Cancer can cause an enormous financial burden for patients — but the burden is worse for patients without paid sick leave.

In a survey of more than 1,300 patients with stage 3 colorectal cancer, researchers found that only 55 percent who were employed at the time of diagnosis retained their jobs after treatment. Patients who had paid sick leave were nearly twice as likely to retain their jobs as those without paid sick leave.

"Financial burden happens in a lot of different ways," says study author Christine Veenstra, M.D., MSHP, clinical lecturer in internal medicine at the University of Michigan Medical School.

"There are costs we can measure, like how much patients pay for prescriptions or doctor visits. Then there are unmeasured costs of cancer care: Did the patient take unpaid time off from work and lose paychecks? Or worse, were they unable to return to work after cancer treatment," she says.

In the study, published in the Journal of the American Medical Association, the researchers found that patients without paid sick leave were more likely to report higher personal financial burden. This includes borrowing money, difficulties making credit card payments, reduced spending for food or clothing, or reduced recreational spending.

After adjusting for factors such as income, education and health insurance, 59 percent of patients with paid sick leave retained their jobs, while only 33 percent of those without paid sick leave did.

"Paid sick leave allows patients to take the time they need for cancer treatment but still keep getting a paycheck," says Veenstra, who is a member of the U-M Institute for Healthcare Policy and Innovation.

She notes that time off is not just about appointment times. Patients may need extended time off after surgery, or they may find they are too sick to work during chemotherapy.

About 40 percent of American workers do not have paid sick leave. It is not mandated under the Affordable Care Act or the Family Medical Leave Act.

"Paid sick leave can really support working Americans who have cancer or other issues as they go through their treatment," Veenstra says. "It may help patients retain their jobs and alleviate the financial strain associated with cancer treatment."