Trends in cancer incidence and mortality in Vaud, Switzerland, 1974-1993

Comparing incidence of and mortality from cancer within a given population yields several benefits. One of these is the opportunity, when trends in incidence differ from those in mortality, to derive inferences about the potential role of improved diagnosis in the rise of incidence rates, and about therapeutic advancements in reducing mortality.

Trends in incidence of and mortality from various cancers or groups of cancers (comprising 55,682 new malignant tumours and 26,528 certified cancer deaths) over the period 1974-1993 were compared using, respectively, data from the Cancer Registry of the Swiss Canton of Vaud (with about 600,000 inhabitants) and those provided by the Swiss Federal Statistical Office.

The overall cancer incidence increased by 10% to 30% in both sexes and various age groups, whereas mortality remained approximately the same. The sites primarily responsible for these divergent trends were breast, prostate and colorectal, three sites where cancers have been less frequently diagnosed since the advent of certain technical advancements and the introduction of screening. Other contributors to the divergent trends were testicular cancer, Hodgkin's disease and leukaemias, i.e., the sites for which the most substantial therapeutic advancements have been achieved.

These data are fairly reassuring, since they are inconsistent with an ongoing cancer epidemic in this European population. However, they are also incompatible with the presence of major advancements in the prevention and treatment of cancer.