Survival comparisons between populations or population groups (using funnel plots)

Transcription

1 Survival comparisons between populations or population groups (using funnel plots) Manuela Quaresma Cancer Research UK Cancer Survival Group London School of Hygiene and Tropical Medicine EPAAC WP9 Satellite Meeting Ispra, January 2014

2 Important points to consider for a fair comparison a priori of survival estimation: Data collection: a common protocol Centralised quality control of data Strict control of background mortality Standardised analytic techniques, including software Age-standardisation of estimates a posteriori of survival estimation: Use funnel plots for survival comparisons Survival comparisons between populations or population groups Ispra, January /12

3 Funnel plots for survival / excess hazard comparisons between populations Survival comparisons between populations or population groups Ispra, January /12

4 Funnel plots for survival / excess hazard comparisons between populations Survival comparisons between populations or population groups Ispra, January /12

5 Example 1: USA component of cancer survival in five continents (CONCORD) Coleman et al, Lancet Oncology 2008 Adults diagnosed and followed up to 31 December 1999 Relative survival up to five years Background mortality: sex, single year age, calendar year, geographic area, race (black, white) Age-standardised: International Cancer Survival Standard (ICSS) Survival comparisons between populations or population groups Ispra, January /12

6 Example 1: Area-specific survival by race and cancer registration system Survival comparisons between populations or population groups Ispra, January /12

7 Example 2: Index of cancer survival by Clinical Commissioning Groups (CCG) Quaresma et al, Office for National Statistics, 2013 CCGs: responsible for health-commissioning in England All adults diagnosed , follow-up December 2012 Net survival using flexible parametric regression models Age-cancer-sex standardised Survival comparisons between populations or population groups Ispra, January /12

8 Example 2: Index of one-year net survival by CCGs Survival comparisons between populations or population groups Ispra, January /12

9 Example 3: Regional differences in cancer survival, Japan Ito Y et al, Cancer Science 2009 Wide differences in 5-year relative survival between 6 prefectures in Japan Aim: To determine how much age and stage at diagnosis could explain the differences in survival Regression models for relative survival (Poisson): successive adjustments: (follow-up time, region) + (age) + (stage) inclusion contrast: compare excess hazards for each region with excess hazard averaged for all regions combined Survival comparisons between populations or population groups Ispra, January /12

10 Example 3: Excess hazard of death by prefecture: stomach cancer, men Survival comparisons between populations or population groups Ispra, January /12

11 Potential difficulties: Over-dispersion and precision Overdispersion More variability than expected Insufficient risk adjustment? Over-dispersion factor: Winsorising Random-effects model Precision Interpretation - not as intuitive as sample size (N)? Loss in precision with successive adjustments? Wide range in precision: large vs small regions Survival comparisons between populations or population groups Ispra, January /12

12 References Spiegelhalter, DJ. Funnel plots for comparing institutional performance. Stat.Med., 2005 Spiegelhalter, DJ. Handling over-dispersion of performance indicators. Quality Safety Health Care, 2005 Quaresma, M. et al. Funnel plots for population-based cancer survival: principles, methods and applications. Stat.Med., 2013 Command Funnel plot for cancer survival - R and STATA software (to be available in 2014) Survival comparisons between populations or population groups Ispra, January /12