Human epidermal growth factor receptor 2 status of gastric cancer patients in Asia: results from a large, multicountry study

Predictive Factors Associated with Survival in Female Gastric Cancer Patients in Southeast Asia

Introduction

Association of Southeast Asian Nations (ASEAN) countries have high Helicobacter pylori infections, and gastric cancer (GC) is a leading fatal cancer in this region, especially in female patients. This study aimed to compare clinical manifestations, histopathological subtypes, and prognostic factors associated with the overall survival rate of female GC patients in this important region.

Methods

This retrospective cohort study was conducted between 2007 and 2022 at a tertiary care center in Thailand. All clinical information, endoscopic findings, and histological types were extensively reviewed. Furthermore, all qualified studies in ASEAN published in PubMed and Scopus between 2000 and 2022 were extracted and thoroughly analyzed. Young female GC patients are defined as those ≤50 years of age.

Results

A total of 98 Thai female GC patients were included, with a mean age of 58.99 ± 14 years; 70.4% were elderly women. The common presenting symptoms were weight loss (69.4%) and dyspepsia (68.4%). Younger female GC patients had significantly more common diffuse-type GC than elderly female GC patients (82.8% vs. 53.6%, p-value = 0.007). Moreover, elderly female GC patients demonstrated significantly better survival than younger female GC patients (44.8% vs. 20.7%, odds ratio = 3.49; 95% confidence interval: 1.20-10.14, p-value = 0.022). Furthermore, a total of 1,491 female GC patients from ASEAN were reviewed and included in this study, aged 15 to 93 years. The top three countries with the highest proportion of female GC from ASEAN were Indonesia (66.7%), Thailand (44.9%), and Singapore (38.4%).

Conclusion

GC in women is not uncommon in ASEAN and presents at an advanced stage with a grave prognosis. This study showed that ASEAN countries with the highest disease burden were Indonesia, Thailand, and Singapore. Overall, survival rates for female GC patients in ASEAN countries were relatively low, highlighting the need for proactive measures such as intensive H. pylori eradication and the development of early detection methods for GC.

A comparative study of gastric adenocarcinoma HER2 IHC phenotype and mass spectrometry-based quantification

Introduction

Gastric cancer is a highly heterogeneous malignant tumor of the digestive system. Anti-HER2 treatment can inhibit downstream signaling pathways and improve clinical treatment and outcomes in patients with HER2 protein overexpression. Currently, two standard methods for evaluating HER2 expression status are immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). However, these low-throughput assays often produce discordant or equivocal results.

Methods

In this study, we presented a new HER2 protein detection method based on mass spectrometry selected reaction monitoring (MS-SRM) and validated the method. We conducted a retrospective study on 118 formalin-fixed paraffin-embedded (FFPE) tissues from patients with advanced gastric adenocarcinoma in northern China, and we compared the MS-SRM results with those from IHC and correlated them with FISH.

Results

We established and validated the upper and lower detection limits (300-700 amol/μg) for abnormal HER2 protein expression in advanced gastric cancer. We also found that, among samples with mixed Lauren subtypes, those with a high level of HER2 expression had typical intestinal type features in pathology.

Discussion

This study demonstrated that the MS-SRM method can overcome the limitations and deficiencies of IHC, directly quantify the expression of HER2 protein in tumor cells and be used as a supplement to IHC. It has the potential to be used as a companion diagnosis for new drugs used to treat advanced gastric cancer. Large-scale clinical validation is required.

Impact of HER2 on prognosis and benefit from adjuvant chemotherapy in stage II/III gastric cancer patients: a multicenter observational study

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is a well-developed therapeutic target in breast and gastric cancer (GC). However, the impact of HER2 on survival and benefit from fluorouracil-based adjuvant chemotherapy remains unclear in patients with GC.

MATERIALS AND METHODS

This multicenter cohort study involved 5622 consecutive stage II/III GC patients. HER2 expression was assessed prospectively via immunohistochemistry (IHC). The staining intensity was graded on a scale of 0 to 3+. An IHC score of 2+or 3+was defined as high expression, and a score of 3+was defined as overexpression.

RESULTS

HER2 overexpression was independently associated with a lower 5-year overall survival (OS) in stage II [hazard ratio (HR), 2.10; 95% CI: 1.41-3.11], but not in stage III GC (HR, 1.00; 95% CI, 0.82-1.20). Further analysis revealed that stage II patients with high HER2 expression showed a poorer response to chemotherapy than stage II patients with low HER2 expression ( Pinteraction =0.024). The HRs for 5-year OS were 0.51 (95% CI, 0.38-0.70) for stage II patients with low HER2 expression, 0.58 (95% CI, 0.51-0.66) for stage III patients with low HER2 expression, 1.13 (95% CI, 0.61-2.09) for stage II patients with high HER2 expression, and 0.47 (95% CI, 0.36-0.61) for stage III patients with high HER2 expression.

CONCLUSIONS

Fluorouracil-based adjuvant chemotherapy is insufficient for stage II GC patients with high HER2 expression, indicating that prospective trials are required to validate alternative HER2-targeted adjuvant therapies in the individuals above.

Immune microenvironment characteristics and their implications for immune checkpoint inhibitor efficacy in HER2-overexpressing gastric cancer

HER2-positive gastric cancer is a distinct tumor subtype, accounting for ~10% of gastric cancer cases. It is characterized by HER2 overexpression and responds well to HER2-targeting therapies. Recently, the addition of immune checkpoint inhibitors to HER2-targeting therapies produced satisfactory outcomes in these patients. In the present study, we used gene expression profiles and patient surgical sections to analyze the tumor immune microenvironment characteristics of gastric tumors with high HER2 expression. Several differentially enriched pathways were identified between the HER2 high-expression group and the low-expression group, such as pathways related to cytokine-cytokine receptor interactions, calcium signaling, and cell adhesion molecules. Tumors with high HER2 expression comprised fewer stromal cells and fewer immune cells, and had higher tumor purity. They also presented with lower expression of PD-1, PD-L1, CTLA-4, TIGIT, and LAG-3. In conclusion, our study provides a comprehensive blueprint of the immune microenvironment of HER2-positive gastric tumors. This analysis highlights the importance of considering the tumor microenvironment when assessing response to immune checkpoint inhibitors.

Clinicopathologic features and treatment advances in cancers with HER2 alterations

HER2 is one of the most important proteins of the epidermal growth factor receptor (EGFR) family, whose alterations include amplification, overexpression and gene mutation. Growing attention has been given to HER2 as a biomarker for prognosis, an indicator for treatment response and a target for new drugs. Tumors with HER2 alterations have been well studied in multiple locations as distinct entities for treatment, especially breast cancer, gastric cancer, lung cancer and colorectal cancer. These four cancers are the leading causes of cancer incidence and cancer-related death worldwide. The present study details the landscape of HER2 amplification/overexpression and mutations and gives an up-to-date analysis of current clinical trials in the four cancers mentioned above. Different HER2-altered cancers not only respond differently to HER2-targeting therapies but also display diverse survival outcomes. Even in the same type of cancer, HER2 amplification/overexpression differs from HER2 mutation in terms of clinicopathologic features and treatment strategies. As an emerging strategy in cancer treatment, immune checkpoint inhibitors demonstrate distinct outcomes in HER2-altered breast cancer, gastric cancer and lung cancer.

Breast Cancer Incidence Trends by Estrogen Receptor Status Among Asian American Ethnic Groups, 1990-2014

Background

Westernization and etiologic heterogeneity may play a role in the rising breast cancer incidence in Asian American (AA) women. We report breast cancer incidence in Asian-origin populations.

Methods

Using a specialized Surveillance, Epidemiology, and End Results-9 Plus API Database (1990-2014), we analyzed breast cancer incidence overall, by estrogen receptor (ER) status, and age group among non-Hispanic white (NHW) and AA women. We used age-period-cohort models to assess time trends and quantify heterogeneity by ER status, race and ethnicity, and age.

Results

Overall, breast cancer incidence increased for most AA ethnicities (Filipina: estimated annual percentage change [EAPC] = 0.96%/year, 95% confidence interval [CI] = 0.61% to 1.32%; South Asian: EAPC = 1.68%/year, 95% CI = 0.24% to 3.13%; Chinese: EAPC = 0.65%/year, 95% CI = 0.03% to 1.27%; Korean: EAPC = 2.55%/year, 95% CI = 0.13% to 5.02%; and Vietnamese women: EAPC = 0.88%/year, 95% CI = 0.37% to 1.38%); rates did not change for NHW (EAPC = -0.2%/year, 95% CI = -0.73% to 0.33%) or Japanese women (EAPC = 0.22%/year, 95% CI = -1.26% to 1.72%). For most AA ethnicities, ER-positive rates statistically significantly increased, whereas ER-negative rates statistically significantly decreased. Among older women, ER-positive rates were stable for NHW and Japanese women. ER-negative rates decreased fastest in NHW and Japanese women among both age groups.

Conclusions

Increasing ER-positive incidence is driving an increase overall for most AA women despite declining ER-negative incidence. The similar trends in NHW and Japanese women (vs other AA ethnic groups) highlight the need to better understand the influences of westernization and other etiologic factors on breast cancer incidence patterns in AA women. Heterogeneous trends among AA ethnicities underscore the importance of disaggregating AA data and studying how breast cancer differentially affects the growing populations of diverse AA ethnic groups.

Budget Impact of Switching to Biosimilar Trastuzumab (CT-P6) for the Treatment of Breast Cancer and Gastric Cancer in 28 European Countries

BACKGROUND

As the economic burden of treating cancer patients has been soaring in European countries, performing a budget impact analysis is becoming one of the requirements for payers' application dossiers.

OBJECTIVE

The objective of this study was to estimate the budgetary impact of introducing the biosimilar trastuzumab (CT-P6) from the payer's perspective and to determine the number of additional patients who could be treated with resulting savings in 28 European countries.

METHODS

A budget impact model was developed to analyze the financial impact of switching from originator trastuzumab to biosimilar CT-P6 in the treatment of early and metastatic breast cancer and metastatic gastric cancer with a time horizon of 1-5 years. Budgetary savings and the number of patients potentially affected were measured based on epidemiological and sales volume data. The base-case analysis assumed that the price of CT-P6 is 70% of the originator price, the switching rate of originator to CT-P6 in the first year is 20%, and the annual growth in the switching rate for each subsequent year is 5%.

RESULTS

For analyses using the base-case scenario following CT-P6 introduction, the total estimated budgetary savings over a 5-year period (depending on the scenario) ranged from €1.13 billion to €2.27 billion based on epidemiological data, or from €0.91 billion to €1.82 billion based on sales volume data. In the first year only, the projected budgetary savings ranged from €58 million to €136 million, and the number of additional patients who could be treated using the savings ranged from 3503 to 7078 by sensitivity analysis.

CONCLUSIONS

The conducted budget impact analysis assessing a switch from originator trastuzumab to biosimilar CT-P6 in 28 European countries indicates that budget savings could be between €0.91 billion and €2.27 billion over the next 5 years. These savings could be used to help improve patient access to local biologics in their respective countries while simultaneously strengthening the overall public health landscape across the European Union.

Prognostic importance of PTEN, EGFR, HER-2, and IGF-1R in gastric cancer patients treated with postoperative chemoradiation

Background/aim

This study aimed to describe the prognostic importance of epidermal growth factor (EGFR), phosphatase and tensin homolog (PTEN), human EGF receptor-2 (HER-2), and insulin-like growth factor 1 receptor (IGF-1R) in gastric cancer patients treated with postoperative chemoradiation therapy.

Materials and methods

Sixty-nine patients treated with adjuvant chemoradiation therapy were retrospectively evaluated. Tumor samples were stained immunohistochemically.

Results

All patients were treated with 3D conformal radiation therapy with concomitant and adjuvant chemotherapy. Perineural invasion (PNI) (P = 0.042), prechemoradiation therapy albumin levels below 3.5 mg/dL (P = 0.011), and EGFR positivity (P = 0.008) had negative effects on overall survival (OS). The median OS was 26 months for patients with PNI (+), 34.9 months for those with PNI (–), 19.5 months for those with albumin levels below 3.5 mg/dL, and 33.2 months for those with albumin levels above 3.5 mg/dL. IGF-1R (+) (P = 0.035) and history of cigarette smoking (P = 0.033) were observed to have a statistically significantly negative effect on disease-free survival (DFS). The median DFS was 29.2 months for IGF-1R (+) patients, 37.9 months for those with IGF-1R (-), and 26.3 and 40.59 months for smokers and nonsmokers, respectively.

Conclusion

IGF-1R and EGFR may be used for patient selection in future prospective studies that evaluate the prognostic importance of these receptors.

Prevalence of HER2 Expression and Its Correlation with Clinicopathological Parameters in Gastric or Gastroesophageal Junction Adenocarcinoma in North-East Indian Population

Objective: Human epidermal growth factor receptor 2 (erbb2/HER2) overexpression, has now been implicated in advanced gastric and gastroesophageal junction cancers. The study was conducted to determine the rate of HER2 positivity in patients with locally advanced or metastatic gastric and gastroesophageal adenocarcinoma in North-East India and to assess the impact of various demographic and clinical parameters on HER2 positivity. Methods: A total of 68 patients of age >18 years of gastric and gastroesophageal adenocarcinoma diagnosed on histopathological examination from September 2016 to February 2018 at Dr B Borooah Cancer Institute, Assam were enrolled for the observational (epidemiological) study. All patients were subjected to the HER2 immunohistochemistry test using a FDA-approved, standardized test kit. HER2 expression was correlated with various demographic and clinicopathological parameters. Results: The overall rate of HER2 positivity in the population studied was 56% (n=38). The rate was non-significantly higher in male, older age group (>60 years) and Hindu population. Similarly, HER2 positivity rate was higher in patients with well differentiated histology and was more common in patients with stage II and III diseases, but neither of the associations is statistically significant. HER2 positivity rate was significantly higher in proximal and in GEJ tumours (56% versus 44%, P=0.002). Conclusion: HER2 overexpression was evident in 56% of the North-East Indian patients with locally advanced and metastatic gastric and gastroesophageal adenocarcinoma. The overexpression correlated significantly with primary tumour site. Routine testing of gastric and gastroesophageal tumours for HER2 expression is recommended to provide a therapeutic advantage in Indian patients.

Detection of ERBB2 (HER2) Gene Amplification Events in Cell-Free DNA and Response to Anti-HER2 Agents in a Large Asian Cancer Patient Cohort

Background: HER2 antagonists have marked activity and are approved for the treatment of HER2 overexpressing breast and gastric cancers. Recent studies have shown that ERBB2 (HER2) gene amplification and overexpression may also be actionable in other tumor types. Inter- and intratumoral heterogeneity in HER2 status, however, poses a significant challenge in identifying patients that may benefit from HER2-targeted therapies. ERBB2 amplification as identified by circulating cell-free DNA (cfDNA), which circumvents tissue heterogeneity issues, is emerging as a robust biomarker predictive of response to anti-HER2 agents. Here, the prevalence and genomic landscape of ERBB2 alterations detectable by next-generation sequencing (NGS) of cfDNA was evaluated in a large cohort of Asian patients with advanced solid tumors. Methods: Results were queried for consecutive patients (n = 469) tested by a comprehensive 70/73-gene cfDNA NGS assay (Guardant360®) between November 2015 and June 2018. Patients with ERBB2 gene alterations including copy number amplifications (CNAs), single nucleotide variants (SNVs), and insertion-deletions (indels) were identified. Results: ERBB2 alterations were detected in 52 patients (11.1%); ERBB2 SNVs, CNAs, and indels were found in 27 (5.8%), 27 (5.8%), and 10 (2.1%) patients, respectively. ERBB2 amplification was most frequently identified in gastric (21.4%; 6/28), colorectal (11.1%; 5/45), lung (3.9%; 9/231), and breast (3.2%; 1/31) cancer patients. ERBB2 amplification was often mutually exclusive with other oncogenic alterations in gastric (83.3%; 5/6) and colorectal (60%; 3/5) cancer patients. ERBB2 copy number gains were also highest in gastric and colorectal cancers (median 4.8 and 6.6, respectively). We further report two cases of advanced gastric cancer patients, one treatment naïve, and the other having failed four lines of therapy, whose ERBB2 CNAs were identified by cfDNA and derived clinical benefit from HER2-based therapies. Conclusion: Our data indicate that ERBB2 amplification is a common event in solid tumors among Asian cancer patients. High ERBB2 incidence and copy number gains were observed in gastric and colorectal cancer patients, often in the absence of other oncogenic mutations, underscoring its likely role as the driver alteration in those settings. Finally, we show the potential of comprehensive cfDNA testing in identifying patients who are most likely to benefit from HER2-targeted therapies.