Cancer prevalence, incidence, and mortality rates in Afghanistan in 2020: A review study

Abstract Background Afghanistan is in an epidemiological transition, as cancer is the second leading cause of mortality due to non‐communicable diseases. This study is the first to provide a comprehensive perspective on the overall cancer situation in Afghanistan by discussing the top five most common cancers, their incidence variations, risk factors, and preventive measures. The limited number of cancer studies conducted in Afghanistan highlights the importance of the present review. Recent Findings This article provides an overview of cancer burden in Afghanistan in 2020. It utilizes IARC‐generated GLOBOCAN 2020 data for one, three, and five‐year prevalence rates, the estimated number of new cancer cases, and mortality rates by age group in Afghanistan. According to GLOBOCAN, the top five common cancers in both sexes in Afghanistan were breast (n = 3173, 14.3%), stomach (n = 2913, 7.8%), lung (n = 1470, 6.6%), cervix uteri (n = 1200, 5.4%), and colorectum (n = 1084, 4.9%). Conclusion This study provides a brief overview of the general cancer situation in Afghanistan, and a more in‐depth analysis of the five common cancers identified. Effective therapies, awareness, and prevention initiatives targeting lifestyle, immunization, early diagnosis, and environmental risk factors are essential for addressing the impact of population growth and aging on cancer incidence in Afghanistan. Further research and extensive studies are needed to better understand cancer burden in the country.

Afghanistan is a landlocked and mountainous country with a population of 38 million people located within South Asia and Central Asia, bordering China, Pakistan, Iran, Turkmenistan, Uzbekistan, and Tajikistan. According to the WHO, life expectancy at birth in Afghanistan is 60 years for men and 61 years for women. Afghanistan is in an epidemiologic transition and faces a double disease burden.
Cancer is the second leading cause of mortality due to noncommunicable diseases in Afghanistan. According to the most recent WHO Afghanistan country profile report, 19 450 cancer cases and 14 746 cancer-related deaths were reported in 2018. According to this report, breast, stomach, lip/oral cavity, esophagus, and lung cancers had the highest cancer incidence, and so did cancer-related deaths. 4 As very few studies on the epidemiology and risk factors of cancer have been conducted in Afghanistan, WHO reports are the only reliable source for this nation. [5][6][7][8] The Cancer Surveillance Branch (CSU) at the International Agency Estimations were calculated for 38 cancer sites, including other and nonspecific cancers, by sex and 18 predefined age groups. Estimation methodologies and determination of uncertainty intervals continue to rely on the best available data on cancer incidence and death at the national level. The Global Cancer Observatory (GCO) provides interactive tabulation and graphical visualization of the GLOBOCAN data collection for 185 nations and geographical regions by sex. There is a more comprehensive description of regional variability across 20 global areas. 12 To date, no study has published the age-standardized and cancerspecific incidence and death rates in men and women in Afghanistan. Therefore, this article presents an overview of the cancer burden in Afghanistan, including the estimated number of new cancer cases and mortalities by age group in 2020. It also provides 1-, 3-, and 5-year cancer prevalence in Afghanistan and discusses cancer's scale and profile, risk factors for a variety of top five common cancers, and preventative approaches that potentially can decrease future cancer burdens.

| METHODS
The GLOBOCAN 2020 database was used as the primary source of information to obtain data presented in the tables. Data on cancer incidence, death, and prevalence were collected from populationbased cancer registries (PBCR) in Afghanistan. PBCRs provide data on cancer incidence and are crucial for developing and evaluating cancer control programs. Cancer mortality data was collected from the WHO. 10,12 The estimates presented in this study do not con-  Doll and Cook. 13,14 The cumulative risk of developing or experiencing cancer-related death before age 70 was also estimated and given as a percentage.
T A B L E 1 Search strategy terms in selected databases.
The authors did not perform any calculations but used the data provided by GLOBOCAN to create tables that presented the incidence, mortality, and prevalence of cancer in Afghanistan by gender and age groups. The tables were created by combining and revising the data provided in GLOBOCAN to fit the authors' needs.
The use of GLOBOCAN data is free of charge for non-commercial purposes.
The data for this study was obtained from GLOBOCAN 2020 database, and the authors used the available cancer-specific estimates to create tables presenting the incidence, mortality, and prevalence of cancer in Afghanistan by sex and age group. The figures were presented as age-standardized rates (ASR), and the cumulative risk of developing or experiencing cancer-related death before age 70 was estimated and given as a percentage.
In the discussion section, we conducted a literature review to examine the global, regional, and Afghanistan-specific epidemiology, possible risk factors, and prevention and cure measures for the top five cancers in Afghanistan. Our review included peerreviewed articles, policy documents, reports, and guidelines. To gather the necessary information, we employed a search strategy across multiple databases, including PubMed, Scopus, and Google Scholar. We used a combination of keywords, such as "cancer," "epidemiology," "incidence," "mortality," "prevalence," and "Afghanistan" to ensure a broad coverage of relevant literature.
We utilized BOOLEAN operators and MeSH terms to refine our search and increase its specificity (

| Prevalence
In 2020, the most common cancers among Afghanistan's male population were stomach, lung, lip/oral cavity, leukemia, and colorectal, while breast, cervix uteri, stomach, corpus uteri, and ovarian cancers were the most common among women (

| DISCUSSION
According to Global Cancer 2020 statistics for Afghanistan, the five most common cancers are breast, stomach, lung, cervix uteri, and colorectum.
Cervical and colorectal cancers have replaced lip, oral cavity, and esophageal cancers on the list of the five most common cancers as of the 2018 WHO report. 4 Similarly, the five most common cancers worldwide are similar, with breast, lung, colorectum, prostate, and stomach on the list. 15 In addition to the GLOBOCAN report, which provides a global perspective, there is a paucity of comprehensive cancer studies specifically focused on Afghanistan. The limited number of regional and local studies conducted in Afghanistan, [5][6][7][8][16][17][18][19] emphasizes the critical need for further research in this context. Our study aims to address this gap by providing a detailed analysis of the prevalence, incidence, and mortality rates of cancer in Afghanistan. Moreover, we present the latest authentic statistics with epidemiological information on top cancers in Afghanistan, specifically Lung and Colorectum cancer, which have not been previously studied. By comparing our findings with existing studies and discussing the associated risk factors, our research offers a novel contribution to the understanding of cancer epidemiology in Afghanistan.
Afghanistan's inadequate cancer care infrastructure is a major issue due to a lack of data, skilled human resources, and policies and plans. Community awareness of cancer care is minimal, and few organizations have developed strategies to improve it. 18 As a result, screening, prevention, and public education about cancer are critical in Afghanistan where patients must pay for the average cost of cancer treatment (nearly $600000) out of pocket, as there is no proper insurance coverage. 20 Afghanistan's healthcare system is struggling to provide accessible cancer treatment to its population, with only one hospital in Kabul providing free mammography services to the country's 38.9 million residents. 21 Poverty-stricken areas lack medical facilities, making cancer a death sentence for many. Although breast cancer is the most common cancer among Afghan women, there is limited data on cancer incidence and mortality rates in the country. established to improve cancer prevention, diagnosis, treatment, and palliative care services. 22 The program aims to establish cancer registries across Afghanistan to collect data on cancer incidence and mortality rates. Despite limited opportunities for drug and radiotherapy treatments within Afghanistan, the NCCP has been able to establish cancer centers in Kabul, Herat, Mazar-e-Sharif, and Jalalabad. 23 Unfortunately, there are limited opportunities for drug and radiotherapy treatments within Afghanistan. However, some international organizations provide support for cancer patients in the country. For example, the International Atomic Energy Agency (IAEA) provides training for Afghan doctors and nurses on radiation therapy. 24  According to a report by the International Agency for Research on Cancer (IARC), Afghanistan has a lower incidence of cancer compared to other countries. The report states that in 2020, Afghanistan had an age-standardized incidence rate of 108.8 per 100 000 people. 25 There are several reasons why cancer incidence may be low in Afghanistan. One reason could be due to limited data availability and quality. 25 Additionally, Afghanistan has a lower life expectancy compared to other countries, 26 which could contribute to a lower incidence of cancer. However, it is important to note that cancer is still a significant health issue in Afghanistan.

| Breast
Breast cancer (BC) is the most common, often diagnosed, and the leading cause of cancer mortality among the Afghan population, with an estimated 5-year prevalence of 5930 cases, 3173 newly diagnosed cases, and 1783 deaths in 2020 ( Figure 1). BC accounts for around 14.3% (12.5% globally) of all newly diagnosed cancer cases and 11.3% (6.9% globally) of all cancer deaths. It had roughly a 4.5-fold higher incidence rate and a 2-fold higher mortality rate in high-and very high-HDI countries than in low-and medium-HDI countries. 15 BC incidence rates are highest in high-income countries, while BC mortality rates are highest in low-income countries due to inadequate screening and less efficient therapies. 27,28 Breast cancer incidence has continued to rise globally, most likely due to the adoption of increasingly Westernized lifestyles. 29 The combination of multiple factors over several years is the cause of the majority of BCs. Some intrinsic risk factors include female sex, family history, race, genetic mutation, breast tissue density, and past radiation exposure. 30 Obesity, alcohol consumption, smoking, lack of physical exercise, and radiation exposure, on the other hand, are modifiable and preventable risk factors that account for half or more incidences of BC. [31][32][33] In addition, a case-control study found that age at menarche, age at first infant delivery, illiteracy, smoking, and a family history of cancer are significant risk factors for the development of BC in Afghan women. 18 Screening/early detection and active preventive intervention are two main approaches to reducing BC's global burden. 34 Screening methods include mammography, breast self-examination (BSE), and clinical breast examination (CBE). 35 Although mammography screening is also an effective tool, it is not cost-effective in developing countries. 36 Different factors, including demographic characteristics, awareness, literacy, and social and economic situations, might influence BC screening behaviors and should be considered when developing a cost-effective approach to managing BC in Afghan women.
The most viable option for Afghanistan seems to be the BSE, which is more culturally accepted and could be promoted effectively through awareness programs by international health organizations and the public health ministry. 17,37 BC mortality rates vary between countries and regions. In

| Stomach
Stomach or gastric cancer (GC) is Afghanistan's second-most common, frequently diagnosed, and the leading cause of cancer mortality, with a 5-year prevalence of 2913 cases, 2149 newly diagnosed cases, and 1918 deaths in 2020 ( Figure 1). GC account for 9.7% (6% globally) of new cancer cases and 12.1% (7.8% globally) of cancer mortalities in Afghanistan. 15 The GC rates are 2-fold higher in men. In numerous South and Central Asian nations, including Iran, Afghanistan, Turkmenistan, and Kyrgyzstan, it is the most often diagnosed primary cause of cancer in men. 12,40 Risk factors, including Helicobacter pylori, tobacco, genetics, and diet, are known to be involved in causing GC. 33,41 Excessive salt consumption, a lack of fruits and vegetables, preserved foods, and red meat are all dietary factors. 42 Several lifestyle factors have been associated with an increased risk of GC, including high salt intake, smoking, and low consumption of fruits and vegetables. 43 A study by the American Association for Cancer Research confirmed that tobacco smoking moderately increases the risk of developing GC. 44,45 Adenocarcinomas comprise over 90% of gastric malignancies, which usually are caused due to chronic infection of Helicobacter pylori in the body of the stomach. 33 Additionally, two studies in Kabul found a significant positive relationship between the inflammatory potential of the diet, dietary insulin index, and insulin load and the risk of GC in Afghan adults. 46,47 Endoscopy, the gold-standard approach, has resulted in a considerable decline in national screening programs in Japan and South Korea. 48 It is both expensive and invasive, making it an unfavorable option. Instead, genetic and molecular biomarkers are emerging as reliable and non-invasive tools for detecting precancerous lesions and early stages of cancer. 49  This study shows that the GC's incidence is nearly double among men (13.1%) than women (6.7%), which follow the global trend. The age-adjusted incidence rates of GC in men are approximately double those in women worldwide. Some research suggests this is because estrogen, a female hormone, helps protect the stomach from inflammation. 52 Helicobacter pylori infection is closely associated with the development of GC, but the prevalence of infection does not substantially differ by sex. 53 Although, some studies have shown a higher prevalence of H. pylori infection in males in certain regions. 54

| Lung
Lung cancer (LC) is the third most prevalent cancer diagnosed and the leading cause of cancer mortality in Afghanistan, accounting for 1.470 (6.6%) new cases and 1349 (8.5%) deaths in 2020. According to an estimate in 2020, almost 2.2 million new LC cases (11.4%) and 1.8 million cancer deaths (18.2%) occurred worldwide. 15 LC is the leading worldwide cause of cancer morbidity and mortality in males, with men having about twice the rates as women. 55 These rates are also three to four times higher in transitioned countries than in transitioning countries; however, this may change due to the tobacco epidemic since 80% of smokers aged 15 now live in LMICs. 15 Western countries, including Denmark, the United States, and the United Kingdom, which have been linked with the tobacco epidemic since its inception and reached its peak in the middle of the last century, have reduced male LC mortality rates while increasing female LC mortality rates. 56 Several risk factors with possible synergistic effects are associated with LC, including smoking, occupational and environmental risk factors, genetics, and gender, with smoking being the most significant factor in Afghanistan. 33,[57][58][59] While cigarette smoking is the most common form of tobacco consumption, other tobacco products, such as water pipes and smokeless tobacco are becoming widely popular, and their consumption is even increasing among young adults, implying an increase in LC burden shortly. 60 Unfortunately, tobacco products are widely available in Afghanistan, and smoking is socially accepted. 61 Outdoor and occupational exposure to asbestos, radon, polycyclic aromatic hydrocarbons, and arsenic, and indoor air pollution from secondhand smoking, unventilated coal-fueled stoves, and cooking gasses have all been related to LC, especially in Afghanistan. 62,63 Smoking cessation and reducing exposure to indoor pollution are important strategies in the prevention of LC. 64 Extensive tobacco control programs have been effective in decreasing smoking rates, but since total abstinence programs have been considered a failure, combining abstinence programs with tobacco harm reduction programs can help lower smoking rates. 61 Furthermore, implementing strict restrictions on outdoor air pollution and occupational exposure is crucial in Afghanistan. According to the findings of this study, women 15-39 is a higher incidence of LC than older ages. Indoor pollution from traditional stoves in lowincome countries is a significant concern. Studies from Bangladesh and China link exposure to cooking fumes with higher rates of LC in women, despite low smoking rates. 65,66 The WHO cautions that inhaling smoke from polluting household fuels and technologies harms health, especially for women and children engaged in cooking and firewood collection. 67,68 Moreover, young women worldwide have higher rates of LC than men, possibly due to different genetic risk factors such as abnormal genes related to cancer development or impaired DNA repair. 69 Smoking is the leading cause of LC, but exposure to lung disease, occupational hazards, indoor air pollution, and drinking water with arsenic also increases the risk. 70 To address this, public health policies should prioritize smoking cessation, tobacco control programs, and cleaner household fuels/technologies. Cervix cancer is caused by the human papillomavirus (HPV), which is a necessary but not sufficient cause. 33,71 About 70% of all CC cases are caused by two high-risk strains of HPV, 16 and 18. 71 Some sexually transmitted infections (HIV and Chlamydia trachomatis), smoking, a larger number of childbirths, and long-term use of oral contraceptives are also essential cofactors. 72 CC is a largely preventable disease with a decreasing incidence thanks to improved screening and immunization against the most carcinogenic strains of HPV. 73 Completing the prescribed immunization series, standardized screening, and education about contributory variables to urge avoidance of related risks are key preventative activities. Condom usage is around 70% effective in decreasing HPV transmission. 74 The current screening method is Papanicolaou cytology (Pap)

| Cervix uteri
testing. 73 An organized screening program used by developed nations frequently addresses crucial variables for efficient screening. Because of the shortage of healthcare resources in developing countries, they should implement a low-cost/opportunistic screening program. 75 Currently, most low-income countries have ineffective BC screening and poorly documented coverage of CC opportunistic screening (less than 5%). 76 In societies such as Afghanistan, where screening may not be acceptable, primary prevention through HPV vaccination is especially critical. 77 A study in Kabul found that none of the women who developed CC had ever undergone cervical screening or heard of HPV vaccination. 78 According to a cohort study, HPV vaccination in Afghanistan will be cost-effective and beneficial, given the absence of a nationwide screening program for CC. 79 The high incidence of CC among young women in Afghanistan (15-39 years) is a major concern due to the lack of national screening programs and HPV testing, which increases their risk. CC has had a devastating impact on women in Afghanistan, with 1200 new cases and 823 fatalities in 2020. 80 The country ranks 117th in the world for Obesity, physical inactivity, high consumption of red or processed meat, tobacco smoking, and significant alcohol usage are all potentially modifiable risk factors. 33 Therefore, losing body weight, remaining physically active, avoiding smoking, and limiting the intake of red meat and processed foods may assist in preventing this cancer. 82 Because CRC is typically asymptomatic until warning symptoms develop in the late stages, implementing the screening program is critical to lowering cancer incidence and mortality rates. 83 According to some studies, population-based colorectal screening programs are usually not recommended in low-incidence developing nations 84 ; therefore, preventative and awareness campaigns are the most realistic choice.
A high incidence of CRC among young men aged 15-39 years old in Afghanistan has been reported in this study, which is consistent with previous research indicating a rising trend of CRC in young adults in developing countries. 85 The underlying cause of this trend is not clear, but dietary factors may play a role. Specifically, a diet high in red or processed meats is associated with an increased risk of CRC due to the production of carcinogenic compounds during cooking and processing. 86 Furthermore, a diet that is ultra-processed, low in fiber, and high in added sugars has also been linked to a higher risk of CRC. 87 Unfortunately, these dietary factors may be prevalent in many developing countries, including Afghanistan, where cultural and economic barriers can limit access to healthy foods. Afghanistan also has one of the world's highest malnutrition rates.

| Recommendations for cancer prevention in Afghanistan
Cancer is becoming increasingly prevalent in Afghanistan, necessi- ques and madrasas can serve as potential sources of information.
Leveraging the power of social media, television, and radio, with a particular focus on radio due to its popularity in remote parts of Afghanistan, can prove instrumental. In these awareness efforts, the WHO should intensify its collaboration with the Ministry of Public Health (MoPH) in Afghanistan to maximize its impact. By implementing these measures, a more comprehensive approach can be achieved in promoting cancer awareness among Afghan women, thereby improving their health knowledge at this critical time.
Although the proposed recommendations can contribute to reducing the incidence and mortality of cancer in Afghanistan, a comprehensive approach that considers the country's health system and resources is necessary to implement them successfully. Further research is required to better understand the epidemiology of cancer in Afghanistan and develop region-specific policies to prevent and control the disease. Urgent action is required to address the growing cancer burden in Afghanistan.

| Limitation
GLOBOCAN collects cancer data using various methods depending on data availability, which affects the accuracy of its estimates. The validity and quantity of data vary from accurate counts to estimations based on sampling or nearby rates. A scoring system rates the quality and accuracy of the estimates, enabling users to evaluate countryspecific data. However, data quality and availability are improving over time owing to cancer incidence and mortality registry initiatives.
Despite these limitations, the GLOBOCAN 2020 estimates are the most reliable cancer data and provide a credible basis for prioritizing cancer management globally.

| CONCLUSION
Afghanistan is in an epidemiologic transition stage, and the burden of cancer is expected to rise due to population growth and aging, as well as a lack of adequate strategies to prevent, diagnose, and treat diseases, especially non-communicable diseases, such as cancers. Analysis of the top five cancers, including breast, stomach, lung, cervix uteri, and colorectum, highlights the urgent need for improved health- implications, this study serves as a valuable resource for policymakers, healthcare providers, and international organizations working toward enhancing cancer prevention and control efforts in Afghanistan.

ACKNOWLEDGMENTS
The authors wish to express their gratitude to GLOBOCAN for its publicly available cancer database system that provides valuable insights into cancer in various countries.

FUNDING INFORMATION
No funding was received for this study.