A 65-year-old female patient presented to the emergency clinic with abdominal pain, meteorism, and intermittent rectal bleeding. Colonoscopy was performed, and a hepatic flexure tumor was detected. Histopathological examination of biopsy revealed adenocarcinoma. Thoracoabdominal CT was performed for staging, and a spiculated contour mass was found incidentally on the left breast. Mammography and ultrasonography were performed for the cause of these findings, and suspicious lesions of malignancy were seen in the left breast. Invasive ductal carcinoma was detected in core needle biopsy samples from lesions. In the multidisciplinary council consisting of oncologist, pathologist, radiologist, and general surgery specialist, it was decided to perform breast operation first and then colon operation, followed by adjuvant chemotherapy. In the first operation, left total mastectomy and sentinel lymph node biopsy were performed. One week after her initial operation, the patient underwent right hemicolectomy. After operations, the patient did not develop postoperative complications and was sent to medical oncology department for adjuvant chemotherapy.