Larry F. Ellison

Canadian cancer statistics at a glance: cancer in children

1The incidence is generally highest during the first 5 years of life and decreases with age. The incidence rates of the most common childhood cancers have remained stable during the past 2 decades (Figure 1). The rate of death from childhood cancer has decreased substantially but is still about 135 deaths each year (24.6 per million in 2004). 1 Survivors of childhood cancer are at substantial risk for health problems, including late sequelae of cancer treatment and chronic psychological and cognitive impairments. The latter can hinder both their psychosocial adjustment after treatment and their health and well-being over the long term. Little is known about the cause of childhood cancers. Only a small proportion (probably less than 5%) occur in children who have constitutional genetic abnormalities and diseases such as Down syndrome, AIDS, neurofibromatosis and nevoid basal cell carcinoma syndrome. Another small proportion is caused by exposure to chemotherapeutic agents or radiotherapy for a prior malignant disease. 2 Opportunities to prevent cancer in children are therefore limited. This is especially so because screening tests are lacking for most childhood cancers. Diagnosis The International Classification of Childhood Cancers 3 was developed to reflect the differences in childhood cancers compared with cancers in adults in terms of histology, site of origin and tumour behaviour. It classifies childhood cancers under 12 diagnostic groups, with additional subgroups for further refinement. Compared with adults, children have a higher proportion of blood and lymphatic cancers, most commonly leukemia, and cancers of the central nervous system. 1 Cancer is slightly more common in boys than in girls, and the type of cancer diagnosed is likely to vary by age. 1

Esophageal Cancer in Canada: Trends according to Morphology and Anatomical Location

BACKGROUND Esophageal adenocarcinoma has one of the fastest rising incidence rates and one of the lowest survival rates of any cancer type in the Western world. However, in many countries, trends in esophageal cancer differ according to tumour morphology and anatomical location. In Canada, incidence and survival trends for esophageal cancer subtypes are poorly known. METHODS Cancer incidence and mortality rates were obtained from the Canadian Cancer Registry, the National Cancer Incidence Reporting System and the Canadian Vital Statistics Death databases for the period from 1986 to 2006. Observed trends (annual per cent change) and five-year relative survival ratios were estimated separately for esophageal adenocarcinoma and squamous cell carcinoma, and according to location (upper, middle, or lower one-third of the esophagus). Incidence rates were projected up to the year 2026. RESULTS Annual age-standardized incidence rates for esophageal cancer in 2004 to 2006 were 6.1 and 1.7 per 100,000 for males and females, respectively. Esophageal adenocarcinoma incidence rose by 3.9% (males) and 3.6% (females) per year for the period 1986 to 2006, with the steepest increase in the lower one-third of the esophagus (4.8% and 5.0% per year among males and females, respectively). In contrast, squamous cell carcinoma incidence declined by 3.3% (males) and 3.2% (females) per year since the early 1990s. The five-year relative survival ratio for esophageal cancer was 13% between 2004 and 2006, approximately a 3% increase since the period from 1992 to 1994. Projected incidence rates showed increases of 40% to 50% for esophageal adenocarcinoma and decreases of 30% for squamous cell carcinoma by 2026. DISCUSSION Although esophageal cancer is rare in Canada, the incidence of esophageal adenocarcinoma has doubled in the past 20 years, which may reflect the increasing prevalence of obesity and gastroesophageal reflux disease. Declines in squamous cell carcinoma may be the result of the decreases in the prevalence of smoking in Canada. Given the low survival rates and the potential for further increases in incidence, esophageal adenocarcinoma warrants close attention.

Canadian adolescents and young adults with cancer: opportunity to improve coordination and level of care

Cancers in adolescents and young adults (aged 15–29 years) represent a transition between the nonepithelial types, especially acute leukemias and embryonal tumours, that are common during childhood and the epithelial types (i.e., carcinomas) that account for most cancers in older adults. The

Measuring the effect of including multiple cancers in survival analyses using data from the Canadian Cancer Registry

BACKGROUND In survival analyses using cancer registry data, second and subsequent primary cancers diagnosed in individuals are typically excluded. However, this approach may lead to biased comparisons of survival between cancer registries, or over time within a single registry. PURPOSE To examine the impact of including multiple primary cancers in the derivation of survival estimates using data from a population-based national cancer registry. METHODS Five-year relative survival estimates for persons aged 15-99 years at diagnosis were derived using all eligible primary cases from the Canadian Cancer Registry (CCR)-a population-based registry containing information on cases diagnosed from 1992 onward-and then again using first primary cases only. Any pre-1992 cancer history of persons on the CCR was obtained by using auxiliary information. RESULTS The inclusion of multiple cancers resulted in lower estimates of 5-year relative survival for virtually all cancers studied. The effect was somewhat attenuated by age-standardization (e.g., from 1.3% to 1.0% for all cancers combined), and was greatest for bladder cancer (-2.4%) followed by oral cancer (-1.9%)-cancers that had the first and third lowest proportions of first cancers, respectively. For the majority of cancers the difference was less than 1.0%. Cancers for which there was virtually no difference (e.g., lung, pancreatic, ovarian and liver) tended to be those with a poor prognosis. CONCLUSION Inclusion of second and subsequent primary cancers in the analysis tended to lower estimates of relative survival, the extent of which varied by cancer and age and depended in part on the proportion of first primary cancers.

Variation in breast cancer counts using SEER and IARC multiple primary coding rules

Objective: To determine breast cancer case counts, on a given data set, using both Surveillance, Epidemiology, and End Results (SEER) program and International Agency for Research on Cancer (IARC) multiple primary coding rules and to describe differences, if any, by age at diagnosis, histology, stage at diagnosis, laterality, and grade. Methods: SEER and IARC multiple primary coding rules were applied to a dataset provided by the North American Association of Central Cancer Registries. Only registries whose data met high quality data standards for the time period studied (1994–1998) and whose permission was obtained were included. Percentage differences were calculated using IARC counts as the base. Results: Using IARC multiple primary rules resulted in 2.4% fewer cases. Among females, the highest percent changes by category were: age group – 80–84 year-olds (3.4%); histology – inflammatory breast cancer (4.6%); stage – distant (3.1%); grade – well differentiated (3.0%). Among males, the highest percent changes by category were: age group – 80–84 year-olds (1.7%); histology – for intraductal and lobular breast carcinoma in combination (4.8%); stage – distant (3.0%); grade – well differentiated (1.8%). Overall differences were generally unaffected when examined by laterality. Conclusion: Breast cancer case counts are dependent on the multiple primary coding rules used.

Conditional relative survival: a different perspective to measuring cancer outcomes.

Lorraine Shack *, Heather Bryant , Gina Lockwood , Larry F. Ellison d a Population and Public Health, Alberta Health Services, Calgary, Canada Divisions of Oncology and Community Health Sciences, University of Calgary, Calgary, Canada Canadian Partnership Against Cancer, 1 University Ave., Suite 300, Toronto, ON M5J 2P1, Canada Health Statistics Division, Statistics Canada, Ottawa, ON, Canada