It is most frequently seen after lymph node dissection, surgery and/or radiation therapy, in which damage to the lymphatic system is caused during the treatment of cancer, most notably breast cancer. In many patients with cancer, this condition does not develop until months or even years after therapy has concluded. Lymphedema may also be associated with accidents or certain diseases or problems that may inhibit the lymphatic system from functioning properly. In tropical areas of the world, a common cause of secondary lymphedema is filariasis, a parasitic infection. It can also be caused by damage to the lymphatic system from infections such as cellulitis.