Lori Siegel did not even wait for her hair to grow back. Still feeling the effects of radiation treatments, she sent her résumé to potential employers, bought a new suit and a wig that does not look like a wig, and started going on job interviews.

But so far there have been no offers, and she is convinced that the nine-month gap in her work history gives her away. “It’s like I’m hiding something awful because I got sick,” said Ms. Siegel, 51, who lives on Long Island and is recovering from breast cancer. “I don’t want to bring it up, but I don’t want to lie.”

For Ms. Siegel and many other cancer survivors, money is tight and going back to work a financial necessity. But one of the first big analyses to examine employment rates among American and European cancer survivors has found that they are at significantly higher risk for joblessness than healthy counterparts.

The report, appearing Wednesday in The Journal of the American Medical Association, is an analysis of previously published studies. After accounting for variations in data among those studies, it concluded that cancer survivors in the United States and Europe were 37 percent more likely to be unemployed than healthy peers. In the United States, where it is particularly critical for survivors to hold on to jobs, because they provide health insurance, cancer patients may be at even greater risk of unemployment than patients in Europe, the study suggested.