Mr. Speaker, I appreciate the opportunity to speak to private member's Motion No. 235.
As many of the speakers have noted, it is next to impossible for any of us not to have had personal experience with members of our family being diagnosed with cancer and having to work through those issues. I am no different; my father suffers from it right now. All of us should commend the member for putting forward this motion which starts to at least pay attention to some of the issues that we need to address with respect to this disease. I am pleased to have the opportunity to speak in support of this extremely important motion.
Each year in Canada over 200 children and youth under 20 years of age are diagnosed with a malignant brain tumour and nearly 60 die from their disease. Brain tumours are the most common solid tumour in children and youth and account for approximately one-fifth of all cancers diagnosed and 25% of all children's cancer deaths.
Depending on the age of the child and the type of tumour, between 20% and 80% of children or adolescents diagnosed with a brain tumour survive. For all tumour types and ages combined, the survival rate is 67%. Among children or adolescents who survive, the long term health and functioning consequences are serious.
The annual incidence rate of brain tumours in children and adolescents has remained consistent over the past 20 years with an average of 30 cases per million children under 20 years of age. The annual incidence rate of brain tumours is highest in children from zero to seven years of age, which is 35 cases per million children. The rate then drops and stays consistent from older childhood until early adolescence, which is 21 per million. After the age of 18, the incidence of brain tumours declines again.
Brain tumours in children differ significantly from adult brain tumours in their site of origin, histological features, clinical presentation, and tendency to spread early in the disease history to other parts of the nervous system. Brain tumours are nearly 25% more common in boys than in girls. Most childhood brain tumours arise in the supporting cells of the brain.
PNETs arise from undeveloped brain cells, which are primitive nerve cells, and are most common in the cerebrum part of the brain. PNETs are fast growing tumours and are highly malignant. Very often these tumours have spread within the central nervous system even before diagnosis.
Ependymomas arise from the cells that line the internal surfaces of the brain in the cerebral hemispheres. These tumours are most common among younger children and are often benign.
PNET and ependymoma tumours are most commonly found in children under five years of age. From ages five to nine, other types of tumours are more common.
Survival is lowest for infants diagnosed with a brain tumour under a year of age. In particular, only 20% of infants with a PNET are expected to survive. Survival increases with increasing age at diagnosis.
Children one to four years of age have a 59% survival rate, which increases to 64% in children five to nine years of age, 70% in pre-teens 10 to 14 years of age, and 77% in adolescents 15 to 19 years of age. Children and adolescents diagnosed will have the highest survival rate.
The incidence of brain tumours is higher in male children, children exposed to cranial ionizing radiation, and children with specific congenital anomalies such as neurofibromatosis. However, no single risk factor has been identified that accounts for a larger proportion of brain tumours found in children or adolescents.
Initial symptoms of childhood brain tumours include headaches and vomiting. These symptoms are then accompanied by seizures, dizziness, weakness, gait disturbance, and visual problems. Brain tumours are often diagnosed with a CAT scan, an MRI or a PET scan, which is followed by a biopsy for histological typing and confirmation. Steroids are often given as the first line of therapy to help ease the swelling of the brain. If possible, the tumour is then removed by surgical resection. Malignant tumours often require radiation therapy and/or chemotherapy in addition to surgery.
It is estimated that up to 50% of all childhood tumours in the brain are benign, meaning they are slow growing and they rarely spread, in contrast to malignant tumours that are fast growing and invasive.
Some benign brain tumours have well-defined borders so removal is relatively easy. However, when located in a vital area of the brain, a benign tumour can be life threatening.
Some malignant brain tumours can have a benign clinical natural history, meaning they often start as benign and become malignant over time.
Brain tumours, whether malignant or benign, produce clinical effects of similar mechanisms of mass effect, hemorrhage, seizure and edema.
Data on benign brain tumours is not routinely collected by the provincial and territorial cancer registries in Canada. Some registries include benign brain tumours, while others simply do not. The Canadian Cancer Registry does not include data on benign brain tumours as it cannot be consistently collected across the country.
As benign brain tumours are not included in the Canadian Cancer Registry and are only included in some provincial cancer registries, we cannot accurately determine the national incidence or survival rate of children and adolescents diagnosed with a benign brain tumour in Canada in the way that we can for malignant tumours.
This lack of reporting is leading to an underestimation of the burden of brain tumours on Canadians and the Canadian health care system since up to 50% of benign tumours are not included. Though not malignant, benign brain tumours can cause serious disruption in normal function, especially among children whose brains are rapidly developing.
Unlike tumours in other areas of the body, tumours in the brain develop within a confined space where even a small growth can seriously affect normal brain function. The clinical effects of a brain tumour are similar regardless of whether they are benign or malignant due to their location.
In addition to the increased risk of death and/or loss of cognitive and neurological functioning, clinical manifestations of benign brain tumours include developmental delays, endocrine disorders, seizures, visual impairment, an increase in pressure on the brain, severe headaches, vomiting, ataxia and loss of balance.
In contrast to malignant brain tumours, the incidence of benign brain tumours increases with age. They are most common among older adolescents. Benign brain tumours are also more common in girls and adolescents, as opposed to malignant brain tumours that are found more often in boys.
While malignant tumours are most common in the infratentorial region of the brain, which is the bottom portion consisting of the cerebellum and brain stem, benign brain tumours are most common in the sellar region, a depression of the bone at the base of the skull.
The primary treatment for benign brain tumours is surgical resection, which can often be difficult depending on the location of the tumour. Incomplete resection can lead to tumour recurrence. Some children with benign brain tumours also receive cranial radiation.
Cancer therapy often produces adverse long term health outcomes that can manifest in months to years after completion of treatment and are commonly referred to as late effects. Young children in particular are at risk of significant neurological and cognitive sequelae despite the therapy they receive.
Survivors of benign brain tumours are often left with long term disabilities from both the disease and the treatment received.
Our knowledge of these tumours is limited without including them in a national registry such as the Canadian Cancer Registry. We cannot accurately estimate incidence or outcome and therefore, we cannot estimate the burden on Canadians or the Canadian health care system.
Because brain tumours cause disruption in normal function similar to that caused by malignant brain tumours, and because the location of a brain tumour is as important as its behaviour for morbidity and mortality, all cancer registries in the U.S. began to include benign brain tumours in their registries starting in 2004. Canadian provincial and territorial registries should also begin to collect data on benign brain tumours.
Michael Vandendool, a young boy in my daughter's class, is suffering from cancer at 10 years old. The opportunity for us to at least start to repair and begin work on the registry will help all.