Graphic by Jim Woolace / Fred Hutch News Service
Here’s a milestone worth celebrating: The U.S. cancer death rate has dropped 27 percent over the past 25 years.
The encouraging stats come from the American Cancer Society’s latest annual report. The steady decline in smoking rates and better screenings and treatment helped drive the drop in cancer deaths.
But troublesome trends lurk in the data. Obesity-related cancers are increasing, as is a gap between rich and poor Americans. Deaths in certain kinds of cancers — notably prostate — are no longer dropping.
The report offers a moment to reflect on the benefits of public health and research efforts over the years — and look ahead to what’s next. We asked a few experts at Fred Hutchinson Cancer Research Center to dive deeper into the data and explain how we can accelerate progress against cancer for everyone.
The report highlighted progress in the historic racial gap in cancer death rates. But now an economic gap is growing, particularly in preventable cancers tied to smoking and obesity.
“Cancer mortality is improving for both the poor and the affluent, but it’s improved much more for the affluent,” said Dr. Joseph Unger, a Fred Hutch health services researcher and biostatistician. “This is inevitably about access to care and the skyrocketing costs of cancer care.”
Unger said there are two ways to close that gap: bring good care to the patients, or bring the patients to good care.
“This report suggests that efforts at both the community and individual level can be helpful,” he said. “It’s important to provide the infrastructure to enable the delivery of quality cancer care to patients living in less affluent communities. Technology can also be our friend by creating strategies to link local providers to large oncology centers."
At the individual level, we need to make sure patients have the right insurance resources as well, he added. But it’s likely an issue that goes beyond simply having insurance.
“Patients with limited financial means will be more sensitive to both the direct costs of care — such as co-pays and co-insurance costs — and the indirect costs of care, such as time off work or travel costs.”
And it’s not just rich vs. poor communities, he added. Cancer patients in rural areas of the U.S. die of their disease at significantly higher rates than those residing in U.S. cities. In a recent paper, Unger and other Fred Hutch scientists observed that when treated in clinical trials — in which patients receive good access to care by design — the gap in survival disparities between rural and urban patients disappeared.
Unger and his colleagues are currently examining whether disparities in outcomes between poor and affluent patients also exist in patients receiving care in clinical trials. Their findings could shed light on this aspect of the ACS report.
“If the disparity in outcomes between poor and affluent patients disappears in clinical trial patients, the implication is clear,” he said. “Access to quality cancer care can help resolve disparities.”
Spotlight on prostate cancer trends
The ACS report seemed to offer mixed news about the second-leading cause of death in men.
The good: Prostate cancer mortality rates plummeted by half over the past two decades.
But the decline flattened out from 2013-2016, and the reason for that leveling-out is the subject of ongoing debate in the field. Some experts wonder if that’s related to a 2011 decision by the U.S. Preventive Services Task Force to stop recommending routine screening of men using the PSA blood test.
And despite strides against the disease, we haven’t solved the problem of aggressive prostate cancer. But work underway at Fred Hutch and elsewhere could help by pinpointing the men who are more likely to develop those cancers. “Being able to predict aggressive cancers before they start is going to be our best bet,” said Fred Hutch biostatistician Dr. Ruth Etzioni.
A new lead is the BRCA2 gene, which appears to be associated with a higher risk of lethal prostate cancer. The BRCA genes are famously associated with breast cancer risk, but BRCA2's link with prostate cancer has come under scrutiny. It turns out that not only are mutations in BRCA2 (and in other genes involved in repairing DNA) associated with the risk of aggressive prostate cancer, Etzioni said, but patients with these mutations in their tumors appear to respond differently to certain types of chemotherapy.
Dr. Peter Nelson, a Fred Hutch prostate cancer researcher and oncologist, agreed that a key objective for physicians will be smarter screening — focusing on those at-risk individuals who would benefit the most, while avoiding needless screening of those who won’t benefit.
Meanwhile, the promise of precision medicine and its patient-tailored treatments should improve outcomes, he added.
“Advanced prostate cancer is actually composed of many subtypes, and some of those types respond better to certain kinds of treatment,” Nelson said. “In the future, we won’t treat them all the same but according to the different vulnerabilities written into their genomes. This precision-medicine approach will continue to extend and improve quality of life.”
Snuffing out smoking rates
The report hammers home the clear relationship between smoking cessation and reduced risk of lung cancer, long the nation’s leading cancer killer, says Fred Hutch smoking-cessation researcher Dr. Jonathan Bricker.
“Ten years after quitting, your risk of lung cancer is cut in half,” he said. “So the decline in U.S. smoking rates are continuing to have an enormous payoff in terms of declining cases and deaths from cancer. As cohorts of people who quit or never smoked continue to age, we will see even greater payoffs in the future.”
But there are still 35 million adult smokers in the U.S., Bricker added.
“So the fight to control tobacco use must continue if we want to see future progress in declining lung cancer cases and deaths,” he said. “This means continued funding of research into interventions for tobacco cessation with broad public research and effectiveness."
Obesity on the rise
Smoking may be on the wane, but obesity is on the rise.
Obesity increases risk for several of the cancers that have increased in incidence — especially malignancies of the breast, endometrium, liver and pancreas, said Dr. Anne McTiernan, a Hutch cancer prevention expert. “This is especially concerning since the obesity rate continues to be high in this country and around the world.”
As long as the obesity trend continues, she said, we can expect the risk of obesity-related cancers to increase.
“At Fred Hutch, we are testing how weight loss can affect biology so we can understand if weight loss can reduce the risk of getting cancer,” McTiernan said.