Patterns and trends in cancer survival
The Special Issue accompanying Cancer in Norway 2007 shows that patients diagnosed with cancers of the thyroid or testis, whom have survived one year have a conditional survival close to 100 per cent. In other words, their risk of dying is not so different from the general population.
The report, entitled Long-term cancer survival: patterns and trends in Norway 1965–2007, aims to provide visual descriptions of the patterns of long-term cancer survival in Norway today, as well as illustrate the major trends over the last 40 years.
- The statistics generated provides a detailed examination of the survival experience of Norwegian cancer patients. In collaboration with our colleagues in the health and research community, we hope it will also yield vital research into cancer care in Norway and further our mutual efforts in improving the control of cancer, says editor-in-chief Freddie Bray.
Substantial variability in patient survival
The report focuses on patients diagnosed with 23 common forms of cancer which are responsible for 85 per cent of all cancer types diagnosed in 2007. Cancer survival was analysed over four decades from 1965 up to and including 2007. The report uses a number of statistical approaches to describe the national survival of cancer patients in Norway. The methods allow the most recent data to be included in the survival calculations, including information on the survival of patients diagnosed in 2007.
- Therefore we are able to provide up-to-date survival estimates that in part reflect the prognosis of cancer patients in Norway today. There is substantial variability in patient survival dependant on the type of cancer diagnosed, says Bray.
Cancers associated with very good prognosis (with a 5-year survival greater than 70 per cent) include Hodgkin lymphoma and melanoma of the skin, while cancers of such as lung and pancreas generally have poor prognosis (5-year survival 10 per cent or less). The prognosis is however reasonably good for many cancer types, with 5-year survival above 50 per cent for 16 of the 23 cancer types studied.
- We also include analyses that attempt to better quantify the lives of cancer patients beyond their initial diagnosis, estimating conditional survival, which quantifies the prognosis of patients who have survived a given number of years after diagnosis, says Bray.
This has a positive message: for patients able to survive some time after diagnosis, their chances of survival rapidly improve with each additional year survived. To illustrate, patients diagnosed with cancers of the thyroid or testis, whom have survived one year have a conditional survival close to 100 per cent, or in other words, their risk of dying is not so different from the general population.
Women who have survived five years after breast, cervix or corpus cancer, have good prospects of surviving their illness, as their 5-year relative survival conditional on surviving five years is 90 per cent or more.
Expertise from the clinical and research milieu will be critical in interpreting these complex patterns. The Cancer Registry of Norway will actively seek collaboration among the community to initiate research to better understand the diagnostic, treatment and management-related factors involved in these cancer survival patterns, with a view to further improving public health, as well as cancer services in Norway.