The number of lymph nodes removed during breast surgery is one of the top factors in determining if patients develop lymphedema, a new study has found. Researchers conducted phone surveys of 1,338 women between the ages of 65 and 89 years old. They found that those who'd had between five and 15 lymph nodes removed were more than five times more likely to develop lymphedema, while those who had more than 16 nodes removed were ten times more likely to develop the painful swelling disorder.