36% of cancer patients ages 65 and older participate in clinical trials

A new study finds that only 36% of cancer patients ages 65 and older participate in clinical trials, despite making up 60% of the U.S. cancer population. The study will be published November 15 in the Journal of Clinical Oncology (JCO).

A separate article in the same issue of the JCO summarizes an innovative approach to increasing clinical trial participation among Native Americans in South Dakota.

"If elderly patients do not participate in clinical trials, the treatments resulting from those trials may not be appropriate for them," said Lilia Talarico, MD, of the Division of Oncology Drug Products and Center for Drug Evaluation and Research at the Food and Drug Administration and lead author of the study. "This is a significant concern, given that elderly patients represent the majority of cancer patients in the U.S." Dr. Talarico noted that the FDA recommends that treatments be studied in all age groups for which they will have significant utility, including the elderly, so that the true risks and benefits can be assessed.

Researchers performed a retrospective analysis of 28,766 people participating in 55 clinical trials of new cancer drugs or new indications of already approved cancer drugs from 1995 to 2002. Data on trials for the treatment of leukemia, lymphoma, and cancers of the breast, lung, colon, ovary, pancreas and central nervous system were analyzed according to the following age groups: 65 and older, 70 and older, and 75 and older. The rates of enrollment for elderly patients for each cancer were compared to the corresponding rates in the U.S. cancer population.

Overall, researchers found that patients 65 and older comprised 60% of the U.S. cancer population, but only 36% of the clinical cancer study population. Patients aged 70 and older comprised 46% of the U.S. cancer population, but only 20% of the study population, while patients 75 and older represented 31% of the U.S. cancer population, but only 9% of the study population.

Researchers suggest that elderly patients are less likely to be asked or may be less willing to enroll in clinical trials because of concerns that the treatment will be ineffective or cause debilitating side effects and a reduced quality of life.

Elderly patients were underrepresented in trials for all cancer treatments except those examining breast cancer hormonal therapies. Researchers suggest that this likely reflects the general acceptance among both patients and physicians that hormonal therapy is well tolerated and effective in reducing recurrence and death in women of all ages, including older women.

To increase elderly participation in clinical cancer trials, researchers recommended treatment modifications, study protocols designed for elderly cancer patients, and less stringent eligibility criteria based on cancer and patient characteristics. Elderly patients tend to be excluded from studies with stringent eligibility criteria because of health limitations and concerns about their ability to tolerate chemotherapy, researchers noted.

"Additional concerns for older patients including health care costs, lack of social and home care support, and difficulties with access to care constitute significant barriers. These are not usually considered in the evaluation and treatment of younger patients," said Dr. Talarico.

"Increasing life expectancy has led to a growth in the U.S. elderly population, making it even more critical that elderly cancer patients have better access to clinical cancer trials and treatments," Dr. Talarico added. "With the development of new, selective, and better tolerated treatments, improved access should be possible."