Clinical trials are often short on seniors

More than 60 per cent of cancer patients are older adults — and that will rise to 70 per cent by 2040. Yet seniors are under-represented in clinical trials, making it difficult to assess how treatments are likely to help or harm them.

The newest evidence of the imbalance comes from a Food and Drug Administration analysis. It found that only 40 per cent of patients participating in cancer clinical trials were 65 and older. The analysis was presented last month at the annual meeting of the American Society of Clinical Oncology (ASCO).

Clinical trials investigate the safety and effectiveness of new drugs and therapies, as well as ways to prevent illness and detect conditions early. Their findings help guide medical practice.

Yet, older adults are often not included in research studies to any significant extent. This is especially true for cancer patients in their 70s and 80s, according to the FDA’s data:

• While 19 per cent of breast cancer patients are 75 or older, only 4 per cent of breast cancer clinical trial participants are of this age.

• Although 33 per cent of colon cancer patients are in the 75-andolder group, a mere 8 per cent of patients studied by researchers fell into that age group.

• While 37 per cent of lung cancer patients are 75 or older, only 9 per cent of people of that age are represented in lung cancer clinical trials.

The sobering conclusion: “It’s difficult to practice evidencebased medicine in an older population because the data isn’t there,” said Stuart Lichtman, a professor of medicine at Weill Cornell Medical College in New York and president of the International Society of Geriatric Oncology.

And it’s not just cancer. Across medical conditions that disproportionately affect seniors, people 65 and older have a poor showing in clinical trials.

“There’s often an assumption that drugs only need to be tested in younger people and results can be extrapolated,” said Consuelo Wilkins, an associate professor of medicine at Vanderbilt University Medical Center who, with colleagues, is overseeing a major grant to help bring more seniors, blacks, Hispanics and other groups into clinical trials. “But we know that how older adults respond to medications and interventions and their risk for adverse events is different based on their physiology.”

Researchers often find older adults unsuitable for trials for multiple reasons: Seniors may have multiple illnesses — diabetes and hypertension in addition to cancer or Alzheimer’s disease — that could complicate the study’s results, or they may already be taking medications that could interact with therapies being examined.

Also, older adults may live alone and not have someone who can accompany them to the study site for tests and procedures — a significant concern for Alzheimer’s trials, which typically require a caregiver to provide input about the patient’s condition and progress. Also, some seniors can’t get around easily. And some are frail.

Responsibility falls to a large extent on physicians, said Richard Schilsky, chief medical officer for ASCO, noting that “they don’t ask older adults whether they want to participate or not. It’s a combination of concern that older patients might be unable to comply with a trial’s requirements, which are usually quite rigorous, and concern that specified therapies might be too toxic.”