Gastrointestinal (GI) cancers—gastric, oesophageal, and colorectal cancers—are a severe and growing public health problem in Sri Lanka, driven by genetic predisposition as well as a complex interaction of lifestyle and environmental risk factors. Food quality is the strongest modifiable risk factor determining both disease occurrence and disease outcome among them. The following broader critical overview sets out the epidemiological patterns, main etiologic determinants, and complex interaction between diet and risk for GI cancer, with reference to Sri Lanka’s unique context.
Epidemiological Trends in Sri Lanka
Incidence rates of GI cancers increased significantly in Sri Lanka over the last two decades. Gastric cancer incidence increased exponentially from 2001 to 2012, with exponentially increasing rates in old age groups and females, possibly owing to lifestyle changes and increased reporting. Colorectal cancer is among the top five cancers in the country, with more than 1,500 new cases every year until 2020, with very high rates of incidence among adults aged more than 60 years. Oesophageal cancer is also on the rise, with excellent male predominance and poor overall survival rates, largely as a result of late diagnosis.
Age and Gender Patterns
Age is an absolute risk factor, with the majority being more than 40 years old, with the peak being above the age of 60. The males are worst hit by oesophageal and colorectal cancer, while gastric cancer still rises in females due to changed exposures or underlying genetic predispositions.
Principal Etiological Factors
Causation of GI cancer in Sri Lanka is especially multi-factorial:
Infectious Factors Helicobacter pylori infection is confirmed in Sri Lankan patients with gastric cancer and results in chronic inflammation and mucosal change, ultimately resulting in malignancy.
The gut microbiota is also being faulted increasingly, with recent evidence indicating microbial community changes to have an effect on colorectal carcinogenesis, particularly with dietary fibre intake and dietary exposure to processed foods.
Genetic and Family History
Family history of genetic factors, especially of colorectal cancer, is riskier by virtue of heritable genetic mutations (e.g., APC, MLH1/2/6 genes) and polygenic susceptibility.
Inherited genetic syndromes such as Lynch syndrome and familial adenomatous polyposis are implicated but underdiagnosed.
Lifestyle and Environmental Exposures
- Smoking tobacco and chewing betel are prevalent habits in Sri Lanka, exposing oral and upper GI mucosa to carcinogens and causing chronic irritation.
- Alcohol consumption adds to the risk, particularly in oesophageal and colorectal cancer, often in combination with tobacco.
- Workplace exposure to pesticides, particularly among rural farm labourers, has been associated with heightened incidence of GI cancer, challenging agrochemical safety standards.
- Water pollution and food safety risks, including mycotoxin or arsenic contamination, may also contribute to cancer risk among vulnerable populations.
Dietary Factors
Diet quality is a central modifiable risk factor for all the primary GI cancers:
High-Risk Practices
- Heavy intake of processed meats—especially sausages, bacon, and canned meat—exposes individuals to nitrosamines, which increase the risk of colorectal cancer.
- Fried and charred foods—usually consumed due to cultural food cooking habits—contain individual polycyclic hydrocarbons and burned oils, known GI carcinogens.
- Increased salt and pickled food are closely associated with gastric cancer development by enhancing mucosal damage and facilitating carcinogenesis.
Protective Dietary Patterns
- High intake of dietary fibre from intact vegetables and grains promotes positive changes in gut flora, speeds bowel movement, and reduces the time of contact between carcinogens and the GI tract.
- Regular intake of fruits and vegetables supplies antioxidants and bioactive substances that counteract free radicals and reduce DNA damage, thus reducing the risk of GI cancer.
- Mediterranean or DASH diet compliance—characterised by decreased processed food consumption and greater whole food and plant consumption—is quantifiably associated with GI cancer risk reduction in Asian populations.
Socioeconomic Impact on Food Quality
Urbanization, income disparities, and globalization have steered food patterns in Sri Lanka towards increased consumption of processed foods and away from traditional high-nutrient whole grain-based diets with legumes and fresh fruits and vegetables. National surveys indicate that more than 70% of Sri Lankan adults currently consume beyond the recommended intake of fruits and vegetables, particularly having a significant effect on urban communities.
Diet Quality and Associations with GI Cancer Outcomes
Case-control and international and regional cohort studies make a direct association with poor diet quality and high incidence of GI cancer:
For each one standard deviation increase in healthy diet ratings (e.g., high fiber, low red/processed meat, high fruit/vegetable intake), there is approximately a 12–17% reduced risk for GI cancers.
Malnutrition is very prevalent in diagnosed patients, over half of whom are moderately or severely nutritionally disadvantaged, with a survival and treatment outcome effect.
Nutritional deficiencies are linked with less favourable treatment results and quality of life, as in most Sri Lankan patient populations.
Cancer Treatment and Diet
Effective control of cancer depends on optimum nutritional status. Multidisciplinary practice and minimal access surgery procedures are increasingly applied in Sri Lankan hospitals, but still upper GI cancer outcomes remain worse than global, predominantly because the cancers present late and are complicated by occult malnutrition. Nutritional assessment and treatment are useful additions to ongoing care.
Prevention Strategies and Public Health Implications
Public health action is indicated with these results:
- Training and publicity campaigns at the national level among school-going children and high-risk groups to improve food habits should be undertaken.
- Improvement in food safety and quality of water and regulation of agrochemical use can also avoid further exposure to environmental risk.
- Expanded screening for the population for colorectal and stomach cancer, particularly in individuals over 40 years and with a history of familial occurrence, would facilitate early detection and better prognosis.
- Compliance with evidence-based dietary standards, e.g., those recommended by Sri Lanka’s Ministry of Health, is crucial. These prefer increased intake of whole foods (kurakkan, red rice), leafy green vegetables (gotukola, mukunuwenna), and locally grown fruit and decreased intake of blackened and processed items.
Conclusion
The burden of gastrointestinal cancers is rising in Sri Lanka from a complex combination of genetic, lifestyle, and environmental factors, with dietary quality playing a major role in both incidence and disease progression. Prevention of dietary risk factors by public health policy, individual education, and community mobilisation—coupled with increased screening and cancer care infrastructure—is perhaps the most crucial strategy in reducing the national cancer burden. Prevention of straying from traditional diets rich in plant foods, limitation of consumption of processed and carcinogenic foods, improved access to clean water and nutrition knowledge, and increasing physical activity levels can significantly decrease risk and outcome disparities.
References
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- De Zoysa IM et al. Risk factors for colorectal carcinoma; a hospital-based study. 2024.
- Department of Health Sri Lanka. Dietary Guidelines – Nutrition Therapy for Specific Diseases. 2020.
- Durdans Hospital. Colorectal Cancer is Curable in Sri Lanka. 2024.
- FAO. Food-based dietary guidelines for Sri Lanka. 2020.
- Jayarajah U et al. The incidence and patterns of gastric cancers in Sri Lanka from 2001 to 2012. Wiley. 2020.
- Moazzen S et al. Diet quality indices and gastrointestinal cancer risk. PMC. 2021.
- Namaki M et al. Diet quality and upper GI cancer risk, Golestan Cohort Study. PubMed. 2023.
- Nutritional Status & Quality of Life among GI cancer patients in Southern Sri Lanka. JNFS. 2021.
- Parkway Cancer Centre. Stomach (Gastric) Cancer: Signs, Diagnosis & Treatment. 2024.
- Samarakoon Y et al. Preventing colorectal cancer in Sri Lanka. JCCPSL. 2020.
- Sri Lanka Ministry of Health. National Guideline on Early Detection and Referral Pathways. 2020.
- Wijeratne DT et al. Colorectal Cancer Treatment Characteristics and Outcomes in Sri Lanka. ASCO. 2022.
- Wijesekera S et al. Outcomes of patients with esophageal and gastric cancer in Sri Lanka. PubMed. 2023.
