Invited Perspective: Good Measure—Assessing the Impact of Cancer Hazard Identification on Policies for Cancer Prevention

The translation of research on causes of cancer into preventive action is a multistep process. Advocates for the risk assessment paradigm argue that all steps in a risk characterization should be undertaken at the outset so as to maximize the utility of the information.¹ By contrast, proponents of cancer hazard identification have long contended that the ascertainment of the carcinogenicity of an agent, whether chemical (e.g., benzene), physical (e.g., solar radiation), biological (e.g., human papillomavirus), or a complex mixture (e.g., tobacco smoking), is a necessary first step in cancer prevention, regardless of whether such hazard identification is accompanied by all steps of risk characterization.^2,3 However, formal documentation of the impact of authoritative hazard identification programs has been lacking.

In this issue of Environmental Health Perspectives, Mehta et al.⁴ demonstrated a rigorous approach to identifying and categorizing the regulatory policy influence of one such program: the National Toxicology Program (NTP) Report on Carcinogens (RoC), which for $>40\mathrm{y}$ has conducted cancer hazard identification of environmental and occupational agents (mainly chemicals) to which the U.S. populace is exposed and for which there is some evidence of potential carcinogenicity.⁵ The main findings of Mehta et al. were that hazard identifications carried out by the NTP have influenced regulations and helped to prioritize chemical evaluations. The authors examined in detail the use of NTP RoC evaluations as a starting point for risk assessments carried out by U.S. and state government agencies.⁴ They emphasize a number of key gaps in the available information about the use of the RoC in policy determinations and regulatory actions.

Mehta et al. point out that the 52-y-old program of the Monographs on the Identification of Carcinogenic Hazards to Humans of the International Agency for Research on Cancer (IARC) is frequently mentioned as another authoritative source in many of the U.S. and state regulations they identified. This finding is easily corroborated, for example, by searching the U.S. Federal Register for “IARC Monographs” (with 164 relevant documents found at https://www.federalregister.gov/).

Mehta et al. expect that their approach underestimates the policy influence of cancer hazard identification. This hypothesis is supported by three salient points. First, cancer hazard identification by the IARC Monographs and other programs of hazard identification often has a global impact,^3,6 which would not be captured by the methods they employed. Publicly accessible electronic systems in the United States facilitate access to information on regulatory documents, but such systems are available in only some high-income countries or international bodies, such as the European Union. A search for “IARC Monographs” in the online index of EU law EUR-Lex at https://eur-lex.europa.eu/homepage.html turns up 94 relevant documents. In other jurisdictions, particularly in low- and middle-income countries, a bespoke search process, in consultation with knowledgeable in-country colleagues, may be needed.

Second, Mehta et al. focused their evaluation on promulgated regulations, which are but one type of policy action. Other, nonregulatory actions also may have important impacts on cancer prevention.⁶ These include the issuance of guidance by government agencies that traditionally are nonregulatory [e.g., the National Institute for Occupational Safety and Health (NIOSH)] and by nongovernmental organizations (such as the American Conference of Governmental Industrial Hygienists, the American Cancer Society, the International Labour Organization, and the World Health Organization). For example, the current NIOSH chemical carcinogen policy makes use of hazard identifications conducted by the RoC, IARC, and the U.S. Environmental Protection Agency and recommends “reduction of worker exposure to chemical carcinogens as much as possible through elimination or substitution and engineering controls.”⁷ Also important are persuasive calls to action by various actors (e.g., the European Code Against Cancer commissioned by the European Union and coordinated by IARC, now under the umbrella of the World Code Against Cancer Framework). Although the Code focuses on actions that can be taken by individuals, it notes that to be successful, individual actions must be supported by governmental policies and actions (see footnote at https://cancer-code-europe.iarc.fr/index.php/en/). The newly issued Latin American and the Caribbean Code Against Cancer emphasizes this point firmly.⁸

Third, the emphasis of the analysis and discussion by Mehta et al. was on risk assessment, but highly impactful policy actions can also include banning or restricting the use of an agent found to pose a carcinogenic hazard. Ahead of or after such actions, the research community often provides motivation for banning or restricting carcinogens through demonstrations of anticipated efficacy to reduce either exposures or, more directly, the cancer burden. An excellent example relates to the use of indoor tanning beds by young people. The IARC Working Group on Exposure to Artificial Ultraviolet Light and Skin Cancer concluded in 2005 that convincing evidence showed a causal association between use of ultraviolet (UV)-light tanning beds and melanoma risk, particularly for those exposed at $<35$ years of age.⁹ In 2009, the IARC Monographs program classified use of UV-emitting tanning devices in Group 1 (carcinogenic to humans), noting that they can cause melanoma of the skin and eye.¹⁰ Shortly after these evaluations, some organizations recommended, and many countries instituted, restrictions or bans on the use of UV-emitting tanning devices, particularly among minors. Subsequently, a meta-analysis estimated that the global prevalence of indoor tanning decreased by 70% among adolescents and by 35% among adults in the period 2013–2018, compared with 2007–2012.¹¹ A separate study estimated that 15,102 skin melanomas would be prevented by a U.S.-wide ban of tanning bed use among those 14–17 years of age and would be a cost-effective action after weighing societal costs of the cancer against costs of implementing the ban.¹² The above illustration demonstrates convincingly the value of hazard identification as a means of spurring cancer prevention action for some agents.

In conclusion, measuring policy impacts of cancer hazard identification is important for demonstrating the value of such programs. The approach of Mehta et al. represents a good starting point for identifying and classifying the influence of these programs. Taking a more expansive approach as outlined above may further improve measurement.

Refers to https://doi.org/10.1289/EHP12681