Nonetheless, due to Halsted and Meyer's work, it was possible to cure some cases of breast cancer and knowledge of the disease began to increase. Standardized treatments were created, and controlled long-term studies were conducted. Soon, it became apparent that some women with advanced stages of the disease did not benefit from surgery. In 1943, Haagensen and Stout reviewed over 500 patients who had radical mastectomy for breast cancer and identified a group of patients who could not be cured by radical mastectomy thus developing the concepts of operability and inoperability. The signs of inoperability included ulceration of the skin, fixation to the chest wall, satellite nodules, edema of the skin (peau d'orange), supraclavicular lymph node enlargement, axillary lymph nodes greater than 2.5 cm, or matted, fixed lymph nodes. This contribution of Haagensen and his colleagues would eventually lead to the development of a clinical staging system for breast cancer, the Columbia Clinical Classification, which is a landmark in the study of biology and treatment of breast cancer.