Can childhood cancer be prevented — or screened for?

Where childhood cancer comes from — Unlike many adult cancers, which develop over decades in response to accumulated environmental exposures (tobacco smoke, UV radiation, alcohol), most childhood cancers arise from genetic changes that happen very early in development — sometimes before birth, as cells divide rapidly. These are sporadic mutations, meaning they happen without any predictable cause. They are not inherited in most cases, and they are not triggered by the child's or parent's behaviour.

Why there is no "prevent cancer in kids" checklist — Because the biology is different, the prevention strategies that work for adults do not translate to children. No food, supplement, or activity has been shown to meaningfully reduce a child's risk of developing cancer. Advice you may see online about "anti-cancer diets for children" or specific supplements is not supported by clinical evidence and should not be acted on without medical guidance.

The role of hereditary risk — A small proportion of childhood cancers — roughly 5 to 10 percent — are associated with inherited changes in genes such as TP53, RB1, WT1, or others linked to recognised cancer syndromes (Li-Fraumeni syndrome, hereditary retinoblastoma, Beckwith-Wiedemann syndrome, and a few others). If your family has a pattern of childhood cancers across generations, or if your child has been diagnosed with a cancer type known to have a hereditary form, a referral to a cancer genetics specialist is appropriate. For these families, genetic counselling can clarify what the risk means in practical terms and whether surveillance is recommended.

What parents can do — Because childhood cancer cannot be routinely prevented or screened for, the single most useful action is knowing the warning signs — and acting on them promptly rather than waiting. Early referral to a paediatric oncologist, when a symptom genuinely warrants investigation, gives the best chance for timely diagnosis. That is not prevention, but it is the most impactful thing a parent can do. The CION Cancer Clinics team is here to evaluate any concern clearly, without rushed judgments or unnecessary investigations.

Lumps or swellings — A lump anywhere on the body that has been present for two to three weeks without shrinking, or that is growing, should be evaluated. Lymph node swelling that persists beyond this window — particularly if it is painless, firm, and not associated with any obvious infection — warrants investigation.

Unexplained pallor, fatigue, or easy bruising — These are common presentations of leukaemia, which is the most common childhood cancer. If your child looks unusually pale, has far less energy than expected for their age, or bruises more easily than normal, a full blood count is a reasonable first step.

Persistent fever without obvious cause — A fever lasting more than two weeks that does not respond fully to treatment for a common infection, or that recurs without clear explanation, should prompt further investigation including a blood count.

A white or yellow glow in the pupil — If you notice a white or yellow-white reflection from one or both pupils in photographs — particularly flash photos taken straight on — show the photos to your doctor. This glow, called leukocoria, can be an early sign of retinoblastoma and warrants prompt ophthalmological evaluation.

Bone or joint pain at night — Limb pain that reliably wakes a child at night, is not explained by injury or growing pains, and does not resolve with rest should be assessed. Night pain specifically is a feature worth reporting to a doctor because it is less typical of benign musculoskeletal causes.

Early morning headaches with vomiting — Headaches that are worst on waking and accompanied by vomiting — particularly in a child who then improves as the day goes on — may reflect raised pressure inside the skull and warrant neurological assessment.

Unexplained weight loss or appetite change — A persistent, unexplained loss of weight or a prolonged change in appetite in a child who is not going through an obvious growth phase or illness is worth raising with a paediatrician.

Vision changes, squint, or drooping eyelid — New-onset squint (especially in a child over six months old who was previously tracking normally), vision changes reported by the child, or a drooping eyelid (ptosis) should be evaluated by a doctor or ophthalmologist.

Most children with any of these symptoms will have a reassuring, non-cancer explanation. But the right response is always prompt evaluation — not waiting and hoping it will pass. If you are concerned, you deserve a clear answer.