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

Anthracycline-Free Neoadjuvant Treatment in Patients with HER2-Positive Breast Cancer: Real-Life Use of Pertuzumab, Trastuzumab and Taxanes Association with an Exploratory Analysis of PIK3CA Mutational Status

HER2 is considered one of the most traditional prognostic and predictive biomarkers in breast cancer. Literature data confirmed that the addition of pertuzumab to a standard neoadjuvant chemotherapy backbone (either with or without anthracyclines), in patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (EBC), leads to a higher pathological complete response (pCR) rate, which is known to correlate with a better prognosis. In this retrospective analysis, 47 consecutive patients with HER2-positive EBC received sequential anthracyclines and taxanes plus trastuzumab (ATH) or pertuzumab, trastuzumab and docetaxel (THP). Despite the limited sample size, this monocentric experience highlights the efficacy (in terms of pCR) and safety of THP in the neoadjuvant setting of HER2-positive EBC as an anthracycline-free approach. Given the role of PIK3CA as a prognostic and therapeutic target in breast cancer, tumors were also analyzed to assess the PIK3CA mutational status. Thirty-eight out of forty-seven patients were evaluated, and PIK3CA variants were identified in 21% of tumor samples: overall, one mutation was detected in exon 4 (2.6%), two in exon 9 (5.3%) and four in exon 20 (10.5%). Of note, one sample showed concurrent mutations in exons 9 (codon 545) and 20 (codon 1047). Among patients reaching pCR (n = 13), 38.5% were PIK3CA mutants; on the other hand, among those lacking pCR (n = 25), just 12% showed PIK3CA variants. Regarding THP-treated mutant patients (n = 5), 80% reached pCR (three hormone-receptor-negative, one hormone-receptor-positive). Interestingly, the only patient not achieving pCR had a tumor with two co-occurring PIK3CA mutations. In conclusion, this study provides new evidence about the efficacy and good safety profile of THP, compared to the ATH regimen, as an anthracycline-free neoadjuvant treatment of HER2-positive EBC. Further studies on larger/multicentric cohorts are planned for more in-depth analysis to confirm our molecular and clinical results.

Development and validation of the PORTRET tool to predict recurrence, overall survival, and other-cause mortality in older patients with breast cancer in the Netherlands: a population-based study

BACKGROUND

Current prediction tools for breast cancer outcomes are not tailored to the older patient, in whom competing risk strongly influences treatment effects. We aimed to develop and validate a prediction tool for 5-year recurrence, overall mortality, and other-cause mortality for older patients (aged ≥65 years) with early invasive breast cancer and to estimate individualised expected benefits of adjuvant systemic treatment.

METHODS

We selected surgically treated patients with early invasive breast cancer (stage I-III) aged 65 years or older from the population-based FOCUS cohort in the Netherlands. We developed prediction models for 5-year recurrence, overall mortality, and other-cause mortality using cause-specific Cox proportional hazard models. External validation was performed in a Dutch Cancer registry cohort. Performance was evaluated with discrimination accuracy and calibration plots.

FINDINGS

We included 2744 female patients in the development cohort and 13631 female patients in the validation cohort. Median age was 74·8 years (range 65-98) in the development cohort and 76·0 years (70-101) in the validation cohort. 5-year follow-up was complete for more than 99% of all patients. We observed 343 and 1462 recurrences, and 831 and 3594 deaths, of which 586 and 2565 were without recurrence, in the development and validation cohort, respectively. The area under the receiver-operating-characteristic curve at 5 years in the external dataset was 0·76 (95% CI 0·75-0·76) for overall mortality, 0·76 (0·76-0·77) for recurrence, and 0·75 (0·74-0·75) for other-cause mortality.

INTERPRETATION

The PORTRET tool can accurately predict 5-year recurrence, overall mortality, and other-cause mortality in older patients with breast cancer. The tool can support shared decision making, especially since it provides individualised estimated benefits of adjuvant treatment.

FUNDING

Dutch Cancer Foundation and ZonMw.

Biology of primary breast cancer in older women beyond routine biomarkers

Purpose

There are numerous biomarkers which may have potential predictive and prognostic significance in breast cancer. This is extremely important in older adults, who may opt for less aggressive therapy. This work outlines the literature on biological assessment outside of standard biomarkers (defined as ER, PgR, HER2, Ki67) in women ≥ 65 years with primary operable invasive breast cancer, to determine which additional biomarkers are relevant to outcome in older women.

Methods

Medline and Embase databases were searched. Studies were eligible if included ≥ 50 patients aged ≥ 65 years; stratified results by age; measured a biomarker outside of standard assay and reported patient data.

Results

A total of 12 studies were appraised involving 5000 patients, measuring 28 biomarkers. The studies were extremely varied in methodology and outcome but three themes emerged: 1. Differences in biomarker expression between younger and older women, indicating that breast cancer in older women is generally less aggressive compared to younger women; 2. Relationship of biomarker expression with survival, suggesting biomarkers which may exclusively predict response to primary treatment in older women; 3. Association of biomarker with chemotherapy, suggesting that older patients should not be declined chemotherapy based on age alone.

Conclusion

There is evidence to support further investigation of B-cell lymphoma (BCL2), liver kinase (LK)B1, epidermal growth factor receptor (EGFR), cytoplasmic cyclin-E, mucin (MUC)1 and cytokeratins (CKs) as potential predictive or prognostic markers in older women with breast cancer undergoing surgery. Studies exploring these biomarkers in larger cohorts and in women undergoing non-operative therapies are required.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-021-01266-5.

The Correlation of Mutations and Expressions of Genes within the PI3K/Akt/mTOR Pathway in Breast Cancer-A Preliminary Study

There is an urgent need to seek new molecular biomarkers helpful in diagnosing and treating breast cancer. In this elaboration, we performed a molecular analysis of mutations and expression of genes within the PI3K/Akt/mTOR pathway in patients with ductal breast cancer of various malignancy levels. We recognized significant correlations between the expression levels of the studied genes. We also performed a bioinformatics analysis of the data available on the international database TCGA and compared them with our own research. Studies on mutations and expression of genes were conducted using High-Resolution Melt PCR (HRM-PCR), Allele-Specific-quantitative PCR (ASP-qPCR), Real-Time PCR molecular methods in a group of women with ductal breast cancer. Bioinformatics analysis was carried out using web source Ualcan and bc-GenExMiner. In the studied group of women, it was observed that the prevalence of mutations in the studied PIK3CA and AKT1 genes was 29.63%. It was stated that the average expression level of the PIK3CA, PIK3R1, PTEN genes in the group of breast cancer patients is lower in comparison to the control group, while the average expression level of the AKT1 and mTOR genes in the studied group was higher in comparison to the control group. It was also indicated that in the group of patients with mutations in the area of the PIK3CA and AKT1 genes, the PIK3CA gene expression level is statistically significantly lower than in the group without mutations. According to our knowledge, we demonstrate, for the first time, that there is a very strong positive correlation between the levels of AKT1 and mTOR gene expression in the case of patients with mutations and without mutations.

PIK3CA Mutations and Neoadjuvant Therapy Outcome in Patients with Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: A Sequential Analysis

Purpose

PIK3CA mutation is considered to be a possible cause for resistance to neoadjuvant chemotherapy (NAC) in human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We investigated the association between PIK3CA mutations and the outcome of NAC in HER2-positive breast cancers.

Methods

A total of 100 HER2-positive breast cancer patients who had undergone NAC and surgery between 2004 and 2016 were examined. Mutation status was sequentially assessed in pre-NAC, post-NAC, and recurrent specimens taken from these patients.

Results

PIK3CA mutations were identified in the sequential specimens of 17 patients (17.0%). These 17 patients experienced shorter disease-free survival (DFS) than the rest of the patients (58.3 months vs. 119.3 months, p=0.020); however, there was no significant difference in pathologic complete response (pCR) and overall survival (OS) (pCR, 17.6% vs. 33.7%, p=0.191; OS, 84.5 months vs. 118.0 months, p=0.984). While there was no difference in pCR between the wild-type and mutant PIK3CA groups in pre-NAC specimens (25.0% vs. 31.8%, p=0.199), PIK3CA mutations correlated with lower pCR in post-NAC specimens (0.0% vs. 24.3%, p<0.001). Multivariate analysis revealed significantly worse DFS in the mutant PIK3CA group than in the wild-type group (hazard ratio, 3.540; 95% confidence interval, 1.001–12.589; p=0.050). Moreover, the DFS curves of the change of PIK3CA mutation status in sequential specimens were significantly different (p=0.016).

Conclusion

PIK3CA mutation in HER2-positive breast cancer was correlated with a lower pCR rate and shorter DFS. These results suggest that PIK3CA mutation is a prognostic marker for NAC in HER2-positive breast cancer, especially in post-NAC specimens.

Prevalence and Prognostic Role of PIK3CA/AKT1 Mutations in Chinese Breast Cancer Patients

Purpose

The prevalence of PIK3CA in Chinese breast cancer patients may be underestimated. Therefore, we investigated the distribution of somatic PIK3CA/AKT1 mutations in Chinese breast cancer patients and explored their roles in tumor phenotypes and disease prognosis.

Materials and Methods

Tumors from 507 breast cancer patients were prospectively collected from the West China Hospital between 2008 and 2013. Whole exons of AKT1 and PIK3CA were detected in fresh-frozen tumors using next-generation sequencing, and correlations between PIK3CA/AKT1 mutations and clinicopathological features were analyzed.

Results

The AKT1 mutation was found in 3.6% (18/507) of patients. Tumors from patients that carried the AKT1 mutation were estrogen receptor (ER)+/progesterone receptor (PR)+/human epidermal growth factor receptor 2 (HER2)‒ and were more likely to have high expression levels of Ki67. The prevalence of the PIK3CA mutation was 46.5% (236/507), and 35 patients carried two or three variants of the PIK3CA gene. PIK3CA mutations were associated with ER+/PR+/HER2‒ status. The prognosis of patients with one mutation in PIK3CA (or PIK3CA/AKT1) was not significantly different than that of patients with wild-type PIK3CA (or PIK3CA/AKT1), while patients with two or three variants in PIK3CA (or PIK3CA/AKT1) exhibited poorer outcomes in the entire group and in all three subgroups (ER+, HER2‒, Ki67 high), particularly with respect to overall survival.

Conclusion

A high frequency of somatic PIK3CA mutations was detected in Chinese breast cancer patients. In addition to the mutation frequency, the tumor mutational burden of the PIK3CA and AKT1 genes should also be of concern, as they may be associated with poor prognosis.

Adjuvant systemic therapy in older women with breast cancer

Breast cancer in the elderly is an increasing clinical problem. In addition, ~60% of deaths from breast cancer occur in women aged 65 years and older. Despite this, older women with breast cancer have been underrepresented in clinical trials, and this has led to less than optimal evidence to guide their therapy. The management of elderly women with early breast cancer is a complex process that requires careful evaluation of life expectancy, comorbidities, patient values, and risks and benefits of available treatment options. This review will focus on current adjuvant systemic therapy options for older women with breast cancer, discuss the principles in the decision-making process, and define the role of endocrine therapy, chemotherapy, and targeted agents.