Collaborative study: Francim Network, Biostatistics Department of the Hospices Civils de Lyon, French Institute for Public Health Surveillance, National Cancer Institute. The main objective of this study is to provide, for 47 cancer sites across all stages, estimates of crude and net survival at 1, 3, 5, and 10 years after a cancer diagnosis, based on population data provided by the Francim network registries. The study covers all new cases of cancer diagnosed in individuals aged 15 and older during the 1989–2004 period, totaling 427,000 cases. The results are presented by sex, age group, and diagnosis period. Net survival among cancer patients varies considerably depending on the cancer site. Cancers with a poor prognosis (10-year net survival rate below 33%) account for 40% of cancers in men and 16% in women. Cancers with a good prognosis (10-year net survival rate of 66% or higher) account for 52% of cancers in women and 28% in men. For the same type of cancer, women most often have a higher survival rate than men. A younger age at diagnosis is very often a favorable prognostic factor. An improvement in 5-year net survival was observed between 1989 and 2004 for most of the cancers studied. This improvement may have different causes depending on the cancer. It may result from earlier diagnosis due to screening or from improved therapeutic management, or a combination of both. Other mechanisms may exist depending on the cancer site. These various factors are discussed for the 47 cancer sites presented in this book. (R.A.)