Two-thirds of adults are unsure whether they can detect early signs of cancer in children, study finds.
And only one in ten people experience some of the more subtle symptoms.
Researchers based at the University of Nottingham and childhood cancer charities surveyed 1,000 adults about their effectiveness in detecting 42 classic signs of childhood cancer.
On average, participants – including parents – recognized only 11 in total.
Just under half were aware that lumps or swellings in the pelvis, breast or testicles were potential symptoms of cancer.
This chart highlights some of the lesser known signs of childhood cancer, including early or late puberty, developmental delays, slow growth, slow recovery from bone injuries, limited or abnormal facial movements and hearing problems.
Blood in urine or stool (44 percent), changes in moles (43 percent) and weight loss (40 percent) were other recognized signs.
All are also markers of disease in adults.
But much more subtle signs, including some specific to childhood cancers, were barely known.
Only 10 percent of adults recognized early or late puberty as a potential sign of cancer.
Puberty is determined by changes in hormone production. Tumors can disrupt the process, speeding it up or slowing it down.
The average age for girls to start puberty is 11, while for boys it is 12. Although it can start as early as the age of eight.
Another sign of cancer that might go unnoticed in young children is developmental delays, with only 11 percent of adults aware that this could be a sign of the disease.
This is when babies fail to reach developmental milestones such as the ability to walk, crawl, or control motor skills with their hands after a certain number of months of life.
Other subtle signs of cancer included slow recovery after a bone injury like a broken arm, with only 14 percent of those surveyed recognizing this.
The authors of the report published their findings in the journal Archives of childhood illnesses.
Other potential cancer symptoms on the list included those that could be confused with a host of other childhood illnesses, like fever or difficulty swallowing.
The authors said their findings showed the need for an education campaign about the signs of childhood cancers.
“Awareness raising has been seen as a key strategy for early cancer diagnosis in the UK, but little attention has been given to childhood cancers,” they wrote.
“The perceived rarity of childhood cancer poses a major barrier to early diagnosis.
“Although the number of cases may be small compared to adult cancers, the cumulative risk from birth to early adulthood is comparable to that of other childhood diseases.”
“This needs to be communicated to the public, because parents usually associate common symptoms with common childhood illnesses, but not with cancer.”
They added that because childhood cancer symptoms can often mimic common conditions, public awareness of the signs could be key to detecting cases early, when they are most treatable.
Childhood cancer is the leading cause of death in children aged over 12 months in the UK and a major cause of acquired disability in young people.
An estimated 1,800 new cases of cancer are diagnosed in children in the UK each year, with 250 deaths.
NHS figures on cancer waiting times showed that just six in ten (62.6%) cancer patients were seen within the two month time frame. NHS guidelines say 85 per cent of cancer patients should be seen within this time frame. This objective has not been achieved nationally since December 2015
Survival varies greatly depending on the type of cancer. Overall, 84 percent are still alive five years after diagnosis.
In the United States, the numbers are much higher, with 15,000 cases of cancer in people under the age of 20 each year.
It should be noted that many of the potential cancer symptoms on the list of 42 could also be caused by a number of less serious conditions and illnesses.
The study authors said their study had some potential limitations.
As in other surveys, volunteers may have been tempted to give answers they thought the researchers wanted to hear, rather than a true reflection of their own knowledge.
The researchers also acknowledged that their sample of 1,000 adults did not include many people from younger demographic groups.
The 42 signs of cancer in children and what percentage of adults recognized them
Lump/swelling of the pelvis, testicles or breast: 46 percent
Blood in urine or stool: 44 percent
Changes in moles: 43 percent
Chest wall or armpit lump/swelling: 41 percent
Weight loss: 40 percent
Abdominal distension/mass: 38 percent
Lump/swelling in face, jaw and skull: 36 percent
Persistent/recurring headache: 32 percent
Fatigue or persistent/recurrent fatigue: 32 percent
Loss of appetite: 31 percent
Persistent vomiting: 31 percent
Excessive bleeding/bruising/rash/petechiae (a type of rash): 30 percent
Convulsions or seizures: 29 percent
Pain in the chest wall or armpits: 29 percent
Unexplained swelling of bones or joints: 27 percent
A change in bowel habits – constipation or diarrhea: 27 percent
Persistent/recurring/progressive abdominal pain or discomfort: 26 percent
Difficulty urinating: 26 percent
Vision problems: 26 percent
Swollen glands: 26 percent
Deterioration in balance, walking and speaking: 23 percent
Persistent/recurring pain in bones or joints, worse at night: 23 percent
Noticeable paleness of the skin: 22 percent
Multiple infections or flu-like symptoms: 22 percent
Unexplained bleeding after sex and between periods: 22 percent
Fever and night sweats: 21 percent
Shortness of breath: 21 percent
Difficulty swallowing: 21 percent
Lameness or unexplained weakness: 20 percent
Persistent/recurring unexplained cries in young children: 19 percent
Persistent/recurring sore throat or hoarse voice: 18 percent
Torticollis/head tilt or neck stiffness in young children: 18 percent
Leukocoria: 18 percent
Hearing loss: 17 percent
Abnormal eye movements: 17 percent
Abnormal facial movements: 16 percent
Persistent earache: 16 percent
Limited mouth opening: 14 percent
Slow recovery after bone or joint injury: 14 percent
Slow growth: 13 percent
Developmental delay in young children under two years old: 11 percent
Early or late puberty: 10 percent