A new analysis published online in the journal Cancer finds treatments can affect memory and more for some time.
Although it has been known that chemotherapy can cause cognitive problems in some patients, the extent was unclear.
This new report confirms that chemotherapy can affect concentration and memory up the three years later.
Also, those who got radiation only often had problems similar to those who had both chemo and radiation.
This suggests chemotherapy isn't solely to blame for these side effects.
The study did not find any evidence of cognitive problems from hormonal therapy such as tamoxifen.