Cancer symptoms by age in children — what to watch for at every stage

Different cancers have peak incidence at different ages because the cells most likely to become cancerous change as the body grows. Retinoblastoma affects the developing retina and is almost exclusively a disease of infants and toddlers under 5. Neuroblastoma arises from immature nerve cells and is most common in children under 5. Leukemia can occur at any age but peaks between 2 and 8. Bone cancers like osteosarcoma and Ewing sarcoma are most common in teenagers during the rapid growth spurt of puberty. Because each cancer targets a different cell type and age group, the visible warning signs also look different. A parent who knows the age-specific pattern is better placed to notice something that needs medical attention.

A white glow visible in a baby's eye in flash photographs — called leukocoria — is the most commonly recognised early sign of retinoblastoma, a cancer of the retina. However, leukocoria can also be caused by a cataract, a retinal detachment, or certain eye infections. It is never normal, and any white reflection visible in the pupil should be reviewed by a paediatric ophthalmologist promptly — ideally within days, not weeks. If retinoblastoma is found early, treatment preserves both vision and life in the great majority of cases. The key message is not to wait for a second opinion from family: get it checked.

An abdominal lump in a young child should always be evaluated promptly by a paediatrician or paediatric oncologist, but it does not automatically mean cancer. Many causes — including a distended bladder, enlarged lymph nodes, or an organomegaly from a viral infection — are benign. That said, the two most important cancers that present as an abdominal mass in children under 5 are Wilms tumour (nephroblastoma, arising from the kidney) and neuroblastoma (arising from the adrenal gland or along the spine). Both are treatable when found early. Your doctor will order an ultrasound as the first step; further tests follow depending on the findings. Do not delay the evaluation.

Bone or joint pain and unexplained tiredness in a school-age child are among the most common symptoms of leukemia, but they are also very common in healthy children — from growing pains, sports injuries, or viral illnesses. The features that raise concern are: pain that is persistent for more than two to four weeks, pain that wakes the child at night, pain that is not explained by any injury or exercise, and tiredness that does not improve with rest or sleep. If these symptoms come together with paleness, easy bruising, petechiae (tiny red spots on the skin), or unexplained fever, a complete blood count (CBC) should be done urgently. This simple blood test usually reveals whether further investigation is needed.

Yes, adolescents develop cancer, though far less often than adults. Cancers that are more common in teenagers than in younger children include Hodgkin lymphoma, osteosarcoma and Ewing sarcoma (bone cancers), testicular cancer in teenage boys, and thyroid cancer. Teen cancer signs to watch for include: a painless lump or swelling in the neck, armpit, or groin that does not go away; persistent deep bone pain — especially in a limb — that is worse at night; unexplained weight loss of more than a few kilograms over a few weeks; prolonged fatigue that does not improve with rest; and in boys, a painless lump or change in texture within one testicle. Most of these symptoms will have a benign cause, but any that persist for more than two to three weeks should be assessed by a doctor.

Speed matters. If you notice a combination of two or more warning signs — for example, persistent fever with paleness and easy bruising, or a new abdominal lump with loss of appetite — do not wait to see if it resolves on its own. Arrange a paediatric appointment within days. For specific signs such as a white glow in the eye or a firm abdominal mass, the evaluation should happen within 24 to 48 hours. Early-stage childhood cancers, detected before they spread, generally have significantly better outcomes than those caught at an advanced stage. At CION Cancer Clinics, we offer a free first consultation for all cancer patients, and our 45-minute appointments are designed to give you enough time to describe everything you have noticed without feeling rushed.