SWEDEN HAS THE BEST CANCER SURVIVAL BETWEEN NORDIC COUNTRIES

August 12, 2010 — Although there are many similarities among Nordic countries and their cultures, there are some differences in cancer survival rates. Iceland, Norway, Sweden, and Finland have the highest cancer survival rates in Europe, but Denmark lags behind.

A study published in the June issue of Acta Oncologica found that Danish cancer patients had the lowest 5-year survival rates for 23 of the 33 cancer sites evaluated for men and for 26 of 35 sites in women.

For men, Finland had the lowest survival for 6 sites and Norway had the lowest survival for 7 sites. Conversely, Sweden did not rank lowest for any type of cancer, and had the highest survival for 16 cancer sites, followed by Finland (15 sites), Norway (7 sites), and Denmark (1 site).

The differences in 5-year relative survival between the countries were 10 percentage points or more for 12 of the cancers sites, including the prostate, small intestine, penis and other genital organs, kidney, tongue, eye, thyroid, stomach, bone, and colon.

Among women, the pattern was similar to that seen in men. For 16 sites, including the tongue, kidney, stomach, small intestine, colon, thyroid, bone, bladder, and ovary, the differences were 10 percentage points or more.

The authors, led by Hans H. Storm, MD, from the Danish Cancer Society, conclude that the notable differences in cancer survival among Nordic countries "can be linked to national variations in risk factors, comorbidity, and the implementation of screening."

"As stated in our paper, we suspect tobacco consumption and alcohol consumption — leading to comorbidities — and the lack of nationwide screening programs to be the reasons behind the poor survival," Dr. Storm told Medscape Medical News. "We observed the same pattern for all sites — even those where early diagnostic procedures are not at play; hence, tobacco and alcohol seem to be the best candidates."

He added that the public attitude toward seeking medical care early and a reluctance to take symptoms seriously by both doctors and patients might also play a role. "However, an earlier analysis [Eur J Cancer. 2006;42:2773-2780] we did on breast cancer showed that the survival differences between Denmark and Sweden vanished when we limited the analysis to cases detected by mammography," he said.

National Efforts in Place

Survival differences among cancer patients residing in Nordic countries have been previously reported. The most recent analysis of Nordic countries (APMIS. 1995;103[Suppl 49]:1-161), conducted in 1995, showed that Danish patients had the lowest survival, the authors explain. These findings were confirmed when some of the data were reanalyzed by the EUROCARE (European Cancer Registry-Based Study of Cancer Patients' Survival and Care) group, which found that except for Denmark, the Nordic countries have the highest cancer survival in Europe.

The most recent version of the study, EUROCARE-4, found that Denmark and the United Kingdom have lower survival rates than countries with similar spending on healthcare. In contrast, Iceland, Norway, Sweden, and Finland continue to have "excellent overall cancer survival."

There have been national efforts in Nordic countries to control cancer mortality, note the authors. Finland formulated a plan for preventing cancer in 1984, which highlighted the need for education, improved nutrition, research, alcohol and tobacco control, and protection against environmental risks. A comprehensive cancer plan was launched in Norway in 1997, and Sweden has had national and regional programs based on clinical guidelines since the 1970s. In Denmark, a comprehensive cancer-control plan was initiated in 2000, with a follow-up plan in 2004.

"The Danish government has issued 3 cancer-control plans since 2000, but the effects have yet to be observed," Dr. Storm said. "Treatment is now up to standard; however, prevention, especially the regulation of tobacco, is lagging far behind that of the other Nordic countries."

Variations in Survival Observed

In the current study, the authors used the NORDCAN database to analyze incidence, mortality, and survival trends in Denmark, Finland, Iceland, Norway, and Sweden. They assessed 5-year relative survival and excess mortality rates in the first 3 months after a cancer diagnosis, and then 2 to 5 years after diagnosis.

They found that survival trends from 1989 to 2003 were generally similar in the different countries, with increases observed in 14 sites among men and 16 sites in women. In all countries, excess mortality rates were highest during the first 3 months after diagnosis. The rates observed during those first 3 months, note the authors, appear to reflect the overall pattern of relative survival: in general, Denmark has higher excess mortality rates than the other Nordic countries, and the male–female survival differences are most evident in the excess mortality seen early in the follow-up.

For the period 2 to 5 years after diagnosis, the absolute differences largely disappeared; relative differences, however, remained or increased slightly for some of the more common malignancies, including colon, rectum, lung, and breast (females) cancers, and melanoma. Other types of cancer, including that of the esophagus, liver, gallbladder and biliary tract, pancreas, lung, and pleura, and multiple myeloma, were found to have high absolute excess mortality rates after 2 years.

Too Early for Results

The study was initiated to not only provide a comprehensive overview of survival among patients living in Nordic countries, but also to examine the effects of cancer-control programs, they write. Even though there are cancer-control programs in both Denmark and Norway, the authors point out that they are unable to observe, as yet, a direct impact on incidence, mortality, or survival.

"It may be too early to see the results compared to Sweden and Finland," they write. "The cancer care plans in Sweden that improved the quality of cancer care, and the Finnish prevention plan that led to an improved general health, were instigated several decades ago."

They add that for "observable changes in cancer incidence and mortality, prevention activities usually surface many years or several decades after initiation, whilst new effective therapies will show up rather rapidly, if applied to the majority of patients."

The Nordic Cancer Union has financially supported the development of the NORDCAN database and program, as well as the survival analyses in this project. The authors have disclosed no relevant financial relationships.

Acta Oncol. 2010;49:532-544. Abstract