We have summarized national screening recommendations for the 21 countries with the highest total healthcare expenditure per capita. These countries were selected because they are likely to have adequate resources for a cancer screening program of some kind; comparison with less well-resourced settings would be unfair and would be less likely to reflect the differences in values, priorities, and the assessment of evidence that we are interested in. As physicians and researchers in the USA, we are especially interested in how our recommendations compare with other countries, and what we can learn from them.
In comparing recommendations, we are not making value judgements or endorsing a single “correct” answer regarding age at initiation, screening interval, or age at cessation of screening. These decisions likely reflect differences between countries and organizations regarding how benefits and harms are valued and balanced at a societal level, the type of evidence considered, the availability of resources and infrastructure for screening (for example, adequate trained medical personnel to perform colonoscopy), whether and how cost is considered, and different standards for assembling, evaluating, and interpreting a complex evidence base. For example, does the body making a recommendation consider only randomized controlled trials with cancer-specific mortality as the outcome, or does it also consider observational data and modeling studies? [20] Does the panel consider outcomes beyond mortality, such as disease progression, cost, stage shifts, or quality of life? Is cost explicitly considered or is the decision made solely on the balance of potential benefits and harms?
Note that in our discussion below, we consider the USPSTF to represent the US national screening recommendation, although recommendations from USA specialty and cancer societies are also presented. Also, when we use the term “more aggressive” or “more conservative” to describe screening recommendations, we refer to recommendations with a broader age range and/or a more frequent interval vs a narrower age range and/or a less frequent interval. Finally, a review of the process used by each country or organization to develop and update guidelines is beyond the scope of this article.
Commonalities
There was considerable homogeneity regarding screening recommendations for breast cancer, cervical cancer, and to some extent, colorectal cancer. A starting age for routine mammography of 50 years was recommended by 16 of 21 countries; all countries but one recommended a biennial interval, and 14 recommended a stopping age of 69 or 70 years. Similarly, most countries recommended cervical cancer screening beginning between 21 and 30 years of age (depending on whether or not testing for human papillomavirus was employed), and most recommended a stopping age between 65 and 70 years. Similarly, most countries recommended that colorectal cancer screening begin at age 50 or 55 years and stop by 75 years. Finally, there is a general consensus against screening for lung cancer and melanoma, with only the USA, Japan, and Canada recommending lung cancer screening and only Germany, Austria, and France recommend some approach to screening for skin cancer.
Differences
The approach to screening for cervical cancer is evolving, with some countries still recommending cytology only, some recommending HPV testing or co-testing, and some giving clinicians the option of choosing the favored approach. Four countries (Iceland, UK, Sweden, and Finland) do not recommend screening for colorectal cancer until age 60, compared to start ages between 40 and 50 years for most other countries. The recommended test for colorectal cancer screening also varies. FIT was most widely recommended, while the USPSTF offered seven different options, and Germany and Austria recommended FIT for younger patients followed by a series of colonoscopies. There is considerable heterogeneity regarding prostate cancer screening: seven countries recommend screening for prostate cancer in some form, while eight explicitly recommend against it. This is likely due to variation in how guideline panels assess the potential benefits and harms.
Variation by country and type of organization
For prostate cancer screening, of the seven countries with a recommendation to screen or screen selectively for prostate cancer, five were from the top half of the selected countries based on per capita health expenditures. Four of the five countries with the shortest interval for colorectal cancer screening (Iceland, UK, Finland, and New Zealand) are among the six lowest spending countries. However, there was no apparent association between per capita health expenditures and the intensity of screening for breast and cervical cancer.
Other than within the USA, there was no clear difference in terms of the intensity of screening recommendations coming from national guideline committees, cancer societies or leagues, and specialty societies. In the USA, the recommendations regarding mammography from the American Cancer Society, American College of Obstetrics and Gynecology, and American College of Radiology were the only ones identified that recommended annual screening and also had longer screening intervals for patients at average risk. The American College of Radiology was the only body that recommended annual mammography starting at age 40 years, with no specified stopping age. On the other hand, there is considerable similarity regarding colorectal cancer screening between the USPSTF, ACS, and specialty society guidelines.
Prostate cancer screening recommendations are now similar between the USPSTF draft recommendation of 2017 and the American Urology Association, and recommendations regarding cervical cancer screening between the USPSTF, ACS, and ACOG are nearly identical. Assuming that they are based on the best available evidence, this kind of “harmonization” between guidelines from different groups within a country sends a clear, unified message to patients and physicians. In the absence of such harmonization, confusion may reign and physicians may do what feels right or what is requested by patients rather than what is supported by the best evidence. Due to medicolegal concerns, some physicians may feel compelled to practice based on the most aggressive set of recommendations or based on patient request. This is especially true in the USA context, where “failure to diagnose” is the most common reason for a malpractice lawsuit [21].