AMSTERDAM — The evidence for colorectal cancer (CRC) screening is much stronger and clearer than that for either breast or prostate cancer screening, and so funding for nationwide screening programs should be targeted at CRC, researchers said here at the European Cancer Congress 2013.
Screening for CRC reduces mortality from the disease. "The evidence could not be clearer," said Philippe Autier, MD, MPH, vice president of population studies at the International Prevention Research Institute in Lyon, France.
He was presenting data from a large a European survey, spanning 1998 to 2010, showing that the largest falls in CRC mortality were seen in the countries where the greatest proportions of the population were screened (whether by fecal blood tests or sigmoidoscopy or colonoscopy). The method of screening is not that important, he said; the important thing is to "do something."
There is a clear relation between randomized clinical trials, data from cancer registries, and declines in CRC mortality over time, he said.
In contrast, there is no such smooth logical sequence between randomized trails and population studies for breast cancer screening. For prostate cancer, the situation is even more controversial, he commented, and referred to another presentation at the meeting that concluded that screening with prostate-specific antigen results in more harm than benefit.
"It seems to us that there is now an irrefutable case for devoting some of the resources from breast and prostate cancer screening to the early detection of CRC," Dr. Autier concluded.
"Pressure should be put on national health services to put more effort into organizing [CRC] screening programs," president of the European CanCer Organisation (ECCO), Cornelis van der Velde, MD, from the Leiden University Medical Center in the Netherlands, commented in a statement.
"Evidence Is Overwhelming"
Dr. Autier said the evidence for cervical cancer screening is also very clear.
"If you look at the cost of screening versus what you get in terms of reduction of mortality, at present it seems quite clear that for every euro or dollar you spend on screening, the return is better for cervical cancer screening and even better for colorectal cancer screening than it is for breast cancer screening and prostate cancer screening, where we are really spending money for doing a lot of harm," he said at a press conference.
A big difference is that there is a very high risk of a false positive with breast and prostate cancer screening, Dr. Autier said. There is also the potential for overdiagnosis and overtreatment, and this screening leads to an increase in the incidence of these cancers.
In contrast, screening for colorectal and cervical cancer screening is actually looking for a precursor lesion — cervical intraepithelial neoplasia in the case of cervical cancer and polyps in the case of CRC, he explained. "When you remove these precursor lesions, you prevent the cancer — this is the best scenario for screening," he said, and it decreases the incidence of the disease. "Most of these precursor lesions will not turn into cancer, but the systematic removal of these lesions will avoid cancer, as it removes the ones that would turn into cancer," he added.
Discussant for the study, Jack Cuzick, PhD, professor of epidemiology at the Wolfson Institute of Preventive Medicine at Queen Mary University of London, United Kingdom, said this was "an important talk."
Screening for CRC is "the most effective screening modality that we have for making an impact on a major cancer," he said.
"We have to find a way to use it more," he added, emphasizing the need to promulgate these findings in an active away to the general public.
Dr. Cuzick also mentioned the use of aspirin as an effective strategy for preventing CRC, but added there needs to be a consensus reached on who are the individuals that would benefit most.
Results From the Survey
Dr. Autier presented results on CRC screening collected in the Survey of Health Ageing and Retirement in Europe (SHAPE), conducted in 11 European countries between 1989 and 2010. The researchers used data from the World Health Organization database on causes of death to calculate changes in CRC mortality in the different countries, and related this back to the uptake of screening in adults over 50 years of age.
Overall, for the 11 European countries in the survey, CRC mortality fell by 73% in men and 82% in women.
Most of the countries showed a reduction in CRC mortality over the study period, but not all; a glaring exception was Greece.
"We saw quite clearly that the greater proportion of men and women who were screened, the greater the reductions in mortality," Dr. Autier said.
In Greece, only 8% of males reported having an endoscopy, and CRC mortality increased by 30% in males in the study period, and fell by only 2% for women.
In contrast, in Austria, 61% of survey participants had had a fecal blood test, and 35% of males had undergone an endoscopic examination. CRC mortality dropped by 39% in men and 47% in women during the study period.
Dr. Autier said that there were many differences across Europe in what was available. There is a national program for fecal blood testing in France and the United Kingdom, and for both fecal blood testing and endoscopy in Germany and some Italian regions, but in other countries, screening is left up to individuals and their doctors. Many countries do not have a national program, he pointed out.
The survey shows that there are major differences in screening across European countries, commented Dr. van der Velde, and it is disappointing to see the low levels of screening in some countries. It is an ECCO priority to harmonies CRC screening throughout Europe, so that every individual "gets the best chance of early detection," he added.
European Cancer Congress 2013 (ECCO-ESMO-ESTRO): Abstract 1405. Presented September 29, 2013.
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Cite this: Spend More on CRC Screening, Less on Breast and Prostate - Medscape - Sep 30, 2013.