* Cases diagnosed from 1992 to 1995 Childhood and adolescent cancer survival: A period analysis of data from the Canadian Cancer Registry Larry F. Ellison, Statistics Canada

Co-authors Lisa Pogany, MSc, and Leslie S Mery, MSc  Centre for Chronic Disease Prevention and Control, Public Health Agency of Canada

Overview Introduction Purpose Data source - Canadian Cancer Registry Methods Results Perspective Main conclusions Momentum

Introduction Cancer is the 4 th leading cause of death in Canada among those under 20 years of age. Estimates of survival among children and adolescents were outdated in Canada.  Only previous study based on data from the late 80s. Recent reports from Europe and the United States had indicated that the considerable improvement in survival seen over the last several decades was ongoing.

Introduction Survival estimates were derived using period analysis instead of a traditional cohort analysis.  Period survival analysis exclusively reflects the survival experience in the most recent period for which data are available.  Period estimates generally provide better predictions of survival for those recently diagnosed with cancer.

Purpose To provide Canadian predictions of the short- and long-term survival of children and adolescents recently diagnosed with cancer. To compare long-term period method cancer survival estimates to traditional cohort-based estimates.

Canadian Cancer Registry Cases identified using the Canadian Cancer Registry (CCR). CCR is a dynamic, person-oriented, population-based database containing cases diagnosed from 1992 onward. Comprised of data supplied by the provincial and territorial cancer registries whose cooperation is gratefully acknowledged. Maintained by Statistics Canada.

Methods Cases classified using ICCC-3. Restricted to first primary cancer cases. Includes cases aged 0 to 19 at diagnosis. Excludes autopsy only and death certificate only cases. Excludes cases diagnosed in province of Quebec.

Methods Vital status determined by record linkage to the Canadian National Mortality Database.  supplemented by data from provincial / territorial registries Observed survival proportions (OSP) were derived using the period analysis method ( ).

, , 44, , 33, 44, , 22, 33, 44, , 22, 33, 44, , 22, 33, , 22, , NOTE: The numbers within the cells represent year(s) of follow-up since diagnosis. Data used to calculate five-year period survival estimates Follow-up Year Diagnosis Year

Survival* for all diagnostic groups combined *Canada (excluding Quebec), ages 0-19 years, Canadian Cancer Registry,

* Canada (excluding Quebec), ages 0 to 19, Canadian Cancer Registry, Five-year observed survival* by diagnostic group Diagnosis Group I Leukaemias, myeloproliferative & myelodysplastic diseases81 (79-83) II Lymphomas and reticuloendothelial neoplasms88 (86-90) III CNS and miscellaneous intracranial & intraspinal neoplasms75 (73-78) IV Neuroblastoma and other peripheral nervous cell tumours70 (64-76) V Retinoblastoma99 (92-100) VI Renal Tumours91 (86-94) VII Hepatic Tumours68 (55-78) VIII Malignant bone tumours68 (62-73) IX Soft-tissue and other extraosseous sarcomas77 (71-81) X Germ cell tumours, etc.88 (84-91) XI Other malignant epithelial neoplasms & malign. melanomas91 (88-93) XII Other87 (77-93) OSP (95%CI)

Survival* for common leukaemia sub-types *Canada (excluding Quebec), ages 0-19 years, Canadian Cancer Registry, ** AML = acute myeloid leukaemias

Observed survival* by age group for selected diagnostic groups Age group, 5-year OSP (95% CI) Diagnostic group < Leukaemia 57 (45-67)90 (87-92)85 (80-88)82 (76-87)59 (52-66) CNS** 55 (38-68)72 (66-77)74 (68-79)81 (76-86)77 (71-83) Neuroblastoma 94 (85-97)60 (51-68)55 (36-70)-- *Canada (excluding Quebec), 0 to 19 years, Canadian Cancer Registry, ** CNS = central nervous system and miscellaneous intracranial & intraspinal neoplasms

Comparison of most recent period and cohort five-year survival estimates* Diagnostic (sub) Group Period Method OSP (%) Cohort Method OSP (%) Difference (%) All Combined AML** NHL** Nephroblastoma Malignant bone tumours *Canada (excluding Quebec), 0 to 19 years, Canadian Cancer Registry, ** AML = acute myeloid leukaemia; NHL = non-Hodgkin’s lymphoma

Comparison to previous Canadian study The overall five-year survival of 82% for children and adolescents ages 0 to 19 years was 11% higher than previously reported for Canada (based on data from the late 1980s). Among diagnostic groups, the largest absolute survival increases were observed for hepatic tumours (20%), leukaemias (15%), and CNS neoplasms (14%). Absolute increases were greatest for those diagnostic groups originally found to have the lowest survival.

Comparison to previous Canadian study An alternative index of the change in survival which depends less on the original survival estimate is the percent change in cumulative probability of death—a measure of the proportion of deaths avoided. The overall increase in five-year survival from 71% to 82% corresponds to a 37% decrease in the cumulative probability of death at five years. Among diagnostic groups, the decrease was greatest for retinoblastoma (70%) and least for renal tumours (0%).

Main conclusions There has been substantial improvement in childhood and adolescent cancer survival in Canada since the late 1980s. Period estimates of five-year survival were similar to (< 1.0% difference) or greater than the corresponding cohort estimates for all diagnostic groups and subgroups analysed.

Dissemination Published in the European Journal of Cancer.  Ellison LF, Pogany L, Mery LS. Eur J Cancer 2007; 43: Notice of release in Statistics Canada’s The Daily  ( 4/d070724e.htm) Presented at the 29 th IACR annual meeting.

Momentum of study Impetus for the special topic on childhood cancer in Canadian Cancer Statistics 2008 ( Short report to be published in the Canadian Medical Association Journal later this year focusing on childhood cancer survival and issues faced by survivors.

Contact information Larry Ellison, Health Statistics Division, Statistics Canada Phone: