PURPOSE: The purpose of this study was to assess the impact of aging, comorbidities and symptoms on physical function in patients surviving 20 years since adjuvant treatment for breast cancer. PATIENTS #ENTITYSTARTX00026; METHODS: Patients were originally treated on CALGB 7581 (from 1975-1980), a randomized trial of three adjuvant therapies and reassessed (153 of 193 eligible survivors) 20 years from the onset of therapy for physical function and symptoms by the EORTC QLQ-C30 and comorbidities by the OARS questionnaire. RESULTS: The average age at reassessment was 64.5 years. 66% of patients had at least two comorbidities and 22% had four or more, but relatively little interference with activities. Older patients had greater multimorbidity. Physical function was generally high and comparable to matched population norms. Older patients had greater difficulty with strenuous activities. For every increase in number of comorbidities, physical function score decreased by 5.1 (p<.001). Symptoms were also frequent (80%) and correlated strongly with decreases in function (0-100u scale) (p <.001), to an even greater degree than comorbidities. CONCLUSION: Very long-term cancer survivors have changes in physical function and symptoms largely consistent with their aging suggesting that the impact of cancer and its treatment is attenuated over time and largely replaced by the impact of age-related comorbidities and functional decline.