Can we eliminate cancer with smoke?

In signing the National Cancer Act of 1971, which embodied his plan for a War on Cancer, President Nixon called for “a national commitment to the conquest of cancer.” In 2016, then-Vice President Biden launched a Cancer Moonshot to accelerate progress against cancer. On February 2 of this year, the White House announced that now President Biden would reactivate the Cancer Moonshot “to reduce the death rate from cancer by at least 50% over the next 25 years and … end cancer as as we know it today.” .” The initiatives of both presidents focused on the research and development of new treatments, but also included cancer prevention and detection and better patient care.

Neither Nixon in 1971 nor Biden in 2016 mentioned reducing cigarette consumption, the leading cause of cancer death in both men and women. However, Moonshot’s February 2 statement acknowledged progress against smoking. (Long the leading cause of male cancer mortality, lung cancer overtook breast cancer as the leading cause of cancer death in women in 1987. Even decades later, two-thirds of women still believed cancer breast was the main cause).

Most recently, on June 21, the Biden administration announced plans for what would likely be the most effective measure to reduce smoking: requiring the reduction of nicotine in burned tobacco products to non-addictive levels. This could also be the single most effective measure to reduce cancer mortality in the future.

If seriously pursued, this controversial regulation will provoke a firestorm of opposition from the tobacco industry, tobacco product retailers, philosophical opponents, and, of course, many smokers. That opposition means implementation won’t happen for years, if ever. (Interestingly, a significant, albeit uncertain, fraction of current smokers support reducing nicotine to non-addictive levels.)

How significantly could very low regulation of nicotine affect cancer mortality? We can get a sense of the answer by looking back, asking how the War on Cancer has progressed to date and how the decades-long battle against smoking has affected that progress.

While progress against cancer affects cancer diagnosis rates, incidence, and 5-year survival, I will focus exclusively on possibly the most important metric: the cancer death rate. Smoking causes a myriad of cancers, including cancers of the mouth, throat, bladder, kidney, liver, stomach, pancreas, colon and rectum, and cervix. However, I will examine only lung cancer, the largest source of cancer mortality from smoking and the most important cancer “marker” of smoking. The other cancer sites have various causes (some unknown), while 80-90% of lung cancers are related to smoking and passive exposure to cigarette smoke.

The prevalence of adult smoking has declined substantially since Nixon declared his war on cancer, from 37% in 1971 to 12.5% ​​in 2020. Both laws and regulations now prevent smoking, as smoking is prohibited in many workplaces and public places, and cigarettes are becoming more expensive due to increases in manufacturers’ wholesale prices and government excise taxes. In addition to reducing the prevalence of smoking, these factors have significantly reduced the percentage of current smokers who smoke every day and the number of cigarettes smokers consume daily. Declines in the percentage of smokers and in the number of cigarettes they smoke have led to a sharp drop in a measure that combines both smoking prevalence and daily cigarette use: the annual adult per capita cigarette consumption (HACCP). Defined as the total number of cigarettes consumed nationwide each year divided by the number of adults age 18 and older, the HACCP has risen dramatically since the early 20th century.the century, when manufactured cigarettes first gained popularity, until 1963, the year before the first Surgeon General’s report on smoking and health. Smoking dropped thereafter, just as dramatically (see figure 1). The marked rise and fall of smoking prompted Harvard historian Allan Brandt to label the 20th century as The century of the cigarette.

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As the development of lung cancer follows the initiation of smoking decades later, lung cancer was essentially unknown at the beginning of the 20th century.the century. Similarly, there is a lag between a decline in smoking prevalence and the subsequent decline in lung cancer. Thus, while the prevalence of smoking in adults began to decline in 1964, lung cancer mortality peaked in 1993, almost 3 decades later.

How has the change in smoking affected the overall death rate from cancer? And how is that rate doing regardless of declines in smoking? Figure 2 below shows a very encouraging picture of the age-adjusted cancer death rate across all sites.

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Cancer mortality overall increased during the 1980s. For both sexes combined, the cancer death rate peaked in 1991. The rate for women also peaked that year. For men, the rate peaked a year earlier. From its peak rates through 2019, the cancer death rate across all sites decreased 32.1% for both sexes combined: 28.2% for women and 38.2% for men. By any measure, this is a huge achievement.

Figure 3 shows the changes in the lung cancer mortality rate during the same period. The rate increased until 1990 for men, the same year cancer mortality at all sites peaked for men. For women, by contrast, the rate of lung cancer increased until 2002. The 12-year gap between the peak rates for the sexes (and the lower peak rate for women) reflects that women started smoking later than men, never reaching the highest smoking prevalence rates of men. , and starting to quit later too. Male smoking prevalence peaked in the 1950s, with more than half of all men smoking, and remained fairly stable until the early 1960s. Female smoking prevalence increased until the Surgeon’s report General of 1964, which interrupted that upward trend. The prevalence of smoking reached a little more than a third for women. The lung cancer death rate for men and women combined peaked in 1993. By 2019, the lung cancer death rate for both sexes had dropped by 43.5%. For women, the rate fell 32.5%. For men, the rate plummeted 55.7%.

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Examine the decline in cancer mortality across all sites except for lung cancer, from 1991, when the all-site rate peaked, the drop was 27% for both sexes combined, or 19.7% for women and 29.8% for the men.

What are the messages to take home? First, with age-adjusted cancer mortality rising everywhere through 1991, President Nixon, who died in 1994, barely lived to see the end of his war on cancer. But it turned a corner, as cancer mortality fell by a third through 2019. Importantly, the rise and fall of cancer mortality moved roughly in tandem with the rise and fall of cancer mortality. lung cancer mortality, especially male lung cancer. The decline in smoking, and thus in lung cancer, has contributed greatly to the impressive decline in overall cancer mortality. Most surprisingly, the decline in male lung cancer death rate accounts for nearly half (47%) of the decline in cancer death rate across all male sites. Of course, not all lung cancer deaths are caused by smoking (up to 20% are not), but offsetting that consideration is the fact that declines in smoking also explain declines in cancers of many other sites.

A second important message: Regardless of progress against smoking, we have made substantial progress against cancer mortality, reflecting other forms of prevention, better detection and early diagnosis, and better treatment.

The third message: President Biden’s ambitious cancer mortality goal is possible. Cutting the cancer death rate in half in the next 25 years will require greater success than the decline in the past 25 years. It will depend on continued improvements in early diagnosis and treatment of cancer. And it may depend on the ability of President Biden’s administration (and likely his successor) to withstand enormous political and legal pressure in trying to implement regulation of very low levels of nicotine. If the stars align, we could shoot at the moon.

Kenneth E. Warner, PhD, is Avedis Donabedian Distinguished University Professor Emeritus and Dean Emeritus of the University of Michigan School of Public Health.

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