Key words
Cancer, clinical trial participation, older patients. (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary.)
Summary
Evidence is mounting that persons over the age of 65 who are reasonably fit tolerate the aggressive chemotherapy treatments often given in cancer clinical trials as well as younger persons do. According to these studies, age alone should not be a barrier to participation in clinical trials of new cancer treatments.
Background
Although most new cases of cancer occur in persons age 65 and over, relatively few elderly patients take part in clinical trials of new cancer treatments. In one large survey of cancer doctors, the reason most frequently given for not referring older patients to clinical trials was the fear that their age made them too frail to withstand the toxicity associated with the more intense treatments.
However, numerous studies have now shown that age alone does not determine a person’s ability to tolerate chemotherapy. Rather, the studies show that older patients whose general health is good benefit from chemotherapy as much as younger patients do. What follows are brief descriptions of just a few of these studies.
The Studies
Lung cancer
In a clinical trial that compared the effectiveness of two chemotherapy regimens involving the drugs carboplatin and paclitaxel, patients age 70 and older with advanced lung cancer lived about as long, with as good a quality of life, as did younger patients in the trial (see the journal abstract by Hensing et al., 2003).
Breast cancer
In an international clinical trial, women ages 66 to 80 who were randomly assigned to receive adjuvant therapy for early breast cancer had significantly better overall survival and disease-free survival than women who received no additional therapy. The benefit of adjuvant therapy was apparent even after a median of 21 years of follow-up (see the journal abstract by Crivellari et al., 2003).
In another report, a review of 6,489 women’s medical records spanning 24 years and four clinical trials found that older women with breast cancer tolerated chemotherapy as well as younger patients did (see the journal abstract by Muss et al., 2005).
Colon cancer
In a combined analysis of the resu lts of seven randomized clinical trials, an international team of researchers found that adjuvant chemotherapy for colon cancer was equally effective and no more toxic in in younger patients compared to patients age 70 and older who were otherwise healthy (see the journal abstract by Sargent et al., 2001).
Multi-study review
In what is thought to be the largest study of this issue so far, researchers reviewed the results of 345 clinical trials conducted by five National Cancer Institute-supported cancer cooperative groups to see how patients aged 65 and over fared compared with younger patients. These studies enrolled patients with many types of cancer, including breast, colon, lung, prostate, and other tumors.
In 15 trials in which more than 40 percent of the enrolled patients were 65 or older, patients who received the experimental treatment lived longer and recurrence of their cancer was delayed for longer, compared with patients who received standard treatment. Older age was not associated with increased harm by the experimental treatments studied in these trials (see the journal abstract by Kumar et al., 2007).
Comment
“[T]here is growing evidence that advanced age alone is a poor predictor of the ability of an individual patient to tolerate and benefit from standard chemotherapy,” writes Thomas A. Hensing, M.D., of the University of North Carolina, lead author of the lung cancer study mentioned above.
In an editorial commenting on another study, Lecia V. Sequist, M.D., and Thomas J. Lynch, M.D., of Harvard Medical School, conclude that “fit elderly” patients with lung cancer can tolerate aggressive therapy as well as younger patients. Regardless of age, they say, patients with good “performance status” – that is, who can perform ordinary tasks and carry out daily activities – are the most likely to have a good outcome from treatment.
The problem of underrepresentation of older patients in cancer clinical trials needs to be addressed urgently, writes Ambuj Kumar, M.D., of the H. Lee Moffitt Cancer Center, University of South Florida, in Tampa, lead author of the multi-study review mentioned above. “[B]y 2030, the population of elderly in the United States will increase two-fold with an accompanying increase in prevalence of cancer in this population.” Studies need to include more elderly participants so doctors know how best to treat this at-risk population.
Research groups have begun to design clinical trials that focus specifically on the elderly. For example, a study jointly sponsored by the National Cancer Institute (NCI) and the National Institute on Aging is comparing the effectiveness of the drug capecitabine with that of standard chemotherapy in women age 65 and over with early-stage breast cancer. This trial is run by the Cancer and Leukemia Group B, an NCI-sponsored Cooperative Clinical Trials Group (see a summary of the protocol).
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