Cancer in Adolescents in Canada (15-19 years)
Table of Contents
List of Figures
- Figure 1 : Age-standardised incidence rates (ASIR, 1992-2007) and age-standardised mortality rates (ASMR, 1992-2006) for all cancers among adolescents, 15-19 years, Canada
- Each year, on average 412 adolescents are
diagnosed with cancer in Canada and 74 die
from the disease.,
- Although the proportion of adolescents diagnosed
with cancer is small compared to older individuals,
a diagnosis of cancer during adolescence can
have long-term impacts on life expectancy and
quality of life.
- The most common types of cancers in adolescents
include lymphomas (29%), carcinomas (20%), germ
cell tumours (13%), and leukemias (12%). Nine out
of ten lymphoma diagnoses are represented by
Hodgkin and Non-Hodgkin lymphoma, and nearly
three quarters of carcinomas and other malignant
epithelial neoplasms are thyroid carcinomas or
malignant melanomas. Among younger children,
embryonal tumours such as neuroblastoma, rhabdo-myosarcoma, Wilms tumours, hepatoblastoma, and
retinoblastoma are more common. ,
- Adolescents with cancer have not demonstrated
the same gains in survival experienced by younger
children. It is not clear why this outcome gap exists.
Lower rates of enrolment in clinical trials among the
former may partially explain this phenomenon.
Incidence and Mortality
- Between 1992 and 2007, the incidence of
adolescent cancer remained stable (Figure 1)
and the average age-standardised incidence
rate (ASIR) was observed to be 199 cases per
- Differences by sex were evident. More males
were diagnosed with cancer than females during
this period (3530 versus 3073). Thyroid cancer
was the most common cancer among females,
representing 19% of all diagnoses per year. Germ
cell tumours of the testis was the most common
cancer among males, representing 24% of all
diagnoses per year.
- Overall age-standardized cancer mortality rate
for adolescents declined significantly between
1992 and 2006, by 3.0% per year. For the same
period, the average age-standardised mortality
rate (ASMR) was observed to be 36 cases per
- Leukemia is the most common cause of cancer
deaths in both sexes (30% in males, and 24% in
females), followed by brain and nervous system
cancers (15% in males and females).
Figure 1: Age-standardised incidence rates (ASIR, 1992-2007) and age-standardised mortality rates (ASMR, 1992-2006) for all cancers among adolescents, 15-19 years, Canada
[Click to enlarge]
[Figure 1, Text Equivalent]
Source: The Canadian Cancer Registry and the Canadian Vital Statistics
Death Database, Statistics Canada.
- As in younger children, little is known about the
causes of cancer among adolescents. While
prenatal and congenital factors play a stronger role
in the aetiology of cancers in younger children,
environmental risk factors are more likely to be
implicated in adolescent cancers. However, very few
are linked to a single risk factor. Exceptions consist of
carcinogens such as diethylstilbestrol, associated with
vaginal or cervical adenocarcinoma, and exposure to
ionizing radiation, including radiation-induced cancer
therapy. Other suspected environmental carcinogens
include excessive exposure to sunlight, and smoking
tobacco products. Scientific evidence suggests that
adolescents who develop cancer after prolonged
exposure to an environmental carcinogen may have
a predisposing genotype.
- Adolescents diagnosed with cancer in Canada
are commonly treated with a combination of
chemotherapy, radiotherapy, and surgery.
- Approximately 30% of adolescents are treated at
17 pediatric cancer centres across the country,
with variation by region, type, and age at diagnosis.
The rest are treated at adult cancer centres.
- There are clear advantages of being treated at a
specialised pediatric cancer center. Between 1995
and 2000 adolescents treated at a pediatric cancer
centre in Canada were more likely to be enrolled in
a clinical trial (21% versus 0%) and have shorter wait
times until treatment (92 days versus 57 days) than
those treated at an adult centre.
- Enrolment in clinical trials offers a survival advantage for
certain pediatric cancers such as acute lymphoblastic
leukemia, non-Hodgkin lymphoma, Wilms tumours, and
medulloblastoma, with some emerging evidence for
rhabdomyosarcoma. The secondary benefits of clinical
trial participation are improved quality of life due to
care from an expanded healthcare team, individualised
treatment protocols, and opportunities to contribute to the
care of future patients.
- The latest Canadian statistics on advances in the
treatment show that 85% of adolescents and young
adults (15-29 years, excluding Quebec) will survive
five years past their diagnosis. Some cancers in
this age group have better prognosis than others.
Among common cancers, the highest five-year survival
proportions were observed for thyroid (99%), testis
(96%), Hodgkin lymphoma (95%), and melanoma
(93%), while the lowest were seen for leukemias (68%)
and brain tumours (68%).
- Treatment and care for adolescents remains a
challenge due to low participation in clinical trials,
the type of tumours in this age group, patterns of care,
and the lack of specialised cancer care centres for
adolescents in Canada.
- Although children and adolescents are more likely
to survive cancer when compared to adults, due to
the adverse effects of cancer treatments they receive,
approximately two-thirds experience poor health
outcomes later in life known as late effects.
- Some of these adverse effects of treatment include
cardiopulmonary, endocrine, renal or hepatic
dysfunctions; female infertility; male gonadal toxicity;
neurocognitive impairment; psychosocial difficulties and
the development of subsequent cancers. ,
- The complexity of psychosocial and educational needs
in adolescent survivors of cancers is addressed in a
few Canadian pediatric cancer centres. The rarity of
the conditions and the lack of research into the unique
needs faced by survivors make it difficult to offer longterm survivorship care.,
Formerly known as the Canadian Childhood Cancer
Surveillance and Control Program, the Cancer in Young
People in Canada Program (CYP-C) aims to fill gaps
in knowledge and ultimately reduce the burden of
childhood cancer in Canada. CYP-C is a partnership
between the Public Health Agency of Canada and the
C17 Council, a network of all the seventeen pediatric
cancer centers across the country. For more information,
please contact the manager of the CYP-C program at