Overall the picture in cancer in the U.S. is looking rosy: the sharpest one-year decline in death due to cancer, from 2016-2017, continues a 26-year-long trend in declining cancer mortality rates, according to the latest data published Wednesday by the American Cancer Society. This drop reflects a decline in death from the top four cancers: lung, breast, colorectal and prostate — but primarily lung. More people die of lung cancer than of the other top cancers combined.
The decline in overall cancer mortality is a well-established trend that began in 1991, said Fred Hutch experts, and reflects the successful implementation of a broad range of research advances including in prevention, early detection and treatment, such as new immunotherapies. Thanks to this progress, about 29 million deaths from cancer have been avoided.
The new ACS data show that since 1990, lung cancer death rates dropped 51% in men. Since 2002, they dropped 26% in women. This lag reflects gender-based differences in smoking trends; while women started taking up smoking later than men, they have also been slower to give it up, according to the ACS.
Breast cancer mortality among women dropped 40% since 1989 and prostate cancer mortality fell 52% since 1993. Death due to colorectal cancer declined 57% in women since 1969 and 53% in men since 1980.
Motivation to continue improving
Every death avoided is cause for celebration, but it’s not yet time to throw a Cancer Conquered party — not even for lung cancer, where advances in detection and treatment, and behavioral changes, have contributed most to the declining death rate.
“We’ve made great progress to reduce mortality in lung cancer, but the startling thing is that the five-year survival rate is still only 19%,” said Dr. Christopher Li, a Hutch epidemiologist who studies breast cancer risk factors. “For the majority of patients, this is still a highly lethal disease. It’s a motivation to continue improving treatment strategies even though we’ve made progress.”
The overall positive trends mask a lack of progress in other types of cancer, including endometrial and pancreatic tumors.
“These cancers are difficult to treat. There has not been a ground-breaking change in the way we treat them, as we’ve seen for other types of cancer, which more strongly reflect innovations in new treatment strategies in their mortality rates,” Li said.
The data also reflect systemic challenges that have yet to be overcome, he said.
“For almost all cancers, African Americans have poorer survival rates than whites, regardless of stage of cancer,” Li noted. “These trends have been present for decades, probably longer, and we have not been able to bridge that.”
Cancer in young people
This year’s report devoted a special section to cancer in adolescents and adults through age 39. Or, in cancer-stat parlance, AYAs (for adolescents and young adults). Melanoma is one of the most common cancers in young adults, while cervical cancer is the second-leading cause of death from cancer among women aged 20-39.
Both of these cancers are potentially preventable, said Dr. K. Scott Baker, a Fred Hutch epidemiologist who studies the long-term effects of bone marrow transplant in young people.
Take cervical cancer. Nearly all cases are caused by infection with the human papillomavirus, or HPV. This means that “cervical cancer is highly preventable through HPV vaccinations,” Baker said.
Indeed, Australia, which introduced no-cost HPV vaccinations in 2007, is beginning to see a dramatic decline in infection with cervical cancer-linked HPV strains, and has one of the lowest incidence rates of cervical cancer in the world.
Risk of melanoma, too, can be reduced through sun-safe behaviors, like using enough sunscreen and avoiding tanning beds.
The ACS report noted that colorectal cancer is on the rise among people younger than 39.
“Part of the concern there is that this is an age group not getting colon cancer screenings,” which generally start at 45, Baker said. It’s not clear whether increasing rates in colon cancer in young adults will lead to a change in screening guidelines, he said, but it does suggest that young adults and their care providers shouldn’t dismiss potential symptoms out of hand. “It’s certainly not what a 20-year-old would thinking about,” Baker said.
That’s one reason that cancers in young people are often diagnosed at a later stage. Younger adults are also less likely to have insurance and more likely to delay going to the doctor until they are really sick, Baker said.
Getting cancer at a young age can also set someone up for a higher risk of health issues, including heart attacks, down the road, but some of these may also be preventable, Baker said. Baker and colleagues are studying interventions, including exercise programs and health education, that can help young cancer patients decrease the chance that they’ll have to deal with long-term health effects of cancer treatment.