Chicago ? Although cancer is usually a disease of the elderly, a large government review finds older people are often excluded from studies intended to discover better drugs to treat their disease.

Older people may be left out for legitimate reasons, such as having other serious illnesses along with their cancer. But experts contend that many more should be offered a chance to take part in these experiments, known as clinical trials.

The elderly could benefit from the experimental treatments, just as younger patients do, and their enrollment is essential for doctors to learn whether the drugs are safe and effective in people their age.

Furthermore, many top specialists say doctors should be more willing to offer state-of-the-art treatments to the elderly patients in day-to-day care. Instead, the most aggressive therapy often is reserved for younger patients.

“It’s not just clinical trials. They are also less likely to get standard treatments,” even such obvious therapies as radiation to ease pain, said Dr. Lilliam Siu of Princess Margaret Hospital in Toronto.

The underrepresentation of older people in drug studies was documented by the Food and Drug Administration, which reviewed data from 29,350 patients enrolled in studies of new cancer drugs, or new uses for older ones, since 1995.

While earlier studies have reached similar conclusions, Dr. Lilia Talarico said hers is the first to look at age differences in studies involving various kinds of medicine. For instance, she found that older women with breast cancer are just as likely as younger patients to enter studies of hormonal treatments, which typically have mild side effects. But they are much less likely to get into chemotherapy studies.

Overall, she found that while about 60 percent of all newly diagnosed cancer is in people older than 65, they make up 36 percent of patients in drug studies.

“Our knowledge about drugs comes from clinical trials,” she said. “If a drug is only tried in a certain population, we can’t extrapolate that to everybody.”

While it may be unrealistic to expect studies to enroll older people in numbers reflecting their full cancer burden, “we want to make sure clinical trials contain an adequate number so we can answer whether the effect of treatment is the same as in younger patients,” Talarico said.

She presented her data earlier this month at the annual scientific meeting in Chicago of the American Society of Clinical Oncology.

Dr. Giuseppe Curigliano of the European Institute of Oncology in Milan, Italy, surveyed the treatment of 2,999 women with breast cancer that had spread to their lymph nodes. He found that 85 percent of those younger than 65 got standard radiation treatment after lumpectomies, compared with just over half of older women.

Nevertheless, several studies have found that older cancer patients benefit just as much from treatment as do younger people.

Dr. Hyman Muss of the University of Vermont reviewed four large studies of breast cancer treatments involving 6,489 patients.

Although just 8 percent of the volunteers were older than 65, the studies taken together show that chemotherapy improved their survival equally as well as it did the younger women’s.

“The job of the physician is to give the best treatment to their patients, period,” Muss said. “Using age to minimize treatment is a bias. Age as a bias is wrong.”