Conditional net survival: Relevant prognostic information for colorectal cancer survivors. A French population-based study.
BACKGROUND
Traditionally, survival estimates have been reported as survival from the time of diagnosis. A patient's probability of survival changes according to time elapsed since the diagnosis and this is known as conditional survival. The aim was to estimate 5-year net conditional survival in patients with colorectal cancer in a well-defined French population at yearly intervals up to 5 years.


METHODS
Our study included 18,300 colorectal cancers diagnosed between 1976 and 2008 and registered in the population-based digestive cancer registry of Burgundy (France). We calculated conditional 5-year net survival, using the Pohar Perme estimator, for every additional year survived after diagnosis from 1 to 5 years.


RESULTS
The initial 5-year net survival estimates varied between 89% for stage I and 9% for advanced stage cancer. The corresponding 5-year net survival for patients alive after 5 years was 95% and 75%. Stage II and III patients who survived 5 years had a similar probability of surviving 5 more years, respectively 87% and 84%. For survivors after the first year following diagnosis, five-year conditional net survival was similar regardless of age class and period of diagnosis.


CONCLUSIONS
For colorectal cancer survivors, conditional net survival provides relevant and complementary prognostic information for patients and clinicians.
Digestive Cancer Registry of Burgundy, INSERM U866, University Hospital Dijon, University of Burgundy, Dijon, France. Electronic address: antoinedrouillard@hotmail.com.
Antoine
A
Drouillard
Digestive Cancer Registry of Burgundy, INSERM U866, University Hospital Dijon, University of Burgundy, Dijon, France.
Anne-Marie
AM
Bouvier
Digestive Cancer Registry of Burgundy, INSERM U866, University Hospital Dijon, University of Burgundy, Dijon, France.
Fabien
F
Rollot
Digestive Cancer Registry of Burgundy, INSERM U866, University Hospital Dijon, University of Burgundy, Dijon, France.
Jean
J
Faivre
Digestive Cancer Registry of Burgundy, INSERM U866, University Hospital Dijon, University of Burgundy, Dijon, France.
Valérie
V
Jooste
Digestive Cancer Registry of Burgundy, INSERM U866, University Hospital Dijon, University of Burgundy, Dijon, France.
Côme
C
Lepage
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D016019:Survival Analysis
Colorectal cancer; Conditional survival; Net survival; Population-based study