastatic tumour and tumour material available, were included in the study. The primary endpoint was relapse-free period and secondary endpoint was relative survival. Determinants were immunochemical HER-2 scores (0/1+, 2+ or 3+) and PIK3CA as a binary measure. Overall, 1698 patients were included, and 103 had a HER-2 score of 3+. HER-2 overexpression was associated with a higher recurrence risk (5 years recurrence risk 34 % vs. 12 %, adjusted p = 0.005), and a worse relative survival (10 years relative survival 48 % vs. 84 % for HER-2 negative; p = 0.004). PIK3CA mutations had no significant prognostic effect. We showed, in older breast cancer patients, that HER-2 overexpression was significantly associated with a worse outcome, but PIK3CA mutations had no prognostic effect. These results imply that older patients with HER-2 overexpressing breast cancer might benefit from additional targeted anti-HER-2 therapy.

SEOM clinical guidelines in metastatic breast cancer 2015

Metastatic breast cancer is essentially an incurable disease. However, recent advances have resulted in a significant improvement of overall survival. The SEOM guidelines are intended to make evidence-based recommendations on how to manage patients with metastatic breast cancer to achieve the best patient outcomes based on a rational use of the currently available therapies. To assign a level of certainty and a grade of recommendation the United States Preventive Services Task Force guidelines methodology was selected as reference.