Several sources are reporting the results of a new University of Pennsylvania study that indicates, contrary to past opinion, that weight-lifting is actually good for breast cancer survivors:

Study Changes Rules on Breast Cancer Care

“Women treated for breast cancer are warned to avoid heavy lifting – including groceries, babies, and hefty handbags – for fear they’ll develop chronic arm swelling.

A new study led by University of Pennsylvania researchers shatters this guidance. By lifting weights twice a week for a year, breast-cancer survivors with the swelling had fewer debilitating symptoms and flare-ups, even as they grew stronger. . .”
For more: Marie McCullough