Orlando, Fla. ? Two out of three children who beat cancer go on to develop other chronic health problems, ranging from heart disease to blindness, because of radiation and other treatments that saved their lives, new research finds.

Cancer treatments have vastly improved in recent years, so today’s patients shouldn’t suffer as many future problems, specialists say.

Nevertheless, the research shows the tremendous medical, financial and emotional burdens that those treated in the 1970s and 1980s are now facing. One study found that 1 in 10 survivors are saddled with $25,000 in cancer-related debt.

“We’ve concentrated so much on our 5- and 10-year survival that we haven’t paid attention to the impact of our treatments,” said Dr. Len Lichtenfeld, deputy medical director of the American Cancer Society.

Indeed, survival is at an all-time high. More than 3 out of 4 children are cured of cancer today, up from 58 percent in 1975.

“But the individuals cured currently pay a large and unacceptable price for that,” said Dr. Harmon Eyre, the cancer society’s medical director.

Nearly 10 million Americans have survived cancer, including 270,000 who were diagnosed when they were 15 or younger.

Researchers around the country studied 10,397 of them who were diagnosed and treated between 1970 and 1986 and 3,034 of their siblings who did not have cancer.

By age 45, cancer survivors were from two to six times more likely than their healthy brothers and sisters to develop various health problems. Examples include heart disease, kidney problems requiring transplants or dialysis, blindness, infertility, mental retardation, paralysis, blood clots, lung problems and even another cancer.

Those who had Hodgkin’s disease fared the worst, followed by those treated for brain tumors, said the lead researcher, Dr. Kevin Oeffinger of the University of Texas Southwestern Medical Center in Dallas.

Radiation is responsible for much of the damage, and doses were much higher decades ago than they are today, he said.

Chemotherapy drugs also have taken a toll. Some, like the widely used breast cancer medication adriamycin, are known to cause heart problems.

Less toxic drugs are needed, and cancer survivors and their doctors need to watch more carefully for health problems and try to prevent them, said Dr. David Johnson, a Vanderbilt-Ingram Cancer Center doctor who is president of the oncology society.

“We want to make primary care physicians aware of these problems as well as patients,” said Johnson, himself a cancer survivor, diagnosed with lymphoma 15 years ago.

The National Cancer Institute funded the study.

A separate one, funded by the Lance Armstrong Foundation, found that half of survivors said their financial and emotional issues were harder to face than the physical issues, and that these needs weren’t met by their doctors.

“We focus predominantly on the medical issues of cancer, yet what this survey says is that the nonmedical issues are as prevalent,” said Dr. Steven Wolff of Meharry Medical College in Nashville.