Unemployment is common after breast cancer treatment, according to a recent study.

Researchers from the University of Michigan Comprehensive Cancer Center found that nearly one-third of breast cancer survivors who were working when they began treatment were unemployed four years later. Women who received chemotherapy were most affected.

"Many doctors believe that even though patients may miss work during treatment, they will 'bounce back' in the longer term. The results of this study suggest otherwise," Reshma Jagsi, lead study author, said in a statement. "Loss of employment is a possible long-term negative consequence of chemotherapy that may not have been fully appreciated to date."

For the study, researchers surveyed women in Detroit and Los Angeles who had been diagnosed with early stage breast cancer. They narrowed their sample to the 746 women who reported working at the time they were diagnosed. Participants were surveyed about nine months after diagnosis, and then given a follow-up survey about four years later.

Researchers found that 30 percent of the working women said they were no longer working at the time of the four-year follow-up survey. Women who received chemotherapy were more likely to report that they were not working four years later.

They found that many of these women reported that they want to work: 55 percent of those not working said it was important for them to work and 39 percent said they were actively looking for work.

Usually, many patients take time off of work during chemotherapy treatment to deal with the immediate side effects of the therapy. It is possible this may lead to long-term employment problems, researchers said. In addition, chemotherapy treatments can cause long-term side effects such as neuropathy or cognitive issues, which might also affect job prospects.

Researchers said the findings point to the need to reduce the burden of breast cancer treatment, and reinforce current efforts to develop better strategies for identifying patients less likely to benefit from chemotherapy.

The findings were recently published in the journal Cancer.