One third of deaths in men and one quarter in women are attributed to cancer. Although its associated death rates have been falling over the last two decades, at least for certain types, its overall incidence is on the rise (by 60 % between 1980 and 2000), due to the aging of the population, more extensive application of exploring and screening techniques and environmental causes. The elderly are the most frequently affected, with one third of diagnoses concerning over 75s. But cancer also affects children, although rarely, representing the second cause of death in 1 to 14 year olds (20% of deaths).
Breast cancer is the most common cancer in women (89 in 100,000) and, despite better prognosis, it is also the leading cause of death in women. Around 110,000 women are treated annually in hospitals. In men, prostate cancer is dominant (75 in 100,000), with improved early diagnosis by PSA assay. Every year, 89,000 patients are admitted to hospital. In third place is colorectal cancer (39 in 100,000 men and 25 in 100,000 women), which is the second cause of death in women and the third in men. Lung cancer, which affects 52 men and 9 women in every 100,000, is still the number one “killer” due to its poor prognosis. Incidence has tended to fall in men and rise in women due to the change in smoking trends over the last three decades. Almost all tissues can fall prey to cancer with, in decreasing order of incidence in the French population, the mouth and pharynx, lymph (non-Hodgkin’s malignant lymphoma), bladder, kidney, skin (melanoma), pancreas, stomach, thyroid, liver, uterus, œsophagus, plasmocytes (multiple myeloma), ovary, nervous system, larynx, hematopoietic cells (leukaemia), cervix, testicle and pleura.
Cancers with known causes currently account for 50% of cases. This has enabled prevention policies to be set up against the main known risk factors associated with our environment or behavior: smoking (responsible for 25% of cancer deaths alone), alcohol, sedentary lifestyle, overweight, unhealthy diet, too early or too long sun exposure and occupational exposure to carcinogenic substances. But in half the cases, it is impossible to attribute one or several specific causes to the appearance of cancer. The hypothesis is that these cancers, with complex etiology, are due to an addition or potentialization of low genetic and environmental risks. Genetic research shows ever more convincingly that we are unequal when it comes to cancer: certain genetic polymorphisms associated with metabolism, cell distribution and signaling are associated with a heightened susceptibility in their carriers.
Since early screening helps to guarantee a good prognosis for many cancers, considerable efforts are being made in this respect. Mammographies for women over 50 and screening for colorectal cancer (analysis of blood in stools and coloscopy) in men and women over 50 are now carried out throughout France. Research into predisposition factors, defining preventive strategies for at-risk populations, and diagnostic biomarkers for all cancers for detecting tumor development as early as possible, represents a major challenge in the years to come.
Cancer is a major public health challenge, a human, social, society and economic stake. The high economic cost of this disease for the country is evident, and patients’ associations have highlighted its human and social impact for patients and their loved ones.