Abstract
OBJECTIVES: To investigate patterns of survival among brain cancer patients in Canada. METHODS: Canadian Cancer Registry data were obtained for all patients with first-ever primary malignant brain tumours diagnosed between 1992 and 2008 (n = 38,095). Follow-up ended with patient death or December 31, 2008, whichever occurred first. Crude Kaplan–Meier estimates were calculated at one, two and five years post-diagnosis. Cox proportional hazard models were used to obtain adjusted hazard ratios by region for major histology types. A time-specific generalized linear model was used to obtain 5-year survival estimates for specific age group, sex and region for major histology types.
RESULTS: The overall five-year survival rate was 27%. No significant difference in survival rate over time is observed. The highest 5-year survival rate was 65% (95% CI: 62.5%–67.4%) for oligodendrogliomas and the lowest was 4.0% (95% CI: 3.7%–4.3%) for glioblastomas. Compared to Ontario, the adjusted 5-year glioblastoma survival estimates were lower in British Columbia, Alberta and the Prairie provinces (Manitoba and Saskatchewan), while the survival estimates were lower in all other regions for diffuse astrocytoma, and lower in Manitoba and Saskatchewan for anaplastic astrocytomas. Estimates were significantly higher for oligodendrogliomas in Alberta, and for anaplastic oligodendrogliomas in Alberta and Quebec (p < 0.05).
CONCLUSION: These data are consistent with previous literature in observing higher survival rates at younger ages, in female patients and for tumours with mixed oligo components. There is a need to further explore the underlying reasons for the observed variation in survival rates by region in an effort to improve the prognosis of brain cancer in the Canadian patient population.
Key Words: Brain neoplasms, survival rate, Canada
Résumé
OBJECTIFS: Étudier les profils de survie des patients atteints d’un cancer du cerveau au Canada.
MÉTHODE: Nous avons obtenu les données du Registre canadien du cancer sur tous les patients atteints d’une première tumeur cérébrale maligne primaire diagnostiquée entre 1992 et 2008 (n = 38 095). Le suivi s’est terminé au décès des patients ou au 31 décembre 2008, selon la première des deux éventualités. Des estimations de Kaplan-Meier brutes ont été calculées à un, deux et cinq ans après le diagnostic. Nous avons utilisé des modèles des risques proportionnels de Cox pour obtenir des coefficients de danger ajustés par région pour les grands types histologiques, respectivement. Un modèle linéaire généralisé dans le temps a servi à obtenir des estimations de survie après 5 ans par groupe d’âge, par sexe et par région pour les grands types histologiques. k ]RÉSULTATS: Le taux de survie global était de 27 %. On n’observe aucun écart significatif dans le taux de survie au fil du temps. Le taux de survie le plus élevé après 5 ans était de 65 % (IC de 95 %: 62,5 %–67,4 %) pour les oligodendrogliomes; le plus faible était de 4 % (IC de 95 %: 3,7 %–4,3 %) pour les glioblastomes. Comparativement à l’Ontario, les estimations ajustées de survie au glioblastome après 5 ans étaient inférieures en Colombie-Britannique, en Alberta et dans les provinces des Prairies (Manitoba et Saskatchewan), tandis que les estimations de survie étaient inférieures dans toutes les autres régions pour les astrocytomes diffus, et inférieures au Manitoba et en Saskatchewan pour les astrocytomes anaplasiques. Les estimations étaient sensiblement plus élevées pour les oligodendrogliomes en Alberta, et pour les oligodendrogliomes anaplasiques en Alberta et au Québec (p < 0,05).
CONCLUSION: Ces données sont conformes à celles d’études antérieures où l’on a observé des taux de survie supérieurs chez les jeunes patients, chez les femmes et pour les tumeurs mixtes (oligo-astrocytomes). Il faudrait pousser la recherche sur les raisons sous-jacentes de la variation observée des taux de survie par région afin d’améliorer le pronostic du cancer du cerveau dans la population de patients au Canada.
Mots Clés: tumeurs du cerveau, taux de survie, Canada
Footnotes
Acknowledgements: This research was conducted with funding from Brain Tumor Foundation of Canada.
Conflict of Interest: None to declare.
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