There is wide variation in the survival of patients whose prognosis is determined using the American Joint Committee on Cancer (AJCC) staging system. A study in 3,728 patients who underwent surgery as first-line treatment has shown that the inclusion of pathologic stage, grade and estrogen receptor status improves the current AJCC staging system; these results were also confirmed in an external validation cohort. These findings indicate that the AJCC staging system should be revised to incorporate these three biologic markers.