By Dr Meneka Kumaran
A man in his early forties once completed a routine health screening and, after hearing that the results were normal, expressed relief that cancer was no longer a concern for the next few years. This reaction is common and understandable. A normal report feels reassuring, almost like a reset. However, a clear screening does not eliminate risk. It indicates only that disease has not yet crossed a detectable threshold.
Cancer rarely begins abruptly. It develops gradually, shaped by biological conditions that exist long before symptoms appear. By the time a lump becomes palpable or pain develops, abnormal cellular behaviour has often been present for years.
What A Screening Actually Shows
During a health screening, the focus is not only on identifying tumours but on recognising early biological signals.
- The weight that has gradually increased over time.
- The fatty liver discovered incidentally on ultrasound.
- The fasting glucose level that has not reached diabetes but is trending upward.
Individually, these findings appear minor. Collectively, they describe a metabolic environment. Persistent low-grade inflammation, insulin resistance and excess visceral fat create conditions that allow damaged cells to survive longer than they should. Over time, this increases the probability of mutations accumulating.
The same physiology that contributes to heart disease also influences cancer formation. Breast, colorectal, pancreatic and endometrial cancers are increasingly associated with metabolic syndrome rather than hereditary factors alone.
Although cancer is often attributed to genetics, a substantial proportion is linked to modifiable risk factors. Globally, approximately 30–50% of cancers are preventable through reduction of tobacco exposure, maintenance of healthy weight, physical activity and dietary control (World Health Organization). Prevention therefore occurs long before diagnosis, often before any abnormality is visible on imaging.
The Prevention That Is Often Overlooked
Vaccination remains one of the most effective cancer prevention strategies available, yet adult uptake remains low.
Human papillomavirus (HPV) vaccination prevents most cervical cancers and reduces risk of several anogenital and oropharyngeal cancers (Centers for Disease Control and Prevention). Hepatitis B immunisation protects against chronic infection that may eventually progress to liver cancer, which remains prevalent across Asia.
Unlike screening, vaccination acts upstream in the disease pathway. Screening detects abnormal growth. Immunisation removes the initiating cause.
From a public health perspective, this distinction is important: treating cancer requires complex therapy, but preventing infection removes the biological trigger decades earlier.
Why Normal Results Still Matter
Patients frequently question the need for continued follow-up after a normal result.
Cancer risk is determined not by a single measurement but by trajectory. A normal mammogram today does not eliminate future risk. A clear colorectal screening does not reverse long-standing metabolic strain. A stable tumour marker does not guarantee long-term stability if underlying risk factors persist.
Screening functions as monitoring, identifying deviation early enough to intervene before structural disease develops.
In many cases, the most meaningful findings are not abnormal values but borderline trends. Addressing these early can prevent both cardiovascular disease and malignancy later in life.
The Nature Of Long-Term Protection
Long-term health rarely results from sudden dramatic change. It is typically the consequence of sustained behaviours: weight stability, regular movement, tobacco avoidance and adherence to follow-up evaluation even in the absence of symptoms.
Cancer develops slowly, and protection develops similarly.
A screening report is not proof of safety but an opportunity, a point at which the biological direction can still be altered.
The most effective cancer strategy is not early detection.
It is preventing the disease from forming at all.
