As cancer incidence rates continue to rise, researchers look for answers.
With advances in genetic research, screening procedures, and education, the battle against cancers of all types has seen considerable progress. Cancer mortality rates dropped one-third in the US alone between 1991 and 2021, according to the American Cancer Society. Advances in health care averted more than 4 million deaths.
However, this progress is jeopardized by a looming threat: the incidence rates for six of the top 10 cancers have continued to rise, with the World Health Organization now predicting global rates could skyrocket by more than 75 percent by 2050.
Wafik El-Deiry, MD, PhD, director of the Legorreta Cancer Center, notes that, for a nation like the US, the growth of an already large population has inevitably led to the increase of cancer rates and absolute cancer numbers. The ACS predicts there will be 2 million more new cancer cases in 2024, primarily breast, prostate, pancreatic, melanoma, kidney, and endometrial, he says. Pinpointing the drivers of these increasing rates is uniquely challenging.
The urgency is exacerbated by incidence rates that have risen considerably among adults under 50. In a study by the NIH, early-onset cancer rates increased across the board from 2010 to 2019 in the US, and gastrointestinal cancers had the fastest-growing rates among them.
“It’s a difficult problem because cancer is a disease of both environment and genetics,” says El-Deiry, a practicing oncologist, Associate Dean for Oncologic Sciences, Mencoff Family University Professor of Medical Science, professor of pathology and laboratory medicine and an American Cancer Society Research Professor. “Some people are predisposed to cancer, as they may inherit a mutated gene that ultimately predisposes them to specific and sometimes multiple types of cancer.”
While breakthroughs in genetics have yielded improved treatment options, it isn’t as simple as turning researchers’ attention to underlying genes. For instance, scientists understand the genes that can cause hereditary colon cancer. However, they don’t know exactly how additional, outside factors impact these genes and lead to early-onset development. Singling out these genes among a broad patient population isn’t as simple as picking them out from a line-up—researchers need to understand the precise mutations among specific genes and take into account contributing factors like the environment and the presence of other diseases that can cause other types of cancer.
“That doesn’t mean it’s not being driven by genetics, but we will need more resources because finding genetic causes may not be so straightforward,” El-Deiry says. “We have some idea of what to look for and how to look for it.”
El-Deiry also points to environmental factors like second-hand smoke, air quality, and soil pollutants as potential contributors to cancer rates. Exposure to these pollutants, on top of various chemicals and radiation, create a broad swath of risk factors that makes it hard to establish a clear causality between any one known environmental factor and rising incidence rates.
An Unfortunate Distinction
When compared nationally, Rhode Island occupies some alarming spots in cancer rankings, like the highest bladder cancer rate per capita in the country. Areas like the Jewelry District in Providence face unique issues tied to their industrial past, as dyes, chemicals, and metals found their ways into the soil, says El-Deiry. Industrial pollution could exacerbate this higher rate, but research is still needed to establish a clear correlation.
El-Deiry says scientists are also trying to account for links between cancer rates and microorganisms within the human body. We host billions of microorganisms within our microbiomes, which can vary greatly due to factors like diet and antibiotic use. Because of the microbiome’s link to the immune system, such organisms could stimulate the creation of certain substances that can promote cancer from within the body itself. Researchers are also weighing the influence of microplastics or nanoplastics, which recent studies have shown can disrupt everything from the immune system to fetal development.
“I think among younger people in the US, there is a culture that uses a lot of antibiotics, and that has come up in research as well,” El-Deiry says. “We’ve altered our gut microbiomes and perhaps interplay between the bugs and the immune system, obesity and inflammation contribute to certain early onset cancer rates, but I think that’s a work in progress.”
Person-Centered Care
Researchers must also address racial disparities in cancer cases. The ACS reports that mortality rates are “two-fold higher for prostate, stomach, and uterine corpus cancers in Black people and for liver, stomach, and kidney cancers in Native American people.” Don Dizon, MD, the head of community outreach and engagement at the Legorreta Cancer Center, says that health care needs to move away from strictly race-based assessments for cancer risks and screening.
“I think we need to move toward an ancestral understanding of the risks for cancer, especially as we, as a society, become multiracial and multiethnic,” says Dizon, a professor of medicine and of surgery. “We need to understand what role ancestry plays in cancer risks with better methods of screening.”
Public health officials, researchers, and clinicians alike must utilize coordinated efforts to include underrepresented populations in clinical trials, Dizon says. There needs to be greater diversity in person-centered care, both in terms of clinical approaches and patient representation, in combating these rising incidence rates.
“We need to understand that we’re still learning that no one person has the answers, and we should never settle for what we know now,” he says.
In Rhode Island, the public health-oriented approach to care is reflected in Brown’s aim to create a statewide cancer center, El-Deiry says. Brown established the Legorreta Cancer Center in 2020; it has more than tripled funding from the National Cancer Institute over the last four years. This will help researchers leverage emerging technologies that can perform highly technical tasks like pulling tumor cells from blood samples, creating advanced visualization and modeling tools, and creating artificial intelligence systems that can recognize patterns while contributing to both clinical trials and outcomes.
“This will help us provide more personalized care, new screening, prevention and treatment approaches to people in our state,” he says.
Reducing cancer incidence rates will ultimately require a multi-pronged approach to gain a better understanding of the diseases.
“We’re not necessarily talking about curing cancer at this point. Nothing would make me happier, certainly, but the best way to deal with the cancer burden is to prevent it and remove it when it is 100 percent curable,” El-Deiry says. “Realistically, I think we can do a lot just by adopting preventative measures, avoiding behaviors that increase exposure risks, and promote vaccinations against certain virally caused cancers. There are opportunities to develop clinical trials and vaccines to keep cancer at bay, and those processes are very powerful if we can take advantage of them.”
