New UK and US research alliance aims to detect cancer earlier and improve screeningBMJ 2019; 367 doi: https://doi.org/10.1136/bmj.l6104 (Published 21 October 2019) Cite this as: BMJ 2019;367:l6104
All rapid responses
The two reports about improving cancer screening (one about a new international alliance to develop new strategies and technologies to detect cancer earlier(1) and one about the government commissioned review recommending NHS to provide more convenient access to screening services to increase early diagnosis and improve survival rates(2) were optimistic, at best.
The NEJM just provided an illuminating report about the epidemiologic-signatures approach.(3) It included simple tables for most frequent cancers during the 1975-2015 period with mortality, incidence, mortality metastatic incidence (cases in which cancer is first diagnosed when a patient presents with metastases, not those in which early-stage cancer is diagnosed and then progresses to metastatic disease). This allows us to make a distinction between data for overdiagnosis (harm from diagnosis of cancers that would otherwise not become clinically evident, the drawback of screening) and true cancer occurrence (clinically meaningful cancer, reported incidence minus overdiagnosis).
Obviously, the increase in incidence of cancer with the introduction of widespread screening combined with stable incidence of metastatic disease is evidence for overdiagnosis.
A decline in mortality is more ambiguous as it can reflect either improved treatment or screening or some combination of the two. However, progresses in treatment effectiveness are strongly evidence based. In contrast, the effectiveness of screening in real life seems unlikely when considering the poor uptake and the time frame. For example, in the US, colorectal cancer mortality is 1.45/10,000 per year, and was already falling steadily from 2.45 in 1990, long before screening was implemented.(https://seer.cancer.gov/statfacts/html/colorect.html) Moreover, first randomized controlled trials for colorectal cancer screening showed that mortality was reduced at best after 8 to 13 years of screening in two trials and not until after 15 to18 years of screening in another two trials, in highly selected individuals who were compliant to biannual fecal testing and uptake of endoscopy following positive test. Presently, national screening programs only dare to publish the uptake for one round of screening. A smoke screen!(4)
Last, the cart should not be put before the horse. The priority for improving cancer screening is first to improve informed consent and share decision making. The NHS must provide leaflets with common-sense pictographs that use absolute numbers (with a consistent denominator, such as /1000 screened), time frames and visuals employing the same scale for information on gains and losses of the options, as these have been shown to change and improve decision-making. The icon array diagrams produced by the Harding Center for Risk Literacy (https://www.harding-center.mpg.de/en/fact-boxes/early-detection-of-cancer) are an excellent example. Healthcare professionals must implement the 4-Step Method: a) Trigger, indicating that all options are acceptable; b) Administer the information (as above); c) Promote active participation of the patient by the expression of his or her values; and d) Analyze if the patient is comfortable with the decision by rephrasing.(5)
1 Mahase E. New UK and US research alliance aims to detect cancer earlier and improve screening. BMJ 2019;367:l6104.
2 Iacobucci G. Cancer screening: more convenient access will boost early diagnosis, says review. BMJ 2019;367:l6059.
3 Welch HG, Kramer BS, Black WC. Epidemiologic Signatures in Cancer. N Engl J Med 2019;381:1378-1386.
4 Braillon A. Can surrogate end points from a first-round screening be reliable for colorectal cancer screening? Gastroenterology 2012;142:e29.
5 Braillon A, Bewley S. Shared Decision-Making for Cancer Screening: Visual Tools and a 4-Step Method. JAMA Intern Med 2015;175:1862.
Competing interests: MP is the editor of HealthWatch Newsletter for Science and Integrity in Medicine.(https://www.healthwatch-uk.org/publications/newsletter.html)