This blog post was written by intern Amanda Garrison, a student at Florida State University. In this series, we aim to help readers understand certain scientific concepts about cancer. The concepts are topics from the Johns Hopkins Kimmel Cancer Center’s annual lecture series Fundamentals of Cancer, Cause to Cure which is directed by oncologist Leisha Emens, M.D., Ph.D. and available to researchers and staff working in the cancer center.
Between 1991 and 2011, an estimate of the number of cancer deaths that were avoided has increased such that nearly 1.5 million Americans are living who might have died from these cancers. But why? Is it because of better treatment? Earlier diagnoses? In a lecture held by John Groopman on "Environmental Causes of Cancer" as a part of the Fundamentals of Cancer lecture series, he asked a group of students to answer this question. Although no student had the complete answer, he says that 15 to 20 years ago, students may have been more likely to answer it correctly, because younger generations of that era were more familiar with the main culprit: the use of tobacco products.
Groopman says that the reason U.S. residents avoided more cancer deaths in recent years is because of the decline of tobacco use. This is a real success, he says, because these statistics provide essential evidence that preventive actions can be taken against cancer. He says that 54.5 percent of all cancer is preventable. Tobacco use and obesity are some examples of factors that, if controlled, can be preventive actions against cancer.
Tobacco consumption was at its peak in 1963, and since then has drastically declined. Today, we have about the same rate of tobacco consumption as we did in 1935, but Groopman says, we still have a long way to go. Fortunately, with the developing successes in early detection and screening these numbers will only get better in the near future.
He says that people in countries with emerging economies often become addicted to tobacco. The country collects a tobacco tax — and then pays the health consequences for decades to follow, he says. He says the most effective means of curbing tobacco addiction is the taxation of tobacco products. If the price is too high, most people will stop smoking cigarettes. But some strategies still used today lure people to the addiction. He says an example of this is chocolate cigarettes for children which are still sold in the U.S. even in 2015.
In fact, Maryland had a large tobacco industry until about 2002. Until recent years, Maryland had the second-highest cancer mortality rate in 1985. Our state ranked number 4 in 1995, but plummeted to number 40 in 2015 due to a number of factors including hospital, city and state-led tobacco cessation, screening and education programs.
With the knowledge that tobacco addition has declined among younger generations in the U.S., this raises the question: what is going to be the next great battle for millennials in terms of environmental causes for cancer?
“Tobacco use may play a small part of the bigger emerging issue here: air pollution,” says Groopman. The most recent data, he says, shows that air pollution causes 7 million deaths per year in the world. This is a major public health challenge for many developing economies who can avoid this developing economic burden through the control of these pollutants.
The World Health Organization classified outdoor air pollution as a carcinogen, which is a substance capable of causing cancer in living tissues. Since the 1940s, scientists have suspected a correlation between air pollution and lung cancer, and Groopman says, there is much more work that needs to be done to understand this connection.