Researchers say they're zeroing in on factors that may increase the risk of leukaemia after breast cancer treatment.
The findings are a step forward in determining ways to prevent this complication in breast cancer survivors.
While the breast cancer treatments target malignant cells, they can also affect healthy cells and could increase the risk of leukaemia later, the researchers said.
Read: Gene Mutation Seems to Make a Leukaemia More Deadly
The scientists looked at 88 breast cancer survivors with treatment-related leukaemia and found that many had a personal and family history of cancer, suggesting a genetic susceptibility to cancer.
Also, 20 percent of the women had an inherited gene mutation that increases the risk of breast cancer, according to the study published in the journal Cancer.
"The findings justify a long-term, follow-up study of women with and without inherited breast cancer gene mutations who are treated with similar therapy for breast cancer," said study leader Dr Jane Churpek, from the University of Chicago.
Read: Decoding breast cancer
"This would enable us to understand how these genes impact therapy-related leukaemia risk, and whether specific treatments come with higher risks based on a woman's inherited genetics," Churpek said in a journal news release.
Doctors could then have patient-specific conversations about the possible risks and benefits of chemotherapy and radiation treatments for breast cancer, she added.
Read: Leukaemia meds vs ovarian cancer
It can be difficult to determine whether leukaemia in breast cancer survivors is or is not treatment-related, Dr Judith Karp and Dr Antonio Wolff, from Johns Hopkins University School of Medicine in Baltimore, noted in an accompanying journal editorial.
"Existing familial cancer registries that are prospectively following breast cancer patients and their families are uniquely positioned to ascertain the true frequency of subsequent leukaemias and their associations with the therapies received," they wrote.
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