Stage IIIA breast cancer treated alongside a synchronous colon cancer

What happened, in summary

A 58-year-old woman sought care after feeling a lump in the lower outer part of her left breast for three months. She had also lost 6 kg unintentionally over two months. Examination found a hard breast mass and palpable left axillary lymph nodes. During staging and multidisciplinary review, clinicians also identified a separate colon cancer, requiring a coordinated plan for two primary cancers.

The team decided to treat the more advanced breast cancer first. She underwent left modified radical mastectomy without early postoperative complications. Pathology showed a 20 mm grade II invasive ductal carcinoma. Cancer was present in 6 of 22 axillary lymph nodes, and the breast cancer was classified as pT1N2Mx, stage IIIA.

Two weeks later, she underwent surgery for the separate colon primary. After recovering from both operations, adjuvant therapy was directed toward the breast cancer because of its nodal involvement and more advanced stage. She completed doxorubicin, cyclophosphamide, paclitaxel, and trastuzumab, followed by radiation therapy. Endocrine therapy continued afterward.

At two years after surgical treatment, she remained well. CT imaging showed no metastasis or disease recurrence, and she continued clinical and radiological follow-up every six months. Her course required the multidisciplinary team to sequence two operations and select adjuvant treatment for the cancer carrying the greater immediate risk, without mixing the treatment needs of the two primary tumors.