DISEASE CHARACTERISTICS: Eligible patients must have no evidence of disease in addition to 1 of the following features: Stage I, II, or III breast cancer and have received adjuvant chemotherapy and remain clinically free of identifiable disease, but have rising CA15.3 (BR2729) or CEA levels Stage III breast cancer and have completed adjuvant therapy no more than 24 months ago Recurrence in the ipsilateral axilla following a lumpectomy/axillary dissection or modified radical mastectomy Recurrence in the ipsilateral breast following a lumpectomy/axillary dissection Stage II breast cancer with at least 4 positive axillary lymph nodes at 24 months following completion of adjuvant therapy Patients with isolated elevation of the CEA level must have a colonoscopy to rule out colon carcinoma A colonoscopy within the past 5 years is acceptable if there is no strong family history of colon carcinoma, colonic polyps, or inflammatory bowel disease Hormone receptor status: Not specified