The oldest Americans have higher cancer screening rates but lower cancer survival rates than younger seniors, a new report shows.
Those 85 and older -- a group dubbed the oldest old -- are also less likely to have cancer surgery than their counterparts between 65 and 84 years of age.
Adults aged 85 and up are the fastest-growing age group in the United States, yet relatively little is known about how they're affected by cancer.
"More research on cancer in the oldest Americans is needed to improve outcomes and anticipate the complex health care needs of this rapidly growing population," the study authors wrote in the Aug. 7 issue of the journal CA: A Cancer Journal for Clinicians.
To learn more, researchers analyzed data from nationwide and international cancer registries.
Nationwide, the report projects, the United States will have 140,690 cancer diagnoses this year among its oldest age group and 103,250 cancer deaths. The most common cancers in the oldest old -- lung, breast, prostate and colorectal -- are the same as those in the general population.
Cancer rates among the oldest old peaked around 1990 and have since declined, reflecting decreases in prostate and colorectal cancers, and more recently in breast cancer in women and lung cancer in men, the study showed.
Prostate and lung cancers are the most common causes of cancer death in Americans 85 and older, representing 40% of cancer deaths. Among women, lung cancer is the leading cause of cancer death (19%) followed by breast cancer (13%). Colorectal cancer ranks third for both women (12%) and men (9%).
Adults aged 85 and older are less likely to be diagnosed at an early stage of cancer than those in younger seniors. For example, 57% of breast cancers in the oldest old are diagnosed at an early stage, compared with 68% in 65- to 84-year-olds. For prostate cancer, the rates are 41% and 77%, respectively.
Though the potential harm of screening outweighs the benefit for many people age 85 and older, the age group has surprisingly high screening rates, according to the report.
In 2015, more than one-third of women in that age group reported having a mammogram within the past two years, and 18% reported recent cervical cancer screening tests.
More than half of the oldest men and women had either a stool screening test within the past year or a sigmoidoscopy or colonoscopy within the past five to 10 years. Nearly 30% of the oldest men reported having a PSA test within the past year, the study found.
But the oldest old were less likely have surgery for cancer than those between 65 and 84. For example, 65% of breast cancer patients 85 and older had surgery, compared with 89% of younger seniors.
Carol DeSantis, principal scientistist in the American Cancer Society's Surveillance and Health Services Research Program, led the study.
"The rapid growth and diversification of the population aged 85 years and older will increase demand and complexities for cancer care and could have a substantial impact on medical care resource allocation," the authors said in a cancer society news release.
"There is an urgent need to develop a more comprehensive evidence base to guide treatment decisions for these understudied patients with cancer through increased enrollment in clinical trials and to leverage research designs and infrastructure for generating evidence on older adults with cancer," they added.
HealthinAging.org has more on cancer.