You previously posted you started Tamoxifen in early December. I found this information:
Hormonal therapy. A small number of people receiving hormonal therapy will have noticeable hair thinning. It often begins several months to years after starting treatment with some types of hormonal therapy. But hormonal therapy does not usually cause complete hair loss. The following hormonal therapies are more likely to cause hair loss.
It may be related to the hormone therapy or something else Gayle. Ask your radiation oncologist or the technicians about possible causes for the recent loss of eye brows and lashes.
Keep well and let us know what you discover.
ACH2015 - Andy.