Abstract
Objectives
This study aims to analyze the prevalence and spectrum of epidermal growth factor receptor (EGFR) mutations within the Middle East and North Africa region, compare the findings to other parts of the world, and explore the geographic disparities of EGFR mutations across the region.
Methods
We conducted a literature search using the terms “[EGFR] AND [mutation] AND [Non-Small Cell Lung Cancer] AND [Middle East OR North Africa]”, using PubMed, Science Direct, Web of science, Embase, Scopus, and Google scholar.
Results
A total of 15 eligible studies were included and 6122 patients with non-small cell lung cancer (NSCLC) were analyzed. Male patients were predominant in all of the considered studies, accounting for 70.4%. Of the included patients, 65.6% were smokers and 88.3% had been diagnosed with adenocarcinoma. Overall, EGFR mutations prevalence was 17.2%. In the Middle East, the reported frequency was 16.5%, ranging from 11.3% in Lebanon to 29.7% in the Gulf region. In North Africa, the prevalence of EGFR mutations was 18%, ranging from 17.5% in Egypt to 21.5% in Morocco. The most prevalent mutations were the exon 19 deletions (46.7%) followed by exon 21 substitutions (31.1%). Exon 20 alterations were detected in 10.8% of the analyzed cases, whereas exon 18 mutations were reported in 3.4% of the EGFR-mutated patients. There was 1.1% of patients that had concurrent EGFR mutations. Overall, EGFR mutation prevalence was higher in females [females vs males: 29.7% vs 5.9%, P<.001], non-smokers [non-smokers vs smokers: 31.3% vs 9.6%, P<.001], and patients with adenocarcinoma [adenocarcinoma vs non-adenocarcinoma: 18.8% vs 6.5%, P<.001].
Conclusion
EGFR mutation prevalence among the Middle East and North Africa populations is slightly higher than that seen in NSCLC patients of Caucasian ethnicity but is lower than that identified in Asian NSCLC patients. The distribution of these mutations varies considerably throughout the region.
Introduction
Lung cancer remains a major public health issue, being the leading cause of cancer-related mortality worldwide. In 2020, the death toll from lung cancer reached 1.8 million deaths globally. In terms of incidence rates, lung cancer is the second most prevalent malignancy with 2,2 million new diagnosed cases worldwide. 1 In the Middle East and North Africa region, while lower incidence and mortality rates are estimated, a gradual increase in these figures is witnessed.2,3 Lung cancer incidence rates increases are more eminent among older age groups. 4
Lung carcinomas are categorized by the size and appearance of the malignant cells and are divided into 2 broad categories of small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). NSCLC is a highly heterogeneous disease and is mainly divided into 3 major histological subtypes: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.5,6 NSCLC has been regarded as a distinct biological subset, characterized with molecular alterations that are targets to available or promising personalized therapies. 7 The ever changing landscape of NSCLC treatment have been revolutionized by the discovery of epidermal growth factor receptor (EGFR) mutations. 8
EGFR is a transmembrane glycoprotein receptor endowed with a tyrosine kinase activity, being a member of the ErbB receptor tyrosine kinase (TK) family. 9 The activation of EGFR with its specific ligands induces receptor dimerization and tyrosine autophosphorylation, leading to cell survival, proliferation, migration, and metastasis. 10 Sensitizing EGFR mutations lead to constitutive activation of the receptor, independently of the presence of the ligand, promoting oncogenic phenotypes including, heightened cell division and invasion. 11 In NSCLC, these alterations play a role in sensitizing the receptor to tyrosine kinase inhibitors (TKIs), as EGFR-mutated patients show a 70% to 80% response rate to TKIs, and act as predictive markers for the response to TKIs. 12 EGFR mutations in exons 18 to 21 are more common in patients with adenocarcinomas, in women, and in non-smokers. 13
Previous studies have reported that EGFR mutation rates are influenced by ethnicity. The highest frequencies were seen among Asian patients (40%-50%), whereas the lowest were found in Caucasian patients (10%). 14 In the MENA countries, reports on the prevalence of EGFR mutations lack dramatically, as EGFR molecular characterization is not standard of care in most countries. This calls for a surge in EGFR mutation testing in the region, in order to have an accurate depiction of EGFR mutation prevalence and spectrum.
In this study, we conducted a systematic review of the literature in order to determine the prevalence and patterns of EGFR mutations in NSCLC patients of the region, to position the findings in the international context, and to highlight the correlation between these alterations’ rates and patients’ clinicopathological characteristics.
Methods
We conducted a systematic review of literature published on
The included studies had to meet the following criteria: the study must relate to the role of the
This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyse (PRISMA) guidelines. 15
Statistical Analysis
The potential correlations between EGFR mutation status and patients’ clinicopathological characteristics were analyzed using χ2 statistics. A
Results
Literature Research
The initial literature search in the queried databases yielded 29 publications. An additional study that was identified through article references. Of the 30 publications, 24 studies were selected after the elimination of redundancies. These articles were assessed for eligibility and 15 studies were selected for this review: 11 (73.3%) from the Middle East16-26 and 4 (26.6%) in North Africa.27-30 Original articles were identified from Jordan,
16
Iran,
17
Turkey,18-20 Iraq,
22
Lebanon,23-25 Morocco,27-29 and Egypt.
30
A multicenter prospective study from the Levant (Lebanone, Syria, Palestine, Jordan, Iraq, and Egypt)
26
and a multisite retrospective study from the Gulf (Saudi Arabia, the United Arab Emirates and Qatar) were also identified and will be part of our analysis.
21
(Figure 1). Flow chart of the studies identified and included in this review.
Description of Sample Sizes and Included Regions
We identified 15 eligible studies: 11 (73.3%) in the Middle East16-26 and 4 (26.6%) in North Africa.27-30 EGFR exons 18 through 21 mutations were assessed in 14 out of the 15 considered studies, in 88.5% (5419/6122) of the analyzed patients: Jordan (1 study, 166 patients), 19 Iran (1 study, 103 patients), 17 Turkey (2 studies, 1368 patients),18,19 the Gulf Region (1 study, 230 patients), 21 Iraq (1 study, 138 patients), 22 Lebanon (3 studies, 477 patients),23-25 the Levant region (1 study, 210 patients), 26 Morocco (3 studies, 710 patients),27-29 and Egypt (1 study, 2017 patients). 30 One study from Turkey (703 patients), did not specify EGFR exons genotyped. 20
Specimens and Methods used in the EGFR Mutation Analysis
Characteristics of the Included Studies.
Patients’ Clinicopathological Characteristics
Overall,
EGFR Mutation Prevalence
Correlation Between Clinicopathological Features Of Included Patients and the EGFR Mutational status.
EGFR Mutation Spectrum
Overall, the most frequently encountered
Concurrent mutations were found in 1.1% (12/1054) of the included patients. A total of 10 Turkish patients had multiple exon mutations.18,19 A single Turkish study reported that 8 patients harbored concurrent mutations: 1 patient had mutations in exon 18 and exon 19, 3 patients had mutations in exon 18 and exon 21, 1 patient had mutations in exon 19 and exon 21, and 3 patients had mutations in exon 20 and exon 21.
18
In 2 Turkish cases, exon 19 deletions and exon 20 T790 M point mutation were detected together in a single patient, and exon 21 L858 R mutation and exon 18 G718X point mutation were found together in another patient.
19
A single Jordanian patient carried 4 concurrent mutations: A735 T, D770_N771 insY, G719 A, L861Q, and L858P.
16
One
Association Between EGFR Mutations and Patients’ Clinicopathological Characteristics
Distribution of EGFR Mutations among Included Patients by Mutation Type.
Discussion
In the present report, we provide updated data about EGFR mutations in the Middle East and North Africa, offering a better insight into EGFR mutation prevalence and spectrum in different subgroups of NSCLC patients of the region. This information is particularly useful in informing policy makers of patients’ subgroups who are more likely to benefit from TKI treatment. Since the occurrence of the dramatic shift in treatment, from the all-encompassing chemotherapy approach to the personalized therapeutic strategies, NSCLC patients genotyping for EGFR mutations has become an absolute necessity for lung cancer management. While EGFR molecular epidemiology varies depending on, inter alia, ethnicity, very little is known about EGFR mutational status of NSCLC patients in the region.
This systematic review revealed that EGFR mutation prevalence among the Middle East and North Africa populations is higher than that seen in NSCLC patients of Caucasian ethnicity but is lower than that identified in Asian NSCLC patients. Furthermore, it was found that the distribution of these mutations varies considerably throughout the MENA region, an expected outcome since mutation rates are known to vary depending on geographic locations and racial/ethnic backgrounds of the demographically heterogenous populations of the region.
Overall, the EGFR mutation rate was 17.2%, as 1054 of 6122 patients harbored mutations in at least 1 of the considered exons. Exon 19 deletions were the most frequently encountered mutations (46.7%). EGFR exon 19 deletions accounted for 49.9% in NA and 43% in ME. These figures corroborate data from the literature reporting an average frequency of 40% regarding exon 19 deletions. 31 Exon 21 made up 31.1% of the identified mutations (29% in NA and 32.2% in ME). Exon 20 mutations accounted for 10.8% of the detected alterations (13.3% in NA and 7.6% in the ME), of which the T790 M tyrosine kinase inhibitors (TKIs) resistant mutation was the most prevalent (5.7%). Data regarding patients’ treatment lacked from the considered studies, therefore, little is known about whether the T790 M mutations were detected in TKI-naïve patients at diagnosis or in patients whose disease progressed on first- or second-generation TKI therapies. Also, the use of highly sensitive techniques (eg qPCR-based assays) in a wide range of the considered studies might have contributed to the high prevalence of an otherwise uncommon EGFR mutation. The least prevalent EGFR alterations were exon 18 mutations, making up 3.4% (1.8% in NA and 6% in the ME).
The EGFR mutation status was associated with the female gender [females vs males: 29.7% (294/989) vs 5.9% (248/4200),
Deletions in exon 19 and alterations in exon 21 are the most common EGFR mutations, together, they account for 90% of all
These results corroborate those obtained by Benbrahim et al on the frequency of EGFR mutations in the MENA region. They found that EGFR mutations are more frequent in the Middle East and North African populations than in Caucasian populations but still lower than frequencies reported among Asian populations. Also, they reported that the most frequent EGFR alterations detected were exon 19 deletions. The EGFR mutation status was found to correlate with both female sex and non-smoking status, but not with the histological subtype. 36
In concordance with previous reports, Rondell et al, reported a frequency of 16.1% of EGFR-mutated cases among African and Middle Eastern NSCLC patients, in a large scale study involving 23 757 patients from different parts of the world: Northern Asia, Southern Asia, Europe, Africa (including the Middle East), South America, and North America. Among the studied cases, Taiwan had the highest rate of EGFR-activating mutations [55% (2802/5103)], followed by China [37% (1009/2702)], then Japan [29% (9644/32 935)] and lastly India with a rate of 29% (605/2077). While The highest rates were recorded in Asia, the lowest were in South America with 7,9% (114/1439). In Europe, the frequency of EGFR mutations was 13.4% (138/1030). In North America, where the largest studied population was (86 654 patients), 9,2% carried EFGR mutations. 37
A major strength of this systematic review is the inclusion of available studies from a wide range of MENA countries and covering the diverse populations of the region, without compromising the statistical power of the study, in order to have an accurate depiction of EGFR mutation prevalence and spectrum in the area.
Although results from this study were consistent with findings from previous reports, they should be considered cautiously due to some limitations. Firstly, the types of specimens and genotyping methods used in the included studies lacked homogeneity; in some studies, the mutations were confirmed by sequencing whereas in others they were not. Secondly, the restricted access of patients to EGFR molecular testing in some countries of the region could induce a disproportion in study population size to NSCLC patients in the country, potentially creating some bias in the study. Finally, the demographically non-homogeneous nature of the populations of the region could potentially contribute to the heterogeneity of the study.
Conclusion
EGFR mutation prevalence among MENA populations is slightly higher than that seen among NSCLC patients of Caucasian ethnicity but is lower than that identified in Asian NSCLC patients. The distribution of these mutations varies considerably throughout the MENA region. These estimates can serve as a reference for the future research or policy making. While EGFR molecular epidemiology varies depending on, inter alia, ethnicity, very little is known about EGFR mutational status of NSCLC patients in the region. This entails the introduction of EGFR mutation analysis as standard of care for NSCLC patients in the region.
Footnotes
Acknowledgments
We sincerely thank the editor and the reviewers for providing comments to improve the paper.
Authors’ Contributions
YB and AL have conceived the study, exploited data, coordinated and drafted the paper. TB, BElM, HElA, and HC participated in the study design. HS, HE, IAR and, TM were involved in data analyses. YS, BB, KE, IL-A, MI, RT, AA, and MO critically reviewed the manuscript. All authors have read and agreed to the published version of the manuscript.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Availability of Data and Materials
The data that support the findings of this study are available from original articles that have been included in this study. Data are available from the authors upon reasonable request from the corresponding author.
