Hyman Muss, MD
Although patients with cancer have high rates of comorbidities that often correlate with poorer outcomes and complicate treatment decisions, hard data are frequently lacking on the interaction between specific regimens and health conditions.
Oncology experts are increasingly turning their attention to the disconnect between patient populations recruited for the clinical trials that lead to the approval of new drugs and individuals in the real world who are treated with those medicines. A push for better metrics to assess and manage comorbidities is also under way.
The absence of patients with comorbidities from clinical trials is generally attributed to trial sponsors’ concerns about jeopardizing the approval of agents that would prove efficacious in healthier patients as well as about the safety of trial participants.
However, new research findings show that the processes that steer these patients away from drug studies go beyond specific eligibility criteria to a broader cultural failure to integrate people with comorbidities—who represent a majority of patients with cancer—into trials.
Patients with comorbidities were less likely than those without a comorbidity to discuss clinical trials with their doctors or be offered a spot in a trial, with the impact more pronounced as the number of secondary conditions rose, according to self-reported patient data presented at last month’s American Society of Clinical Oncology (ASCO) conference.1
Hypertension, prior cancer, and hearing loss had the greatest impact, even though good hearing is rarely, if ever, a listed eligibility requirement. Patients with at least 1 of those 3 comorbidities were 11% less likely to discuss clinical trials, 18% less likely to be recruited, and 22% less likely to participate.
The study’s findings illustrate the challenges that are faced in efforts to improve access to new drugs for older people and those with comorbidities and to produce more trial data to guide treatment decisions in those populations. ASCO and Friends of Cancer Research have proposed a set of broader eligibility criteria that would boost the number of patients with comorbidities in trials, but “this effort alone is unlikely to substantially increase trial participation rates overall,” the study concluded. Advocates argue that the culture around trial enrollment is beginning to change, but they say it could take years to make a significant impact.
“Clinical trial populations are always healthier and richer than the people in the community,” said Hyman B. Muss, MD, a specialist in geriatric oncology at the Lineberger Comprehensive Cancer Center at the University of North Carolina at Chapel Hill and a Giants of Cancer Care®
“A lot of the data we get on the Olympic athletes who are going on trials [are] really not applicable to someone who is 75, with bad arthritis, who’s using a cane,” he said in an interview with OncologyLive®
. “And yet we treat them the same way, and then they frequently will have horrendous toxicity because those patients are not included in the trials. We’ve been trying to fix it, but it’s been woefully slow.”
Impact of Comorbidities
Studies have found a wide range of comorbidity rates.2
A large study of patients aged 66 years and older with cancer found that 40% had at least 1 of 15 major comorbid conditions, compared with 32% of people without cancer (Figure
Twenty-five percent of the patients with cancer had 1 condition, and 15% had 2 or more. Diabetes was most common at 16.0%, followed by chronic obstructive pulmonary disease (COPD) at 15.5%, congestive heart failure at 9.7%, and cerebrovascular disease at 6.0%. Comorbidity rates were about 53% in patients with lung cancer, 41% with colorectal cancer, 32% with breast cancer, and 31% with prostate cancer.
Figure. A Snapshot of Comorbidities in Individuals ≥66 Years3
Other studies have found greater prevalence of comorbidities. In the study presented at ASCO, 66% of patients with cancer said they had at least 1 comorbidity, led by hypertension at 35%.1
Another study found that 92% of patients had a comorbidity, with an average of 2.7 conditions per person.4
In people both with and without cancer, multiple chronic conditions are more common in older patients, racial minority groups, and patients who are in poverty.5,6