Net survival, the survival that might occur if cancer was the only cause of death, is a major epidemiological indicator.
Recent findings have shown that the classical methods used for the estimation of net survival from cancer registry data, referred as to “relative-survival methods,” provided biased estimates.
Dr Rollot and colleagues provided long-term net survival rates for colorectal cancer by using a population-based digestive cancer registry.
The research team performed a population-based cancer registry analysis.
The recently proposed unbiased nonparametric Pohar-Perme estimator was used.
|10-year net survival increased from 21% to 49%|
|Diseases of the Colon & Rectum|
Overall, 14,715 colorectal cancers diagnosed between 1976 and 2005 and registered in the population-based digestive cancer registry of Burgundy (France) were included.
The team's primary outcome measured was cancer net survival, that might occur if all risks of dying of other causes than cancer were removed.
The research team found that the 10-year net survival increased from 31% during the 1976 to 1985 period to 47% during the 1986 to 1995 period and then leveled out.
The team noted a major improvement in 10-year net survival after resection for cure and for stage I to III.
It was striking for stage III cancers, for which 10-year net survival increased from 21% to 49%.
The researchers observed that corresponding net survivals were 70% and 87% for stage I, and 49% and 65% for stage II.
These trends can be related to the decrease in operative mortality, the increase in the proportion of patients resected for cure, and the improvement in stage at diagnosis.
The team observed that trends mainly seen between 1976 and 1995, explaining why survival leveled out after 1995.
Dr Rollot's team concluded, "Further improvements for colorectal cancer management can be expected from more effective treatments and from the implementation of organized cancer screening."